Visible to Intel only — GUID: GUID-B3C83BC5-910F-4820-8557-824274E20181
Visible to Intel only — GUID: GUID-B3C83BC5-910F-4820-8557-824274E20181
GFpECVerifyNR
Verifies authenticity of the digital signature over a message digest (the Nyberg-Rueppel scheme).
Syntax
IppStatus ippsGFpECVerifyNR(onst IppsBigNumState* pMsgDigest, const IppsGFpECPoint* pRegPublic, const IppsBigNumState* pSignR, const IppsBigNumState* pSignS, IppECResult* pResult, IppsGFpECState* pEC, Ipp8u* pScratchBuffer);
Include Files
ippcp.h
Parameters
pMsgDigest |
Pointer to the message digest msg. |
pRegPublic |
Pointer to the signer’s regular public key. |
pSignR |
Pointer to the integer r of the digital signature. |
pSignS |
Pointer to the integer s of the digital signature. |
pResult |
Pointer to the digital signature verification result. |
pEC |
Pointer to the context of the elliptic curve. |
pScratchBuffer |
Pointer to the scratch buffer of size produced by ippsGFpECScratchBufferSize. |
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 compute the digital signature is an elliptic curve analogue of the El-Gamal Digital Signature scheme with the message recovery (the Nyberg-Rueppel signature scheme).
You can get the message sender’s regular public key regPubKey by calling the function GFpECPublicKey.
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 GFpECVerifyNR function must be preceded by a call to the GFpECSignNR 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 the functions: GFpECInitStd, GFpECInit, GFpECSet, or GFpECSetSubgroup.
For more information on digital signatures, please refer to the ANSI standard.
The ippsGFpECScratchBufferSize function should be called with nScalars equal to at least 2 to get the valid pScratchBuffer.
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 any of the contexts pointed to by pMsgDigest, pRegPublic, pSignR, pSignS, or pEC does not match the operation. |
ippStsMessageErr |
Indicates an error condition if the value of msg pointed to 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 any of the parameters pointed to by pSignR or pSignS is negative. |
ippStsOutOfRangeErr |
Indicates an error condition if the public key point does not belong to the finite field over which the elliptic curve is initialized. |
ippStsNotSupportedModeErr |
Indicates an error condition if the finite field GFp under the elliptic curve is not prime. |