Visible to Intel only — GUID: GUID-DDEB0982-1BDC-461C-85D1-06DF81FC8A86
Visible to Intel only — GUID: GUID-DDEB0982-1BDC-461C-85D1-06DF81FC8A86
ECCPSignDSA
Computes a digital signature over a message digest.
Syntax
IppStatus ippsECCPSignDSA(const IppsBigNumState* pMsgDigest, const IppsBigNumState* pPrivate, IppsBigNumState* pSignX, IppsBigNumState* pSignY, IppsECCPState* pECC);
Include Files
ippcp.h
Parameters
pMsgDigest |
Pointer to the message digest msg to be digitally signed, that is, to be ecrypted with a private key. |
pPrivate |
Pointer to the signer’s regular private key. |
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
A message digest is a fixed size number derived from the original message with an applied hash function over the binary code of the message. The signer’s private key and the message digest are used to create a signature.
A digital signature over a message consists of a pair of large numbers r and s which the given function computes.
The scheme used for computing a digital signature is the ECDSA scheme, an elliptic curve analogue of the DSA scheme. ECDSA assumes that the following keys are hitherto set by a message signer:
regPrivKey |
Regular private key. |
ephPrivKey |
Ephemeral private key. |
ephPubKey |
Ephemeral public key. |
For security reasons, each signature must be generated with the unique ephemeral private key. Because of this, the function clears (sets to zero) the input ephemeral key before return. To generate and set up the keys before sign generation, call the ECCPGenKeyPair and ECCPSetKeyPair functions.
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 is negative, or the bit length is greater than the bit length of n, 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 memory size smaller 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). |
ippStsInvalidPrivateKey |
Indicates an error condition if the private key value does not belong to the [0, n-1] range, where n is the order of the elliptic curve base point G. |
Related Information
Signing/Verification Using the Elliptic Curve Cryptography Functions over a Prime Finite Field