ECCPVerifyDSA¶
Verifies authenticity of the digital signature over a message digest (ECDSA).
Syntax¶
IppStatus ippsECCPVerifyDSA(const IppsBigNumState* pMsgDigest, const IppsBigNumState* pSignX, const IppsBigNumState* pSignY, IppECResult* pResult, IppsECCPState* pECC);
Include Files¶
ippcp.h
Parameters¶
pMsgDigest |
Pointer to the message digest msg. |
pSignX |
Pointer to the integer r of the digital signature. |
pSignY |
Pointer to the integer s of the digital signature. |
pResult |
Pointer to the digital signature verification result. |
pECC |
Pointer to the context of the elliptic cryptosystem. |
Description¶
The function verifies authenticity of the digital signature over a message digest msg. The signature consists of two large integers: r and s.
The scheme used to verify the signature is an elliptic curve analogue of the DSA scheme and assumes that the following cryptosystem key be hitherto set:
regPubKey |
Message sender’s regular public key. |
The regPubKey is set by the function ECCPSetKeyPair.
The result of the digital signature verification can take one of two possible values:
ippECValid |
Digital signature is valid. |
ippECInvalidSignature |
Digital signature is not valid. |
The call to the ECCPVerifyDSA function must be preceded by the call to the ECCPSignDSA function which computes the digital signature over the message digest msg and represents the signature with two numbers: r and s.
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.
Return Values¶
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 the value of pSignX or pSignY is less than 0. |
Related Information
Signing/Verification Using the Elliptic Curve Cryptography Functions over a Prime Finite Field