Computes a digital signature over a message digest.
IppStatus ippsECCPSignDSA(const IppsBigNumState* pMsgDigest, const IppsBigNumState* pPrivate, IppsBigNumState* pSignX, IppsBigNumState* pSignY, IppsECCPState* pECC);
pMsgDigest |
Pointer to the message digest msg to be digitally signed, that is, to be ecrypted with a private key. |
pPrivate |
Pointer to the signer's regular private key. |
pSignX |
Pointer to the integer r of the digital signature. |
pSignY |
Pointer to the integer s of the digital signature. |
pECC |
Pointer to the context of the elliptic cryptosystem. |
This function is declared in the ippcp.h file.
A message digest is a fixed size number derived from the original message with an applied hash function over the binary code of the message. The signer's private key and the message digest are used to create a signature.
A digital signature over a message consists of a pair of large numbers r and s which the given function computes.
The scheme used for computing a digital signature is analogue of the ECDSA scheme, an elliptic curve analogue of the DSA scheme. ECDSA assumes that the following keys are hitherto set by a message signer:
ephPrivKey |
Ephemeral private key. |
ephPubKey |
Ephemeral public key. |
The keys can be generated and set up by the unctions ECCPGenKeyPair and ECCPSetKeyPair with only requirement that the key regPrivKey be different from the key ephPrivKey.
The elliptic curve domain parameters must be hitherto defined by one of the functions: ECCPSet or ECCPSetStd.
For more information on digital signatures, please refer to the [ANSI] standard.
ippStsNoErr |
Indicates no error. Any other value indicates an error or warning. |
ippStsNullPtrErr |
Indicates an error condition if any of the specified pointers is NULL. |
ippStsContextMatchErr |
Indicates an error condition if one of the contexts pointed by pMsgDigest, pSignX, pSignY, or ECC is not valid. |
ippStsMessageErr |
Indicates an error condition if the value of msg pointed by pMsgDigest falls outside the range of [1, n-1] where n is the order of the elliptic curve base point G. |
ippStsRangeErr |
Indicates an error condition if one of the parameters pointed by pSignX or pSignY has a less memory size than the order n of the elliptic curve base point G. |
ippStsEphemeralKeyErr |
Indicates an error condition if the values of the ephemeral keys ephPrivKey and ephPubKey are not valid. (Either r = 0 or s = 0 is received as a result of the digital signature calculation). |
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