Developer Reference for Intel® Integrated Performance Primitives Cryptography 2019
Computes a shared secret field element by using the Diffie-Hellman scheme.
IppStatus ippsGFpECSharedSecretDH(const IppsBigNumState* pPrivateA, const IppsGFpECPoint* pPublicB, IppsBigNumState* pShare, IppsGFpECState* pEC, Ipp8u* pScratchBuffer);
ippcp.h
pPrivateA |
Pointer to your own private key privKey. |
pPublicB |
Pointer to the public key pubKey. |
pShare |
Pointer to the secret number bnShare. |
pEC |
Pointer to the context of the elliptic curve. |
pScratchBuffer |
Pointer to the scratch buffer. |
The function computes a secret number bnShare, which is a secret key shared between two participants of the cryptosystem.
In cryptography, metasyntactic names such as Alice as Bob are normally used as examples and in discussions and stand for participant A and participant B.
Both participants (Alice and Bob) use the cryptosystem for receiving a common secret point on the elliptic curve called a secret key. To receive a secret key, participants apply the Diffie-Hellman key-agreement scheme involving public key exchange. The value of the secret key entirely depends on participants.
According to the scheme, Alice and Bob perform the following operations:
Because the following equation is true privKeyA · privKeyB · G =privKeyB · privKeyA · G, the result of both calculations is the same, that is, the equation shareA = shareB is true. The secret point serves as a secret key.
Shared secret bnShare is the x-coordinate of the secret point on the elliptic curve.
The elliptic curve domain parameters must be hitherto defined by the functions: GFpECInitStd, GFpECInit, GFpECSet, or GFpECSetSubgroup.
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 to by pPublicB, pPrivateA, pShare, or pEC does not match the operation. |
ippStsRangeErr |
Indicates an error condition if the memory size of bnShare pointed to by pShare is less than the size of the GFp modulus that is base for the specified elliptic curve. |
ippStsShareKeyErr |
Indicates an error condition if the shared secret key is not valid. (For example, the shared secret key is invalid if the result of the secret point calculation is the point at infinity.) |