Example of Using RSA Primitive Functions

Use of DLPSignDSA and DLPVerifyDSA

//

// known domain parameters

//

static const int M = 512; // DSA system bitsize

static const int L = 160; // DSA order  bitsize

static

BigNumber P("0x8DF2A494492276AA3D25759BB06869CBEAC0D83AFB8D0CF7" \

            "CBB8324F0D7882E5D0762FC5B7210EAFC2E9ADAC32AB7AAC" \

            "49693DFBF83724C2EC0736EE31C80291");

static

BigNumber Q("0xC773218C737EC8EE993B4F2DED30F48EDACE915F");

static

BigNumber G("0x626D027839EA0A13413163A55B4CB500299D5522956CEFCB" \

            "3BFF10F399CE2C2E71CB9DE5FA24BABF58E5B79521925C9C" \

            "C42E9F6F464B088CC572AF53E6D78802");

//

// known DSA regular key pair

//

static

BigNumber X("0x2070B3223DBA372FDE1C0FFC7B2E3B498B260614");

static

BigNumber Y("0x19131871D75B1612A819F29D78D1B0D7346F7AA77BB62A85" \

            "9BFD6C5675DA9D212D3A36EF1672EF660B8C7C255CC0EC74" \

            "858FBA33F44C06699630A76B030EE333");

int DSAsign_verify_sample(void)

{

   // DLP context

   IppsDLPState *DLPState = newDLP(M, L);

   // set up DLP crypto system

   ippsDLPSet(P, Q, G, DLPState);

  // message

   Ipp8u message[] = "abc";

   // compute message digest to be signed

   Ipp8u md[SHA1_DIGEST_LENGTH/8];

   ippsSHA1MessageDigest(message, sizeof(message)-1, md);

   BigNumber digest(0, BITS_2_WORDS(SHA1_DIGEST_LENGTH));

   ippsSetOctString_BN(md, SHA1_DIGEST_LENGTH/8, digest);

   // generate ephemeral key pair (ephX,ephY)

   BigNumber ephX(0, BITS_2_WORDS(L));

   BigNumber ephY(0, BITS_2_WORDS(M));

   IppsPRNGState* pRand = newPRNG();

   ippsDLPGenKeyPair(ephX, ephY, DLPState, ippsPRNGen, pRand);

   deletePRNG(pRand);

   //

   // generate signature

   //

   BigNumber signR(0, BITS_2_WORDS(L));      // R and S signature's component

   BigNumber signS(0, BITS_2_WORDS(L));

   ippsDLPSetKeyPair(ephX, ephY, DLPState);  // set up ephemeral keys

   ippsDLPSignDSA(digest, X,                 // sign digest

                  signR, signS,

                  DLPState);

   //

   // verify signature

   //

   ippsDLPSetKeyPair(0, Y, DLPState);        // set up regular public key

	IppDLResult result;

	ippsDLPVerifyDSA(digest, signR,signS,     // verify

                    &result, DLPState);

   deleteDLP(DLPState);

   return result==ippDLValid;

}