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use ElGamalEncrypt

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This commit is contained in:
orignal 2016-12-20 14:10:14 -05:00
parent ffaabe8674
commit 9da984b866
4 changed files with 11 additions and 35 deletions
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24
Crypto.cpp
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@ -272,10 +272,9 @@ namespace crypto
}
// ElGamal
ElGamalEncryption::ElGamalEncryption (const uint8_t * key)
void ElGamalEncrypt (const uint8_t * key, const uint8_t * data, uint8_t * encrypted, bool zeroPadding)
{
ctx = BN_CTX_new ();
BN_CTX * ctx = BN_CTX_new ();
// select random k
BIGNUM * k = BN_new ();
#if defined(__x86_64__)
@ -284,6 +283,7 @@ namespace crypto
BN_rand (k, ELGAMAL_SHORT_EXPONENT_NUM_BITS, -1, 1); // short exponent of 226 bits
#endif
// calculate a
BIGNUM * a;
if (g_ElggTable)
a = ElggPow (k, g_ElggTable, ctx);
else
@ -295,21 +295,10 @@ namespace crypto
BIGNUM * y = BN_new ();
BN_bin2bn (key, 256, y);
// calculate b1
b1 = BN_new ();
BIGNUM * b1 = BN_new ();
BN_mod_exp (b1, y, k, elgp, ctx);
BN_free (y);
BN_free (k);
}
ElGamalEncryption::~ElGamalEncryption ()
{
BN_CTX_free (ctx);
BN_free (a);
BN_free (b1);
}
void ElGamalEncryption::Encrypt (const uint8_t * data, uint8_t * encrypted, bool zeroPadding) const
{
// create m
uint8_t m[255];
m[0] = 0xFF;
@ -319,6 +308,7 @@ namespace crypto
BIGNUM * b = BN_new ();
BN_bin2bn (m, 255, b);
BN_mod_mul (b, b1, b, elgp, ctx);
BN_free (b1);
// copy a and b
if (zeroPadding)
{
@ -333,8 +323,10 @@ namespace crypto
bn2buf (b, encrypted + 256, 256);
}
BN_free (b);
BN_free (a);
BN_CTX_free (ctx);
}
bool ElGamalDecrypt (const uint8_t * key, const uint8_t * encrypted,
uint8_t * data, bool zeroPadding)
{