HK40008560A

HK40008560A - Addressing a trusted execution environment using encryption key

Info

Publication number: HK40008560A
Application number: HK19132410.2A
Authority: HK
Inventors: M·F·诺瓦克
Original assignee: 微软技术许可有限责任公司
Priority date: 2017-01-26
Filing date: 2017-12-20
Publication date: 2020-06-12

Description

Addressing trusted execution environments using encryption keys

Technical Field

The present disclosure relates generally to trusted and/or isolated execution environments in computing devices, and more particularly to securely delivering one or more secrets or keys to a trusted execution environment.

Background

A Key Management System (KMS) is a secret store. The secret typically has a public ID, a protected value, and a policy to control who can obtain the value. In some cases, the secret may also have an expiration date and other metadata, etc. In a typical use case, the requestor authenticates to the KMS, establishes a secure channel, requests a secret value by providing a secret ID, and expects the KMS to return a plaintext secret value thereto. This value is protected from unauthorized eavesdropping and tampering by a secure channel between the requester and the KMS.

A trusted execution environment (TrEE) as used herein may include any one of the following: a Virtual Secure Mode (VSM) trusted application (trustlet), an SGX application, an ARM TrustZone application, or some other similar vehicle (vehicle). TrEE typically has some unique attributes. TrEE typically has a complete encryption stack (in other words, various encryption primitives in the entire spectrum can be assumed, from secure random number generation to a complete menu of hash, encryption and signature libraries using keys). The TrEE also typically has or is associated with a few or limited I/O facilities, often limited to request driven architectures where requests originate from the untrusted "outside world". For example, a VSM trusted application may use an unauthenticated Remote Procedure Call (RPC). The TrEE may also have access to keying material or data that is not available externally to the TrEE. This allows the TrEE to use untrusted I/O to store data, which is then read back, ensuring tamper resistance and state confidentiality. TrEE typically also has or is associated with: provable code, configuration, and keying material. In particular, provable key material allows the TrEE to receive messages encrypted to it from third parties and to sign messages from the TrEE to the third parties.

As with other applications, there may be security restrictions using KMS with TrEE. Thus, security can be improved with keys from the KMS together with or in the TrEE.

Disclosure of Invention

Illustrative examples of the present disclosure include, but are not limited to, methods, systems, and various devices. In one aspect, a method for transferring protected data to a nested trusted execution environment (TrEE) associated with a potentially untrusted requestor, including a trusted application running on top of a secure kernel, may be performed at least in part by a target protocol header or other intermediary between the requestor and a key management system or other memory of the protected data. The target protocol header may receive a request for protected data from a potentially untrusted requestor and an attestation statement of the security kernel. The target protocol header may encrypt the transport encryption key with a second encryption key derived from the attestation statement. The target protocol header may retrieve the protected data and encrypt the protected data with a transport encryption key and an authentication tag that binds the requestor with the trusted application ID. The target protocol header may provide the encrypted transport encryption key, the encrypted protected data, and the encrypted authentication ticket to the requestor.

Additional features of the systems and methods are described below. The features, functions, and advantages can be achieved independently in various examples or may be combined in yet other examples, further details of which can be seen with reference to the following description and drawings.

Drawings

Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which:

1A, 1B, and 1C depict three examples of systems and processes for exchanging keys between a requestor and a key management system.

FIG. 2 depicts an exemplary diagram of a control program monitor implementing an isolated area or trusted execution environment (TrEE).

Fig. 3 depicts an example process for transferring protected data to a trusted TrEE using an intermediate target protocol header.

Fig. 4A and 4B depict another example process for transferring protected data to the TrEE using an intermediate target protocol header.

Fig. 5A and 5B depict an example process for transferring protected data to a nested TrEE using an intermediate target protocol header.

FIG. 6 illustrates an example system in which one or more of the described processes can be implemented.

Fig. 7 depicts an example of a data structure for securely transferring keys and/or protected data to the TrEE.

Fig. 8 depicts another example process for transferring protected data to nested tees using an intermediate target protocol header based on an external TrEE's encryption key.

Fig. 9 depicts another example process for transferring protected data to nested tees using an intermediate target protocol header based on an internal TrEE's encryption key.

FIG. 10 depicts an example general-purpose computing environment in which the techniques described herein may be implemented.

Detailed Description

Systems and techniques are described herein for securely transferring at least one key (e.g., a signing key or encryption key) or protected data/secret to a trusted execution environment (TrEE) of a computing device, such as one or more physical or virtual computing devices. In one aspect, an intermediary (intermediary) may be implemented between a key requestor and a key management system or an entity that owns the protected data. The intermediary may be referred to herein as a target protocol header. The key requestor may be associated with a secure execution environment or TrEE, which may include one or more of a VSM trusted application, an SGX application, an ARMTrustZone application, or some other similar vehicle. The TrEE may be isolated from the requestor. The requestor may request one or more secrets to be delivered from the target protocol header to the TrEE or to a particular trusted application executing within the TrEE. In response to the request, the target protocol header may communicate with a key management system or other entity holding the secret to obtain one or more secrets for transmission to the TrEE. The target protocol header may be specific to the protected data at the (target) TrEE so that a requestor or attacker cannot access the protected data.

In some aspects, implementation of the target protocol header may negate the need for a secure channel between the requestor and the key management system. The target protocol header using the TrEE target technology described herein may also enable one or more secrets or data to be sent to the TrEE or a nested TrEE (e.g., a trusted application running on top of a secure kernel) such that the secret/data is not accessible to the requestor. In some cases, the requestor may be untrusted or potentially untrusted, such that the owner of the protected data may wish to keep the protected data from being accessed by the requestor for various reasons. In some cases, it may be difficult or cumbersome to prove that the requestor is trustworthy or to ensure that the requestor remains trustworthy. Many of these concerns can be negated, assuming that the requestor is not trusted and the TrEE is isolated from the requestor. As will be described in greater detail below, such isolation may greatly improve security against different types of attacks, and may provide other benefits and advantages.

FIG. 1A illustrates an example system and process 100a for exchanging keys between a requestor and a key management system. As shown, a requestor or requesting device 120 associated with a client device or client side 110 may communicate with a key management system associated with a server or server side 105 or some holder of a desired secret 115. The requestor 120 may request one or more secrets or protected data from the key management system 115, e.g., to access certain protected data, perform one or more protected processes, etc. The supplicant 120 and the Key Management System (KMS)115 may utilize a public-private key security system or other key protocols known in the art to exchange desired secrets/data.

At operation 125, the supplicant 120 may first authenticate with the KMS115 and establish a secure communication channel via any technique known in the art. Operation 125 may include utilizing a public key system or the like. Subsequently, at operation 130, the requestor 120 may send a request to the KMS115 for one or more secret/protected data utilizing the secure channel established via operation 125. After authenticating the request, KMS115 may transmit the secret or the requested data back to requester 120 over a secure communication channel at operation 135. As is standard in the art, the secret/requested data may be transmitted over the secure channel at 135 without requiring any additional protection over the secure channel. As a result, the secrets/data transmitted at operation 135 may be exposed to the requesting device 120.

Fig. 1B illustrates an example system and process 100B for exchanging one or more secrets or protected data between a requestor 120 and a KSM 115 on behalf of a trusted execution environment (TrEE)140, an enclave (enclave), or other item for indicating an isolated execution environment associated with the requestor 120. TrEE140 may be isolated from requestor 120 such that code and/or data contained in TrEE140 may not be accessible (e.g., readable and/or writable) by requestor 120. Fig. 2 illustrates an example 200 of a trusted execution environment, wherein a computing device 205 may include logic 210 (e.g., code) and state information 220, such as data. The state information 220 may be stored or located in the isolation region 215, such as may be without risk of unauthorized access. In some cases, the data 220 within the isolated region 215 cannot be read or written directly by any entity other than the logic 210 associated with the isolated region 215. The isolation logic 210 decides what type of access it will allow to what type or portion of data 220. In one example, logic 210 may allow incrementing and reading of values associated with data 220, but may not otherwise modify data 220. In another example, logic 210 may allow cryptographic operations using the key without authorizing access to the value of the key itself. In the illustrated example, logic or code 210 may be in a general or accessible area of CPM 205; however, it should be understood that in some cases, logic 210 may also be located within the same or different isolation regions as state information 220.

Returning to system 100b, a Target Protocol Header (TPH)150 may be implemented on server side 105 to serve as an intermediary between requester 120/TrEE 140 and KMS 115. A protocol header may refer to a software implementation of a protocol handler, typically oriented to a system that does not itself use a particular protocol. Targeting may refer to cryptographic targeting of the execution environment. In general, the term may refer to software and/or hardware that implements a protocol for retrieving secrets that targets a response at the TrEE. In some aspects, the target protocol header 150 may be implemented as a virtual or cloud resource, e.g., which may run on different hardware, software, and/or separate from the KMS 115. In some aspects, an entity such as a data center may host and/or provide target protocol header 150 as a service. The target protocol header 150 may perform two main functions: 1) communicate with KMS 115/obtain secret or protected data from external entities, and 2) target responses to TrEE140 of requester 120. As a result of the use of the target protocol header 150, the supplicant 120 need not authenticate directly to the KMS 115. The KMS115 generates its secret to the target protocol header 150 rather than to the requestor 120. The function of target protocol header 150 is to target the response of TrEE140 of requester 120 to ensure that requester 120 cannot obtain the plaintext of secret/protected data. Instead, the target protocol header 150 may instead authenticate to the KMS115 on behalf of the requester 120 itself, but may do so with or without the identity of the requester 120. In some cases, target protocol header 150 may need to be confident that the secret it will return to TrEE140 of requestor 120 will be in the "safe hand". In this case, requester 120 may provide target protocol header 150 with provable information about the state of TrEE140, which may include provable keying material associated with TrEE140, and responses to the provable keying material may be encrypted.

In some cases, multiple different processes, such as provided by one or more trusted applications, may operate concurrently within a secure kernel, where each trusted application and secure kernel are considered to be TrEE140 (e.g., this is an example of a nested TrEE). In this case, each different trusted application may be associated with a session ID, a trusted application type, and/or other ID, which may be used to identify the respective trusted application within the security kernel (e.g., both denoted as TrEE 140). As will be described in more detail below, the response from target protocol header 150 may be narrowly targeted to the particular trusted application within TrEE140 identified in the request.

With TrEE140 targeting, there is no inherent need for a secure channel between the requester 120 and the target protocol header 150, as the requester 120 itself is not trusted by the response. However, it should be understood that a secure channel between the supplicant 120 and the target protocol header 150 may be added via the authentication operation 160, for example, to protect access to the request itself (the supplicant's intended secret), which may result in undesirable disclosure of information. After authentication at operation 160 or instead of authentication at operation 160, at operation 155, requestor 120 may send a request for one or more secrets or protected data to target protocol header 150 on behalf of TrEE140, e.g., for transmission to the TrEE. In some aspects, the request may be associated with TrEE140 or identify TrEE 140. Target protocol header 150 may determine whether TrEE140 is trustworthy. In one aspect, the authentication of the requester 120 may rely on a type of clean room (clean room) provisioning. In another aspect, authentication may rely on attestation.

Clean room provisioning may be used when, for example, the requester 120 device is brand new and reasonably assumed to be free of malware. An example process for transferring protected data to a TrEE associated with a requestor using cleanroom provisioning will be described in more detail below with reference to fig. 3. An example process for using attestation (e.g., an attestation service) to transfer protected data to a TrEE associated with a requestor will be described in more detail below with reference to fig. 4.

In either case, once TPH150 has authenticated requester 120, and/or established trustworthiness of TrEE140, TPH150 may authenticate and establish a secure communication channel with KMS115 at operation 165. In some aspects, KMS115 may include or be associated with any entity that maintains one or more secrets or protected data, such as permissions (licenses), permissions (permissions), passwords, and the like. Upon establishing a secure communication channel with KMS115, TPH150 may send a request for protected data at operation 170. The KMS115 may return the requested secret at operation 175. At operation 180, TPH150 may target secret(s) or protected data and send one or more secrets at TrEE 140.

In some aspects, the transfer of the protected data to TrEE140 at operation 180 may utilize at least one of the following data structures: an encrypted identity key that can be built around the TrEE identity or attestation process or attestation log; or a signed identity key in a nested TrEE example (e.g., a trusted application running on top of a secure kernel), which may also be built around the attestation process, as will be described in more detail below.

FIG. 1C illustrates another example system and process 100C for securely exchanging one or more secrets or protected data between a requestor 120 and a KMS115 on behalf of a trusted execution environment (TrEE) 140. The system 100c may be a specific example of the system 100b described above. In the system 100c, the target protocol header 150 may be a hosting service (HGS)150 a. In system 100c, HGS150a may receive key protector 190, for example, from cloud host 185 or other entity that may instantiate or otherwise control TrEE 140. In system 100c, requestor 120 may be associated with a virtual machine, for example, provided by cloud host 185. KP 190 may contain one or more aspects of the key protector described in related U.S. patent application #14/481,399 entitled "Secure Transport of encrypted Virtual Machines with Continuous Owner Access," filed 9/2014. KP 190 may contain one or more secrets, such as transport keys, available to TrEE 140. KP 190 may essentially encapsulate the transport key such that it is only accessible to a group of guardians (guardians) who are authorized to access the transport key. The KP 190 may be encrypted such that, in order to read the content of the KP 190 and retrieve the transport key, after authenticating with the KMS115 and establishing a secure communication channel with the KMS115 at operation 165, the HGS150a may request a decryption key from the KMS115 at operation 170 a. In response, the KMS115 may send the decryption key to the HGS at operation 175 a. HGS150a may then decrypt KP 190 using the decryption key and retrieve one or more secrets (e.g., transport keys) to send to TrEE 140. The HGS150a may then send the secret or transport key to the TrEE via one or more addressing techniques, which will be described in more detail below, at operation 180. In some aspects, TrEE140 may be addressed based on data from KP 190.

It should be understood that in some cases, the HGS150a and KMS115 may be one entity, such that no communication channel needs to be established between them, and no authentication is required.

In the system 100c, no authentication between the requester 120 and the HGS150a is required. As long as the cloud or fabric host 180 is healthy, it is not important which fabric host is in communication with the HGS150a as long as it is one of the servers in the fabric (which can be verified via attestation).

Fig. 3 illustrates an example process 300 for transferring protected data to a TrEE of a requestor, where the requestor is assumed to be trusted (e.g., free of malware). As used herein, a dashed line of blocks or operations in any figure indicates that the operation is optional, such that it may be omitted. The process 300 may utilize an encryption key associated with the TrEE, such as a public key of a public-private key pair (e.g., an asymmetric key pair) generated by the TrEE or a secure kernel of the requestor originating the TrEE. In other cases, the encryption key may be symmetric. As used herein, a security kernel may refer to any portion of a computing device associated with a higher level of security, as is known in the art.

In this case, TrEE140 may be started (launch) or opened (initial) at operation 302, and one or more private keys (e.g., private encryption keys) and corresponding public keys may be generated within TrEE140 at operation 304. The respective public key may then be registered with TPH150 and associated with the identity of the requestor and/or requesting device at operation 306. In some cases, TrEE 140's public key only needs to be registered once, so that process 300 may begin at operation 308 after public key registration. The supplicant 120 may then authenticate with the TPH150 at operation 308 via any known authentication technique. TPH150 may then look up a public key for transmitting the response to TrEE140, e.g., based on TrEE 140's registration public key, which may be associated with the identity of requestor 120. This process may be referred to as "clean room" provisioning because it can only be done safely when the requester 120 is in a known good or trustworthy state. In this example, certificate-based authentication, in which the requestor 120 sends a TrEE Health Certificate (THC) to the TPH150, is not required, as the requestor 120 is trustworthy. In the absence of ubiquitous attestation services, this is a viable option to verify that TPH150 is targeting the correct TrEE 140.

Subsequently, at operation 312, TPH150 may retrieve the protected data, e.g., from KMS115, for delivery to TrEE140, as described above. Using the TrEE public key accessed via operation 310, TPH150 may then construct a message at operation 314 for transmission to TrEE140 that includes the acquired protected data. TPH150 may send a message to requester 120 at operation 316.

Upon receipt of the message, requester 120 may forward it to TrEE140 at operation 318. Because the requestor 120 cannot access the TrEE's private key, the requestor 120 cannot decrypt the message to access the protected data. At operation 320, TrEE140 may use its private key to decrypt the message and access the protected data.

Fig. 4A illustrates an example process 400 for transferring protected data to a TrEE of an untrusted requester. The process 400 may utilize an encryption key associated with the TrEE, such as a public key of a public-private key pair generated by the TrEE or a secure kernel of the requestor originating the TrEE, such as in the case of a nested TrEE (which may be referred to herein as a trusted application). Process 400 may additionally or alternatively utilize a signing key of the secure kernel, which may be considered an external TrEE associated with a TrEE where trusted applications are nested or run on top of the secure kernel, which may be used to verify the public key of a key pair generated by the TrEE, as described in more detail below.

According to process 400, after initializing TrEE at operation 402, requester 120 may request an attestation report or statement from an attestation service at operation 406. FIG. 4B illustrates an example process for obtaining a certification statement or report from the certification service 424. In the example of fig. 4B, at operation 426, requestor 120 may create a attestation log (TCG log) containing the public key of TrEE140 (secure kernel) (IDK _ E) (trusted application) or the signature key of TrEE (IDK _ S). The requestor 120 may then present the TCG log to the attestation service 424 at operation 428. In some cases, TPH150 may indicate or requester 120 may select an attestation service trusted by TPH 150. At operation 430, the attestation service 424 can examine the TCG log and issue a TrEE Health Certificate (THC) based on the encryption key (IDK _ E) and/or the signing key (IDK _ S) of the TrEE140 (secure kernel). The attestation service 242 may then send the THC (also referred to herein as an attestation statement) back to the requestor 120 at operation 432.

After obtaining the attestation statement at operation 406, requester 120 may send the attestation statement and a request for protected data to TPH150 on behalf of TrEE140 at operation 408. The THC or attestation statement may contain the subject name (subject name) of the requestor 120 (used to create a binding between the requestor identity and the certificate established during authentication), and the key (e.g., encryption key or signature key) that the responder (TPH 150) should use when making the response.

In some aspects, a tamper-resistant identity, such as an Encryption Key (EK) of a Trusted Platform Module (TPM), is associated with the requestor 120. The attestation of the requestor 120 may be performed using the TPM EK, as is known in the art.

In some aspects, the TrEE may communicate to TPH150 via requestor 120 whether out-of-band or through an Issue Policy (IP) Object Identifier (OID), which may be part of the THC, whether the key is an encryption key or a signing key. As described above, the choice between which key to use may influence the choice of mechanism for constructing the response. Importantly, TPH150 does not require proof of possession of the private key supporting the certificate, simply because if a wrong certificate is given, the requestor 120 will not understand the response because it has no access to the corresponding private key.

Fig. 5A and 5B illustrate an example process 500 for transferring protected data to a nested TrEE of an untrusted requester. In some aspects, two or more tees may be nested such that one teee is contained in another teee. As described herein, a trusted application is a nested TrEE, which is contained in an external TrEE. In one example, the external TrEE may include a secure kernel of a trusted portion of the operating system, such as a particular memory partition associated with a virtual trust level, as described in more detail below with reference to fig. 6. The process 500 may be used when, for example, only the encryption key of the external TrEE (which in some cases may be the secure kernel of the machine that instantiates the trusted application) is available.

Process 500 may begin at operation 502, where requester 120 launches a trusted application with a "session identifier" decided by requester 120, which may include any type of identifier, such as content or data related to or identifying the trusted application is to operate on, content or data related to a user of the trusted application, etc. (e.g., "stream content application trusted application for playing 'a particular title'"). In one example, the session ID may be a 32 byte value. This value may be retained, read-only for the lifetime of the trusted application, and made available to the security kernel when receiving the target message to the trusted application. This value may be lost (not specified at process start-up), in which case the session ID may be assumed to be zero.

Subsequently, at operation 504, the supplicant 120 may authenticate with the TPH150 (which is optional as described above, but only in very limited circumstances, such as when there is indeed no difference between supplicants). One example where a binding between a TrEE (e.g., the TrEE's key) and the identity of the requestor is desired is, for example: playback of a content item, such as a movie, is limited by licensing or subscriber verification (e.g., NetFlix users want to obtain a license to play the movie, but NetFlix wants to ensure that it is the user (within their TrEE) that is receiving the movie license).

At operation 506, the requestor 120 may obtain an attestation statement from an attestation service trusted by the TPH150, such as in accordance with the process 406 described above with reference to fig. 4B. The requestor 120 may then present the attestation statement to the TPH150 at operation 508. It should be understood that in the clean room supply example described above, which may be suitable for use herein, no certification is required.

Upon receiving the attestation statement, TPH150 may verify the attestation statement (or, in the case of the clean room provisioning example above, look up the requestor's key based on its identity) at operation 510. At this point in the process 500, the requestor 120 knows which key to use to address the external TrEE. In some aspects, an indication that the key obtained from the attestation statement or request is an encryption key of an external TrEE or secure kernel (rather than an internal trusted person) may be included in the request or attestation statement or communicated to TPH150 in another manner or out-of-band, set as a default procedure, or the like. Subsequently, at operation 511, the TPH150 may obtain the protected data indicated in the request, such as one or more services holding licenses, passwords, permissions, and/or other information, for example, from the KMS115 or from any other entity holding the protected data.

From operation 512, the TPH150 may determine which trusted application type to target, e.g., based on the request or based on the TPH150 itself (e.g., each TPH150 may be specifically designed for a particular purpose or application, such as NetFlix). In examples utilizing KPs, such as described above with reference to 1C, the trusted application type may be encoded in the KP. In some other examples, the trusted application type may be set by default or hard-coded, such as in an implementation utilizing HGS150 a. In the HGS example, HGS150a may always target a Virtual Mode Security Process (VMSP) trusted application, the type of which may be hard coded (since KPs may not contain this information).

Upon determining the trusted application type to target, TPH150 may construct a message at operation 514 that includes the protected data to be sent to the TrEE. A more detailed example of operation 514 is depicted in fig. 5B.

In some aspects, operation 514 may further comprise operation 536, wherein TPH150 generates two random symmetric keys: a transmission key TX and an encapsulation key TW. Subsequently, at operation 538, the TPH150 may encrypt the TX using the public key in the THC (which is part of the attestation statement) (e.g., assuming that the THC is based on an encryption key, rather than a signature key). In some aspects, operation 538 may include encrypting TX with IDK of the host using RSA encryption and OAEP padding. In some aspects, TPH150 may verify the session ID of the trusted application at operation 540, e.g., to verify whether the trusted application is authorized or has the correct permissions to access the protected data (e.g., to pay for the online service or content item). In some cases, the session ID may include a trusted application type; however, in other cases, the trusted application type may be encoded in the KP or even hard-coded. TPH150 may then encrypt TW using TX and may concatenate the trusted application type and session ID of the trusted application and use as an "authentication tag" at operations 542 and 544. Note that the use of authentication tags is a artifact of the AES-GCM protocol; other encryption protocols may use different schemes with the same effect. The idea behind the authentication tag is to bind TW with trusted application types and session IDs so that they cannot be decoupled in transit by an attacker. There are a number of other ways in which this encryption can be achieved; AES-GCM is described herein as it provides this functionality itself, and is therefore advantageous.

The TPH150 may then send the encrypted authentication encryption of TX and TW to the supplicant 120 at operation 546. As shown in fig. 5A, after receiving message 516, which may be generated via the operations of fig. 5B and/or may include protected data encrypted in a similar manner as the TW, requester 120 may forward the message to the trusted application at operation 518. Since the trusted application cannot decrypt the message (it is attempting to reach TW), the trusted application may transmit the message to the secure kernel at operation 520. Alternatively, the requestor 120 may bypass the trusted application to send a response to the secure kernel and alert the trusted application with the new information when the secure kernel is decrypting TW.

The secure kernel may then decrypt TX using its private encryption key, then decrypt TW using TX, using the authentication tag to ensure that the correct trusted application type with the correct session ID requests decryption of the message at operation 522. If the validation tag is verified, the secure kernel may return TW to the trusted application at operation 524. The trusted application may then use the received TW to decrypt any other content (such as protected data) that the TW is encrypting, which may be of any size.

In some aspects, the security kernel may implement one or more processes, such as processes defined by one or more APIs, for receiving, decrypting, and transmitting targeted messages to the correct trusted application. The API may receive encrypted messages targeted to a particular trusted application and decrypt the TX using the private portion of the IDK (the secure kernel identity encryption key). The API may use the trusted application type and the connection that invokes the session ID of the trusted application as a token to construct its own authentication tag (the provided authentication tag cannot be used for obvious security reasons). The trusted application type and session ID may then be obtained. If the authentication is successful, the API may decrypt TW using TX. If the decryption is successful, the API may return TW to the trusted application.

In one example, the received message may include the following information: version number (e.g., 0); transport key encryption protocol ID (e.g., RSA 2048); transport key encryption pad ID (e.g., OAEP); an encapsulation key encryption protocol ID (e.g., AES-GCM); the length of the transmission key ciphertext; length of the encapsulation key authentication ticket (ignore); the length of the cipher text of the packaging key; and transmit key ciphertext, encapsulate key authentication tag (ignore), and encapsulate key ciphertext. It should be understood that this is but one of many ways in which messages may be constructed.

In some aspects, the system or one or more of the processes/systems of processes 100, 300, 400, or 500 described above may be implemented in a virtual machine or resource that implements a Virtual Security Mode (VSM). VSM and related concepts in the context of Virtual Machines are described in U.S. patent application #14/186,415 entitled "Virtual Secure Mode for Virtual Machines," filed on 21/2/2014. Fig. 6 illustrates a system or host operating system 600 that includes a VSM computing environment divided into different virtual trust levels VTL0610 and VTL 1615. System 600 may be a more specific implementation of one or more aspects of systems 100a, 100b, or 100c, such as cloud host 180, which includes a computing environment operating in a VSM. VTL0610 may include user mode 620 and normal kernel mode 630, and VTL1615 may include user mode 625 and secure kernel mode 635. The different VTLs may be provided by a hypervisor, e.g., a hypervisor running on top of physical compute components or virtual compute resources (e.g., one or more virtual machines) that interact and define VTLs 0610 and VTLs 1615 via restrictions on memory access by certain processes and the like. In the example shown, VTL1615 may be more secure than VTL0610, such that reading and/or writing data or code associated with VTL1 requires higher access. VTL0610 may correspond to requestor 120 and VTL1615 may correspond to TrEE 140. System 600 is described below as utilizing KP 700. However, it should be understood that this is given by way of example only; the system 600 may utilize the above-described attestation/authentication scheme without using KP to achieve a similar effect.

As described with reference to system 600, client application 650/VTL 0610 of host 600 may correspond to requestor 120, while VTL1615, and more specifically, security kernel 635 of VTL1615, may correspond to TrEE 140. In some aspects, trusted application 640 may correspond to a nested trusted application described with reference to process 500. In some aspects, system 600 may implement process 500 described above. In other cases, system 600 may implement processes 800 and/or 900 described below with reference to fig. 8 and 9, where the primary difference between processes 500 and 800 is the use of KPs to initialize trusted applications and the use of specific implementations of HGS150a in place of the more generic TPH 150.

As shown, one or more TrEE or trusted applications 640 may reside in the user mode 625 of the VTL 1615. In some aspects, one or more trusted applications 640 may be accessed or associated with by a Virtual Machine Security Process (VMSP) 645. Client operations, applications, programs, etc. 650 (clients) may operate in user mode 620 of VTL 0610. The server 655 residing in the user mode 625 of the VTL1615 may communicate with the client 650 via the RPC 660. As shown in the figure. Client 650 may request initiation of trusted application 640 to perform one or more security operations via one or more RPCs 660, e.g., utilizing VMSP 645. In other aspects, the server 655 may launch the trusted application 640 without receiving an explicit request from the client 650. In either case, the server 655 may initiate the trust condition 640, where a particular trusted application type identifies parameters of a trusted application and a session ID identifies a particular instance of the trusted application 640. In some aspects, the trusted application type may be initialized via a data structure that includes KP 405, such as described above with reference to system 100C of fig. 1C. An example data structure including a KP, such as KP 700, is shown in FIG. 7.

The data structure 700 may include a Key Protector (KP)705, KP 705 being a cryptographic encapsulation of an encryption key (here, the transmission key TK), as described in U.S. patent application #14/481,399 entitled "Secure Transport of encrypted virtual Machines with Continuous Owner Access", filed 9.2014. KP 705 ensures that only authorized entities are provided access to TK 710 and/or other protected data. TK 710, which is the key delivered to TrEE140, may be packaged with KP 705, or in some cases with a key or TW. TK 710 may be considered a high value secret. In some cases, the TK 710 may be decrypted at the KMS 115.

The data structure 700 may also include Virtual Machine Data (VMD)730, and the VMD 730 may include data for initializing a trusted application. VMD 730 may be encrypted using a suitable encryption technique, such as BitLocker available from microsoft corporation of Redmond Wash. Full Volume Encryption Key (FVEK)725 (which may be used to decrypt VMD 730 and may be generated by a virtual trusted platform Module (V)_TPM) Protection) state (725) is setEncrypted and stored with KP 705 as part of the metadata. In some aspects, the FVEK725 may be encrypted by a Volume Master Key (VMK) 720. V_TPMState 725 is itself encrypted using a key encapsulated by KP 705. In some aspects, V_TPMState 725 may be encrypted by TK 710 (a high value secret) and "seal" the data to PCR values (e.g., PCR7), such that if the PCR values are in an expected state, the TPM will allow access to (e.g., decrypt) the keying material. In this case, the TPM protector is a data structure that is fed into the TPM to unseal certain secrets if one or more PCRs are in an expected state. In other cases, a non-TPM protector may also be used.

Volume Master Key (VMK)720 may be represented by V_TPMState 725 is unsealed. V_TPMState 725 may be encrypted by TK 710 within KP 705. In some cases, VMK 720 may be a bitocker volume master key and may be marked as a low value secret.

Each field or block of KP 700 may also be described in terms of its encrypted content, such as encryption (key, data) shorthand:

VMD_DISKencryption (FVEK, ClearText disk data)

FVEK_DISKEncryption (VMK, FVEK)

VMK_DISKEncryption (VMK)

VTPM._DISKEncryption (TK, V)_TPM)

TK_DISKEncryption (KP, TK)

KP KPs are associated with VMs, and trusted applications never actually see

It is used. KP goes to KMS, which decrypts it and puts TK

Returning to the trusted application (via the targeting mechanism described above). TK decryption

vTPM, vTPM decapsulates the VMK to generate the FVEK.

In one example, KP 405, V_TPMState 415, VMK 420, and VMD 430 may be data stored on disk. V_TPMState 415 may be creating V_TPMIs initialized and can be guaranteed to be unique. For runtime uniqueness, e.g. of generated secrets or protected data, V_TPMRelying on the security of the RNG provided to it by the security kernel. Decrypting V using decrypted TK 710 at trusted application_TPMFollowing state 415, the remaining operations to access VMD 730 may be the same as or similar to those performed between the physical machine and the physical TPM. These operations may include V_TPMPerforming a measurement of VSM using V_TPMThe measurement unseals the VMK (resulting in the providing of FVEK725 to the operating system loader), and the operating system decrypts the VMD 730 using FVEK 725.

To launch a trusted application, client 650 may request and/or receive data structure 700. The client 650 may send the KP 705 or the entire data structure 700 to the TPH150 (or in some implementations, to the HGS150 a), and the TPH150 may communicate with the KMS115 to decrypt the TK 710. The TPH may then target TK 710 at a secure kernel 635 associated with trusted application 640 using IDK _ pub 665, e.g., via process 800 described below. Secure kernel 635 may obtain IDK _ pub and IDK _ pri at boot time. The secure kernel 635 may decrypt and return TK 710 to the server 655 using its private key 675 (e.g., IDK pri). Server 655 may then transmit TK 710 to trusted application 640. In some cases, secure kernel 635 may return TK 710 directly to trusted application 640. In some aspects, the protected data may be transmitted to trusted application 640 along with TK 710 and encrypted by TK 710. In this manner, trusted application 640 may decrypt the protected data using TK 710.

Fig. 8 illustrates an example process 800 for targeting a transport key and/or protected data encrypted by the transport key to a TrEE or a particular trusted application using the TrEE or trusted application's identity key. More specifically, process 800 illustrates a manner in which trusted applications are targeted via encryption keys of a secure kernel of the trusted applications.

The cloud-fabric host or host OS (e.g., host OS 600) performs a series of steps in order to receive the transport key. The cloud fabric host may first obtain a TrEE Health Certificate (THC), e.g., built around an encrypted identity key (IDK _ E) of a security kernel associated with the TrEE or trusted application, at operation 602, such as according to the process described above with reference to fig. 4B. In one aspect, operation 602 may include creating, by the host at boot time, a attestation log (TCG log) containing a public version of IDK _ E, a private portion of IDK _ E residing in a VSM Security Kernel (SK) associated with the trusted application. The attestation log may be presented to an Attestation Service (AS). The AS may examine the attestation log and issue to the host a THC built around IDK _ E (e.g., the public portion of the asymmetric key). In some aspects, similar to IDK _ E, a "signature identity key" (IDK _ S) may also be created and IDK _ S may have a separate THC built around it, as will be described in more detail below with reference to fig. 9. As described below, a solution to the key transport problem may be constructed using IDK _ E or IDK _ S.

When a new masked VM needs to be loaded, the host obtains the KP for the VM at operation 804 and initiates a dialog with a TPH (e.g., TPH 150) with the goal of injecting TK encrypted by the KP into the VMSP trusted application.

To exchange KPs for a TK, at operation 806, the host may present KPs and a "trusted application identity" and THC to a TPH, such as TPH 150. At operation 808, the cloud fabric host may also launch a trusted application or TrEE with a "session ID" derived from kp (kpsid). In some aspects, the received KP will form the basis for the session ID value by creating a SHA-2 hash thereon or utilizing other one-way functions. The TPH may examine the THC at operation 822 and communicate with a KMS (such as KMS 115) or other entity in possession or other entity that may access the protected data and/or the KP's decryption key to decrypt the KP to access the TK at operation 824. At operation 826, the TPH may use a special encryption structure to target the trusted application with the calculated KPSID, e.g., as described above with reference to process 500.

The requestor or client 650 may receive the response from the TPH and forward it to the trusted application with the given KPSID. At operation 810, the trusted application or server may require the VSM security kernel to decrypt the response and return it to the TK. The secure kernel checks the response, verifies if it targets a trusted application type and a session ID of the trusted application at operation 812, and returns only the key if there is a match at operation 818. Thus, if the TPH response ends in the wrong hand, it is cryptographically impossible to understand. Upon receiving the key, the host may decrypt the key and provide it to the TrEE at operation 820, at which point process 800 may end.

Fig. 9 illustrates another example process 900 for targeting a transport key and/or protected data encrypted by the transport key to a trusted application using a signing key of a secure kernel. More specifically, process 900 illustrates a manner in which a trusted application is targeted by its encryption key authenticated by the secure kernel's signing key.

Process 800 illustrates how a response is indirectly targeted at a trusted application by an identity encryption key that is shared between all trusted applications. However, another method may be used if the TrEE has a provable identity signing key. Here, each trusted application may generate its own encryption key pair and use IDK _ S to cause the secure kernel to verify the public key portion of the pair. Note that such authentication must also cryptographically bind the key to the trusted application type and the session ID of the trusted application:

Key_certification＝σIDK_S(Trustlet_Encryption_Key_Pub,

Trustlet_Type,Session_ID)

where σ IDK _ S represents a concatenation of its inputs () followed by a signature using a given key on these inputs.

In this case, the requestor presents the key of the trusted application, along with the THC and the key attestation, to the TPH, and the TPH responds by encrypting the transport key to the encryption key of the trusted application, as opposed to process 800 at operations 822 and 824.

In some aspects, a "security version number" (SVN) may also be used or indicated in key authentication to prevent other types of attacks to ensure that the TrEE is not an older and potentially vulnerable version. In some cases, when the secure kernel is certified but the internal trusted application is not certified (e.g., after the certification has been completed, the trusted application is loaded on demand), the SVN including the trusted application may instruct the TPH150 to deny targeting to older vulnerable trusted applications even if THC is not an issue.

One difference between the two methods of processes 800 and 900 is who enforces a binding between a trusted application or TrEE ID, a session ID, and a transport key: in process 800, it is the secure kernel, and in process 900, it is the TPH 150. Another major difference is how the response is constructed in an encrypted manner. In the former case, it is targeted to the secure kernel, which in turn decides which trusted application is allowed to see it, in which case the response is directly targeted to the trusted application, with the keys of the trusted application being authenticated by the keys of the secure kernel.

In some aspects, the techniques described above may be implemented to provide full credential isolation for a container. The basic problem is the same, so the container can request credentials from its host. The host can then request credentials from a certain KMS on behalf of the container. If the requested credential is returned to the host unencrypted (e.g., the credential arrives on demand and is not part of the container image), this may result in "deferred credential binding". This binding is valuable but not equal to credential isolation, so if the host is compromised, the credential is disclosed.

In one embodiment, a computing system comprises:

a processor; and

a memory communicatively coupled to the processor, the memory storing instructions that, when executed by the processor, cause the computing system to:

receiving a request for protected data and an attestation statement of a secure kernel from a potentially untrusted requestor associated with a nested TrEE, wherein the nested TrEE includes a trusted application running on top of the secure kernel, wherein the trusted application is associated with a trusted application ID;

encrypting the transport encryption key with a second encryption key derived from the attestation statement;

retrieving the protected data;

encrypting the protected data using the transport encryption key and an authentication tag, wherein the authentication tag binds the requestor with the trusted application ID; and

the encrypted transport encryption key, the encrypted protected data, and the encrypted authentication ticket are provided to the requestor.

2. The computing system of claim 1, wherein the trusted application ID comprises a trusted application type and a session ID. 2. The computing system of claim 1, wherein

In one embodiment, the second encryption key comprises a secure kernel encryption key.

In one embodiment, decrypting the encrypted protected data requires a private secure kernel encryption key corresponding to the secure kernel encryption key.

In one embodiment, the instructions include additional instructions that, when executed by the processor, cause the computing system to:

comparing the trusted application ID to a list of authorized trusted application IDs; and

the protected data is encrypted using the transport encryption key and the authentication tag only if the trusted application ID is associated with the list of authorized trusted application IDs.

In one embodiment, a method for delivering protected data to a nested trusted execution environment (TrEE) comprising a trusted application running on top of a secure kernel, wherein both the trusted application and the secure kernel are associated with a potentially untrusted requester, the method comprising:

receiving, by a target protocol header, a request for protected data and an attestation statement of a secure kernel from a potentially untrusted requestor associated with a nested TrEE, wherein a trusted application is associated with a trusted application ID;

retrieving, by the target protocol header, the protected data;

In one embodiment, the trusted application ID includes a trusted application type and a session ID.

In one embodiment, the method further comprises:

receiving, by the potentially untrusted requestor, the encrypted transport encryption key and the authenticated encrypted protected data; and

sending, by the potentially untrusted supplicant, the encrypted transport encryption key and the authenticated encrypted protected data to the secure kernel, wherein the secure kernel decrypts the transport key using a private second encryption key corresponding to the second encryption key and decrypts the protected data using the decrypted transport key.

In one embodiment, sending, by the potentially untrusted supplicant to the security kernel, the encrypted transport encryption key and the authenticated encrypted protected data comprises: sending the encrypted transport encryption key and the authenticated encrypted protected data to the trusted application, wherein the trusted application forwards the encrypted transport encryption key and the authenticated encrypted protected data to the security kernel.

In one embodiment, the secure kernel validates the authenticated encrypted protected data for the trusted application based on the trusted application type and the session ID, and sends the decrypted protected data to the trusted application based on the trusted application type and the session ID.

In one embodiment, the protected data includes an encapsulation key.

In one embodiment, the method further comprises:

comparing, by the target protocol header, the trusted application ID to a list of authorized trusted application IDs; and

the protected data is encrypted by the target protocol header using the transport encryption key and the authentication tag only if the trusted application ID is associated with the list of authorized trusted application IDs.

In one embodiment, a computer-readable storage medium includes instructions for delivering protected data to a nested trusted execution environment (TrEE) comprising a trusted application running above a secure kernel, the medium including instructions that, when executed on a computer system, cause the computer system to at least:

receiving a request for protected data and an attestation statement of a secure kernel from a potentially untrusted requestor associated with a nested TrEE, wherein a trusted application is associated with a trusted application ID;

retrieving the protected data;

In one embodiment, the protected data includes an encapsulation key.

In one embodiment, the instructions further include instructions that, when executed on the computing system, cause the computing system to at least:

As described below, the above-described techniques may be implemented on one or more computing devices or environments. FIG. 10 depicts an exemplary general-purpose computing environment in which some of the techniques described herein may be implemented, e.g., which may contain one or more of a requestor 120, a TrEE140, a TPH150, a host OS600, an AS 424, a KMS 115. The computing system environment 1002 is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the subject matter of the present disclosure. Neither should the computing environment 1002 be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment 1002. In some embodiments, the various depicted computing elements may include circuitry configured to instantiate specific aspects of the present disclosure. For example, the term circuitry used in this disclosure may include dedicated hardware components configured to perform functions through firmware or switches. In other example embodiments, the term circuitry may include a general purpose processing unit, memory, etc., configured by software instructions containing logic operable to perform functions. In example embodiments where circuitry includes a combination of hardware and software, an implementer may write source code containing logic and the source code can be compiled into machine readable code that can be processed by the general purpose processing unit. The selection of hardware versus software to implement a particular function is a design choice left to the implementer as those skilled in the art will appreciate that the prior art has evolved to the point where there is little difference between hardware, software, or a combination of hardware/software. More specifically, those skilled in the art will appreciate that a software process can be transformed into an equivalent hardware structure, and that a hardware structure can itself be transformed into an equivalent software process. Thus, the choice of hardware implementation versus software implementation is one of design choice and left to the implementer.

Computer 1002 (which may include any of a mobile device or smart phone, a tablet, a laptop, a desktop or collection of networked devices, cloud computing resources, etc.) typically includes a variety of computer-readable media. Computer readable media can be any available media that can be accessed by computer 1002 and includes both volatile and nonvolatile media, removable and non-removable media. The system memory 1022 includes computer storage media in the form of volatile and/or nonvolatile memory such as Read Only Memory (ROM)1023 and Random Access Memory (RAM) 1060. A basic input/output system 1024(BIOS), containing the basic routines that help to transfer information between elements within computer 1002, such as during start-up, is typically stored in ROM 1023. RAM 1060 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 1059. By way of example, and not limitation, FIG. 10 illustrates operating system 1025, application programs 1026, other program modules 1027, including a TrEE targeting application 1065, and program data 1028.

Computer 1002 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, FIG. 10 illustrates a hard disk drive 1038 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 1039 that reads from or writes to a removable, nonvolatile magnetic disk 1054, and an optical disk drive 1004 that reads from or writes to a removable, nonvolatile optical disk 1053 such as a CDROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the example operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 1038 is typically connected to the system bus 1021 through a non-removable memory interface such as interface 1034, and magnetic disk drive 1039 and optical disk drive 1004 are typically connected to the system bus 1021 by a removable memory interface, such as interface 1035 or 1036.

The drives and their associated computer storage media discussed above and illustrated in FIG. 10, provide storage of computer readable instructions, data structures, program modules and other data for the computer 1002. In FIG. 10, for example, hard disk drive 1038 is illustrated as storing operating system 1058, application programs 1057, other program modules 1056, and program data 1055. Note that these components can either be the same as or different from operating system 1025, application programs 1026, other program modules 1027, and program data 1028. Operating system 1058, application programs 1057, other program modules 1056, and program data 1055 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer 1002 through input devices such as a keyboard 1051 and pointing device 1052, commonly referred to as a mouse, trackball or touch pad. Other input devices (not shown) may include: a microphone, joystick, game pad, satellite dish, scanner, retinal scanner, or the like. These and other input devices are often connected to the processing unit 1059 through a user input interface 1036 that is coupled to the system bus 1021, but may be connected by other interface and bus structures, such as a parallel port, game port or a Universal Serial Bus (USB). A display 1042 or other type of display device is also connected to the system bus 1021 via an interface, such as a video interface 1032. In addition to the display, computers may also include other peripheral output devices such as speakers 1044 and printer 1043, which may be connected through an output peripheral interface 1033.

The computer 1002 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 1046. The remote computer 1046 may be a personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer 1002, although only a memory storage device 1047 has been illustrated in fig. 10. The logical connections depicted in FIG. 10 include a Local Area Network (LAN)1045 and a Wide Area Network (WAN)1049, but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, the internet, and cloud computing resources.

When used in a LAN networking environment, the computer 1002 is connected to the LAN1045 through a network interface or adapter 1037. When used in a WAN networking environment, the computer 1002 typically includes a modem 1005 or other means for establishing communications over the WAN 1049, such as the Internet. The modem 1005, which may be internal or external, may be connected to the system bus 1021 via the user input interface 1036 or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer 1002, or portions thereof, can be stored in the remote memory storage device. By way of example, and not limitation, fig. 10 illustrates remote application programs 1048 as residing on memory device 1047. It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.

In some aspects, other programs 1027 may include a TrEE targeting component or application 1065 that includes functionality as described above. In some cases, the TrEE targeting application 1065 may perform some or all of the operations of the processes 300, 400, 500, 800, and/or 900.

Each of the processes, methods, and algorithms described in the preceding sections may be implemented in, and automated in whole or in part by, code modules executed by one or more computers or computer processors. The code modules may be stored on any type of non-transitory computer-readable medium or computer storage device, such as a hard disk drive, solid state memory, optical disk, and the like. The processes and algorithms may be implemented in part or in whole in application specific circuitry. The results of the disclosed processes and process steps may be persistently or otherwise stored in any type of non-transitory computer storage device, such as, for example, volatile or non-volatile storage. The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and sub-combinations are intended to fall within the scope of the present disclosure. Additionally, certain method or process blocks may be omitted in some implementations. The methods and processes described herein are also not limited to any particular order, and the blocks or states associated therewith may be performed in other suitable orders. For example, the blocks or states described may be performed in an order different than the order specifically disclosed, or multiple blocks or states may be combined in a single block or state. The example blocks or states may be performed in series, in parallel, or in some other manner. Blocks or states may be added to or removed from the disclosed example embodiments. The example systems and components described herein may be configured differently than described. For example, elements may be added, removed, or rearranged in comparison to the disclosed example embodiments.

It will also be appreciated that various items are shown as being stored in memory or on storage while in use, and that these items, or portions thereof, may be transferred between memory and other storage devices for purposes of memory management and data integrity. Alternatively, in other embodiments, some or all of the software modules and/or systems may execute in memory on another device and communicate with the illustrated computing system via inter-computer communication. Further, in some embodiments, some or all of the systems and/or modules may be implemented or provided in other ways, such as at least partially in firmware and/or hardware, including but not limited to one or more Application Specific Integrated Circuits (ASICs), standard integrated circuits, controllers (e.g., by executing appropriate instructions and including microcontrollers and/or embedded controllers), Field Programmable Gate Arrays (FPGAs), Complex Programmable Logic Devices (CPLDs), and so forth. Some or all of the modules, systems, and data structures may also be stored on a computer-readable medium (e.g., as software instructions or structured data) to be read by an appropriate drive or via an appropriate connection, such as a hard disk, a memory, a network, or a portable media item. For purposes of the present specification and claims, the phrase "computer readable storage medium" and variations thereof does not include waves, signals, and/or other transitory and/or intangible communication media. The systems, modules, and data structures may also be transmitted as generated data signals (e.g., as part of a carrier wave or other analog or digital propagated signal) on a variety of computer-readable transmission media, including wireless-based and wired/cable-based media, and may take a variety of forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). In other embodiments, such a computer program product may take other forms as well. Accordingly, the present disclosure may be practiced with other computer system configurations.

Conditional language such as "can", "right", "can", "may", "e.g., (e.g)", as used herein, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or steps, unless expressly stated otherwise or otherwise understood in the context of the usage. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding (whether or not author entered or prompted) whether such features, elements, and/or steps are included or are to be performed in any particular embodiment. The terms "comprising," "including," "having," and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude other elements, features, acts, operations, and the like. Furthermore, the term "or" is used in its inclusive sense (and not in its exclusive sense), so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list.

While certain example embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions disclosed herein. Thus, nothing in the foregoing description is intended to imply that any particular feature, characteristic, step, module, or block is required or essential. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the methods and systems described herein may be made without departing from the spirit of the inventions disclosed herein. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of certain inventions disclosed herein.

Claims

1. A computing system, comprising:

a processor; and

encrypting a transport encryption key with a second encryption key derived from the attestation statement;

retrieving the protected data;

encrypting the protected data with the transport encryption key and an authentication tag, wherein the authentication tag binds the requestor with the trusted application ID; and

providing the encrypted transport encryption key, the encrypted protected data, and the encrypted authentication ticket to the requestor.

2. The computing system of claim 1, wherein the trusted application ID comprises a trusted application type and a session ID.

3. The computing system of claim 2, wherein the second encryption key comprises a secure kernel encryption key.

4. The computing system of claim 3, wherein decrypting the encrypted protected data requires a private secure kernel encryption key corresponding to the secure kernel encryption key.

5. The computing system of claim 1, wherein the instructions comprise additional instructions that, when executed by the processor, cause the computing system to:

encrypting the protected data with the transport encryption key and an authentication tag only if the trusted application ID is associated with the list of authorized trusted application IDs.

6. A method for delivering protected data to a nested trusted execution environment (TrEE) that includes a trusted application running above a secure kernel, wherein the trusted application and the secure kernel are both associated with a potentially untrusted requestor, the method comprising:

receiving, by a target protocol header, a request for protected data and an attestation statement of the secure kernel from the potentially untrusted requester associated with the nested TrEE, wherein the trusted application is associated with a trusted application ID;

retrieving, by the target protocol header, the protected data;

7. The method of claim 6, wherein the trusted application ID comprises a trusted application type and a session ID.

8. The method of claim 7, wherein the second encryption key comprises a secure kernel encryption key.

9. The method of claim 8, wherein decrypting the encrypted protected data requires a private secure kernel encryption key corresponding to the secure kernel encryption key.

10. The method of claim 7, further comprising:

receiving, by the potentially untrusted requestor, the encrypted transport encryption key and authenticated encrypted protected data; and

sending, by the potentially untrusted requestor, the encrypted transport encryption key and the authenticated encrypted protected data to the secure kernel, wherein the secure kernel decrypts the transport key with a second private encryption key corresponding to the second encryption key and decrypts the protected data with the decrypted transport key.

11. The method of claim 10, wherein sending, by the potentially untrusted requester to the security kernel, the encrypted transport encryption key and the authenticated encrypted protected data comprises: sending the encrypted transport encryption key and the authenticated encrypted protected data to the trusted application, wherein the trusted application forwards the encrypted transport encryption key and the authenticated encrypted protected data to the secure kernel.

12. The method of claim 10, wherein the security kernel validates that the authenticated encrypted protected data is for the trusted application based on the trusted application type and the session ID, and sends the decrypted protected data to the trusted application based on the trusted application type and the session ID.

13. The method of claim 6, wherein the protected data comprises an encapsulation key.

14. The method of claim 6, further comprising:

encrypting, by the target protocol header, the protected data with the transport encryption key and an authentication tag only if the trusted application ID is associated with the list of authorized trusted application IDs.

15. A computer-readable storage medium comprising instructions for delivering protected data to a nested trusted execution environment (TrEE) comprising a trusted application running above a secure kernel, the medium comprising instructions that, when executed on a computer system, cause the computer system to at least:

receiving a request for protected data and an attestation statement of the secure kernel from a potentially untrusted requestor associated with the nested TrEE, wherein the trusted application is associated with a trusted application ID;

retrieving the protected data;