ECCBSignNR

Computes the digital signature over a message digest (the Nyberg-Rueppel scheme).

Syntax

IppStatus ippsECCBSignNR(const IppsBigNumState* pMsgDigest, const IppsBigNumState* pPrivate, IppsBigNumState* pSignX, IppsBigNumState* pSignY, IppsECCBState* pECC);

Parameters

pMsgDigest	Pointer to the message digest msg.
pPrivate	Pointer to the private key `privKey`.
pSignX	Pointer to the integer r of the digital signature.
pSignY	Pointer to the integer s of the digital signature.
pECC	Pointer to the context of the elliptic cryptosystem.

Description

This function is declared in the ippcp.h file.

The function computes two large numbers r and s which form the digital signature over a message digest msg.

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). The scheme that the given function uses assumes that the following cryptosystem keys are hitherto set up by the message sender:

regPrivKey	Regular private key.
ephPrivKey	Ephemeral private key.
ephPubKey	Ephemeral public key.

The keys can be generated and set up by the functions ECCBGenKeyPair and ECCBSetKeyPair with only requirement that the key regPrivKey be different from the key ephPrivKey.

The elliptic curve domain parameters must be hitherto defined by one of the functions: ECCBSet or ECCBSetStd.

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 one of the parameters pointed by pSignX or pSignY has a less memory size than the order n of the elliptic curve base point G.
ippStsEphemeralKeyErr	Indicates an error condition if the values of the ephemeral keys ephPrivKey and ephPubKey are not valid. (Either r = 0 or s = 0 is received as a result of the digital signature calculation).