GFpECVerifySM2

Verifies authenticity of a digital signature over a message digest using the SM2 scheme.

Syntax

IppStatus ippsGFpECVerifySM2(const 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, represented as integer big numbers r and s, over a message digest msg. The digital signature over the message digest msg must be computed using the SM2 scheme SM2 by to the GFpECSignSM2 function.

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 these values:

ippECValid	Digital signature is valid.
ippECInvalidSignature	Digital signature is not valid.

The elliptic curve domain parameters must be hitherto defined by the functions: GFpECInitStd, GFpECInit, GFpECSet, or GFpECSetSubgroup.

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.