Developer Reference

Contents

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.
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.
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.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.