Cryptoki: a cryptographic Token Interface
Diffie-Hellman mechanisms
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pkcs11-base-v2.40-cos01
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- 11.5.2. PKCS 3 Diffie-Hellman key derivation
11.5. Diffie-Hellman mechanisms11.5.1. PKCS #3 Diffie-Hellman key pair generationThe PKCS #3 Diffie-Hellman key pair generation mechanism, denoted CKM_DH_PKCS_KEY_PAIR_GEN, is a key pair generation mechanism based on Diffie-Hellman key agreement, as defined in PKCS #3. This is what PKCS #3 calls “phase I”. It does not have a parameter. The mechanism generates Diffie-Hellman public/private key pairs with a particular prime and base, as specified in the CKA_PRIME and CKA_BASE attributes of the template for the public key. If the CKA_VALUE_BITS attribute of the private key is specified, the mechanism limits the length in bits of the private value, as described in PKCS #3. Note that this version of Cryptoki does not include a mechanism for generating a prime and base. The mechanism contributes the CKA_CLASS, CKA_KEY_TYPE, and CKA_VALUE attributes to the new public key and the CKA_CLASS, CKA_KEY_TYPE, CKA_PRIME, CKA_BASE, and CKA_VALUE (and the CKA_VALUE_BITS attribute, if it is not already provided in the template) attributes to the new private key; other attributes required by the Diffie-Hellman public and private key types must be specified in the templates. For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of Diffie-Hellman prime sizes, in bits. 11.5.2. PKCS #3 Diffie-Hellman key derivationThe PKCS #3 Diffie-Hellman key derivation mechanism, denoted CKM_DH_PKCS_DERIVE, is a mechanism for key derivation based on Diffie-Hellman key agreement, as defined in PKCS #3. This is what PKCS #3 calls “phase II”. It has a parameter, which is the public value of the other party in the key agreement protocol, represented as a Cryptoki “Big integer” (i.e., a sequence of bytes, most-significant byte first). This mechanism derives a secret key from a Diffie-Hellman private key and the public value of the other party. It computes a Diffie-Hellman secret value from the public value and private key according to PKCS #3, and truncates the result according to the CKA_KEY_TYPE attribute of the template and, if it has one and the key type supports it, the CKA_VALUE_LEN attribute of the template. (The truncation removes bytes from the leading end of the secret value.) The mechanism contributes the result as the CKA_VALUE attribute of the new key; other attributes required by the key type must be specified in the template. The derived key inherits the values of the CKA_SENSITIVE, CKA_ALWAYS_SENSITIVE, CKA_EXTRACTABLE, and CKA_NEVER_EXTRACTABLE attributes from the base key. The values of the CKA_SENSITIVE and CKA_EXTRACTABLE attributes may be overridden in the template for the derived key, however. Of course, if the base key has the CKA_ALWAYS_SENSITIVE attribute set to TRUE, then the template may not specify that the derived key should have the CKA_SENSITIVE attribute set to FALSE; similarly, if the base key has the CKA_NEVER_EXTRACTABLE attribute set to TRUE, then the template may not specify that the derived key should have the CKA_EXTRACTABLE attribute set to TRUE. For this mechanism, the ulMinKeySize and ulMaxKeySize fields of the CK_MECHANISM_INFO structure specify the supported range of Diffie-Hellman prime sizes, in bits. Download 360.55 Kb. Share with your friends:
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