Developer Reference

Contents

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.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804