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List of used keys

Roman Strobl edited this page Feb 28, 2019 · 6 revisions

PowerAuth Cryptography documentation has been moved to: https://developers.wultra.com/docs/latest/powerauth-crypto/List-of-Used-Keys

Please use the new developer portal to access documentation.


Following keys are used in the PowerAuth 2.0 cryptography scheme.

name created as purpose
KEY_DEVICE_PRIVATE ECDH - private key Generated on client to allow construction of KEY_MASTER_SECRET
KEY_DEVICE_PUBLIC ECDH - public key Generated on client to allow construction of KEY_MASTER_SECRET
KEY_SERVER_PRIVATE ECDH - private key Generated on server to allow construction of KEY_MASTER_SECRET
KEY_SERVER_PUBLIC ECDH - public key Generated on server to allow construction of KEY_MASTER_SECRET
KEY_SERVER_MASTER_PRIVATE ECDH - private key Stored on server, used to assure authenticity of KEY_DEVICE_PUBLIC while transferring from server to client
KEY_SERVER_MASTER_PUBLIC ECDH - public key Stored on client, used to assure authenticity of KEY_DEVICE_PUBLIC while transferring from server to client
ACTIVATION_OTP Random OTP A 16b random OTP generated during activation, AES encrypts/decrypts data sent from server to client and vice versa
KEY_MASTER_SECRET ECDH - pre-shared A key deduced using ECDH derivation, KEY_MASTER_SECRET = ECDH.phase(KEY_DEVICE_PRIVATE,KEY_SERVER_PUBLIC) = ECDH.phase(KEY_SERVER_PRIVATE,KEY_DEVICE_PUBLIC)
KEY_SIGNATURE_POSSESSION KDF derived key from KEY_MASTER_SECRET A signing key associated with the possession, factor deduced using KDF derivation with INDEX = 1, KEY_SIGNATURE_POSSESSION = KDF.expand(KEY_MASTER_SECRET, INDEX), used for subsequent request signing
KEY_SIGNATURE_KNOWLEDGE KDF derived key from KEY_MASTER_SECRET A key associated with the knowledge factor, deduced using KDF derivation with INDEX = 2, KEY_SIGNATURE_KNOWLEDGE = KDF.expand(KEY_MASTER_SECRET, INDEX), used for subsequent request signing
KEY_SIGNATURE_BIOMETRY KDF derived key from KEY_MASTER_SECRET A key associated with the biometry factor, deduced using KDF derivation with INDEX = 3, KEY_SIGNATURE_BIOMETRY = KDF.derive(KEY_MASTER_SECRET, INDEX), used for subsequent request signing
KEY_TRANSPORT KDF derived key from KEY_MASTER_SECRET A key deduced using KDF derivation with INDEX = 1000, KEY_TRANSPORT = KDF.expand(KEY_MASTER_SECRET, INDEX), used for encrypted data transport. This key is used as master transport key for end-to-end encryption key derivation.
KEY_TRANSPORT_PARTIAL KDF derived key from KEY_TRANSPORT using random 16B long SESSION_INDEX as index. A base key used for encrypted transport key derivation, deduced using KDF_INTERNAL derivation with INDEX = SESSION_INDEX = Generator.randomBytes(16), KEY_TRANSPORT_PARTIAL = KDF_INTERNAL.derive(KEY_TRANSPORT, INDEX)
KEY_TRANSPORT_ENCRYPTION KDF derived key from KEY_TRANSPORT_PARTIAL using random 16B long AD_HOC_INDEX as index. A key used for particular data encryption, deduced using KDF_INTERNAL derivation with INDEX = AD_HOC_INDEX = Generator.randomBytes(16), KEY_TRANSPORT_ENCRYPTION = KDF_INTERNAL.derive(KEY_TRANSPORT_PARTIAL, INDEX)
KEY_ENCRYPTION_VAULT KDF derived key from KEY_MASTER_SECRET A key deduced using KDF derivation with INDEX = 2000, KEY_ENCRYPTION_VAULT = KDF.expand(KEY_MASTER_SECRET, 2000), used for encrypting a vault that stores the secret data, such as KEY_DEVICE_PRIVATE.
KEY_ENCRYPTION_VAULT_TRANSPORT KDF derived key from KEY_TRANSPORT using CTR as index. A one-time key used for encrypted transport of the key vault encryption, deduced using KDF derivation with INDEX = CTR, KEY_ENCRYPTION_VAULT_TRANSPORT = KDF.derive(KEY_TRANSPORT, INDEX)