Developer Reference

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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
.

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