Abstract: A computer system stores a probabilistic data structure generated based at least in part on a plurality of digital signatures generated based at least in part on a plurality of components of a data set. The computer system receives a digital signature for verification. An entry can verify the digital signature within the probabilistic data structure by verifying the digital signature against the probabilistic data structure.

Abstract: A computer system encodes a plurality of components of a data set into a probabilistic data structure and digitally signs the probabilistic data structure. The computer system provides the digital signature for the probabilistic data structure and the probabilistic data structure to various entities. An entity can verify an individual component of the data set within the probabilistic data structure by verifying the individual component against the probabilistic data structure and the digital signature of the probabilistic data structure.

Abstract: A system performs cryptographic operations utilizing information usable to verify validity of plaintext. To prevent providing information about a plaintext by providing the information usable to verify the validity of the plaintext, the system provides the information usable to verify validity of the plaintext to an entity on a condition that the entity is authorized to access the plaintext. The information usable to verify validity of the plaintext may be persisted in ciphertext along with the plaintext to enable the plaintext to be verified when decrypted.

Abstract: A trusted co-processor can provide a hardware-based observation point into the operation of a host machine owned by a resource provider or other such entity. The co-processor can be installed via a peripheral card on a fast bus, such as a PCI bus, on the host machine. The co-processor can execute malware detection software, and can use this software to analyze data and/or code obtained from the relevant resources of the host machine. The trusted co-processor can notify the customer or another appropriate entity of the results of the scan, such that an appropriate action can be taken if malware is detected. The results of the scan can be trusted, as malware will be unable to falsify such a notification or modify the operation of the trusted co-processor.

Abstract: A key distribution service operated by a signature authority distributes one-time-use cryptographic keys to one or more delegates that generate digital signatures on behalf of the signature authority. The key distribution service uses a root seed value to generate subordinate seeds. The subordinate seeds are used to generate a set of cryptographic keys. Hashes are generated for each key, and the hashes are arranged into a Merkle tree with a root hash controlled by the signature authority. In response to a request from a delegate, the signature authority provides a subordinate seed to the delegate. The delegate uses the subordinate seed to generate one or more cryptographic keys. The cryptographic keys are used to generate digital signatures which are verifiable up to the root hash of the Merkle tree. Additional subordinate seeds may be distributed to entities by the signature authority when appropriate.

Abstract: A host machine operated for a specific purpose can have restricted access to other components in a multi-tenant environment in order to provide for the security of the host machine. The access restriction can prevent the host machine from obtaining updates to critical system-level configurations, but such information can be obtained through a signed command received to an API for the host machine. The command can be signed by a quorum of operators, and the host machine can be configured to verify the signatures and the quorum before processing the command. The host machine can store the updates to ephemeral storage as well as persistent storage, such that upon a reboot or power cycle the host machine can operate with current configuration data.

Abstract: A signature authority generates revocable one-time-use keys that are able to generate digital signatures. The signature authority generates a set of one-time-use keys, where each one-time-use key has a secret key and a public key derived from a hash of the secret key. The signature authority generates one or more revocation values that, when published, proves that the signature authority has the authority to revoke corresponding cryptographic keys. The signature authority hashes the public keys and the revocation values and arranges the hashes in a hash tree where the root of the hash tree acts as a public key of the signature authority. In some implementations, the one-time-use cryptographic keys are generated from a tree of seed values, and a particular revocation value is linked to a particular seed value, allowing for the revocation of a block of one-time-use cryptographic keys associated with the particular seed.

Abstract: A service provider provides virtual computing services using a fleet of one or more host computer systems. Each of the host computer systems may be equipped with a trusted platform module (“TPM”). The service provider, the host computer systems, and the virtual computing environments generate attestations that prove the integrity of the system. The attestations are signed with a one-time-use cryptographic key that is verifiable against the public keys of the service provider, a host computer system, and a virtual computing environment. The public key of the host computer system is integrated into a hash tree that links the public key of the host computer system to the public key of the service provider. The public key of the virtual computing environment is signed using a one-time-use graphic key issued to the host computer system that hosts the virtual computing environment.

Abstract: A cryptographic key management service receives a request to import a first cryptographic key. In response to the request, the service creates a public cryptographic key and a private cryptographic key. The private cryptographic key is encrypted using a second cryptographic key to create an import key token. The import key token and the public cryptographic key are provided in response to the request. The service receives an encrypted first cryptographic key, which the service decrypts using the private cryptographic key to obtain the first cryptographic key. The service stores the first cryptographic key and enables its use for the performance of cryptographic operations.

Abstract: A signature authority generates a master seed value that is used as the root of a seed tree of subordinate nodes. Each subordinate node of the seed tree is generated from the value of its parent node using a cryptographic hash or one-way function. The signature authority selects subordinate seed values which are distributed to one or more key generators, each of which generates a set of one-time-use cryptographic keys. Each key generator generates a hash tree from its set of one-time-use cryptographic keys, and the root of its hash tree is returned to the signature authority. The signature authority integrates the hashes provided by the key generators into a comprehensive hash tree. The root of the comprehensive hash tree acts as a public key for the signature authority.

Abstract: Cryptographic keys are durably stored for an amount of time. A cryptographic key is encrypted so as to be decryptable using another cryptographic key that has a limited lifetime. The other cryptographic key can be used to decrypt the encrypted cryptographic key to restore the cryptographic key during the lifetime of the other cryptographic key. After the lifetime of the other cryptographic key, if a copy of the cryptographic key is lost (e.g., inadvertently and unrecoverably deleted from memory), the cryptographic key becomes irrecoverable.

Abstract: A tiered credentialing approach provides assurance to customers having virtual machines running in a remote environment that the virtual images for these machines are in a pristine state and running in a trusted execution environment. The environment can be divided into multiple subsystems, each having its own cryptographic boundary, secure storage, and trusted computing capabilities. A trusted, limited subsystem can handle the administrative tasks for virtual machines running on the main system of a host computing device. The limited system can receive a certificate from a certificate authority, and can act as a certificate authority to provide credentials to the main system. Upon an attestation request, the subsystems can provide attestation information using the respective credentials as well as the certificate chain. An entity having the appropriate credentials can determine the state of the system from the response and verify the state is as expected.

Abstract: Multiple communications that encode data are encrypted for transit from one entity to the other. An entity receiving the communications decrypts at least some of the communications to determine how to process the communications. As part of processing the communications, the entity receiving the communications provides at least some of the encrypted communications to a data storage system without reencrypting those communications.

Abstract: A client establishes an cryptographically protected communications session and determines information usable to distinguish the session from other sessions. The client digitally signs the information using a cryptographic key that is independent of the session to enable a server to check whether the information matches the session that it established and whether the digital signature is correct. The server may perform mitigating operations if either or both of the information or the digital signature is/are invalid.

Abstract: A trusted co-processor can provide a hardware-based observation point into the operation of a host machine owned by a resource provider or other such entity. The co-processor can be installed via a peripheral card on a fast bus, such as a PCI bus, on the host machine. The co-processor can execute malware detection software, and can use this software to analyze data and/or code obtained from the relevant resources of the host machine. The trusted co-processor can notify the customer or another appropriate entity of the results of the scan, such that an appropriate action can be taken if malware is detected. The results of the scan can be trusted, as malware will be unable to falsify such a notification or modify the operation of the trusted co-processor.

Abstract: A signature authority generates a master seed value that is used to generate a seed tree of subordinate nodes. Each subordinate node of the seed tree is generated from the value of its parent node using a cryptographic hash or one-way function. The signature authority selects subordinate seed values from the seed tree which are distributed to one or more subordinates, each of which generates a set of one-time-use cryptographic keys from the provided seed. Each subordinate generates a hash tree from its set of one-time-use cryptographic keys, and returns the root of its hash tree to the signature authority. The signature authority integrates the hashes provided by the key generators into a comprehensive hash tree, and the root of the hash tree acts as a public key for the signature authority.

Abstract: A host machine operated for a specific purpose can have restricted access to other components in a multi-tenant environment in order to provide for the security of the host machine. The access restriction can prevent the host machine from obtaining updates to critical system-level configurations, but such information can be obtained through a signed command received to an API for the host machine. The command can be signed by a quorum of operators, and the host machine can be configured to verify the signatures and the quorum before processing the command. The host machine can store the updates to ephemeral storage as well as persistent storage, such that upon a reboot or power cycle the host machine can operate with current configuration data.

Abstract: A requirement for a pseudo-random number is identified. A usage context corresponding to the requirement is determined from among a plurality of usage contexts. A cryptographic transformation function is applied to a first pseudo-random number obtained from a pseudo-random number generator. The transformation function meets a security criterion which is based on the usage context. A result of the function is used to fulfill the requirement.

Abstract: A cryptographic key management service receives a request to import a first cryptographic key. In response to the request, the service creates a public cryptographic key and a private cryptographic key. The private cryptographic key is encrypted using a second cryptographic key to create an import key token. The import key token and the public cryptographic key are provided in response to the request. The service receives an encrypted first cryptographic key, which the service decrypts using the private cryptographic key to obtain the first cryptographic key. The service stores the first cryptographic key and enables its use for the performance of cryptographic operations.

Abstract: Cryptographic keys are durably stored for an amount of time. A cryptographic key is encrypted so as to be decryptable using another cryptographic key that has a limited lifetime. The other cryptographic key can be used to decrypt the encrypted cryptographic key to restore the cryptographic key during the lifetime of the other cryptographic key. After the lifetime of the other cryptographic key, if a copy of the cryptographic key is lost (e.g., inadvertently and unrecoverably deleted from memory), the cryptographic key becomes irrecoverable.