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ECICSEncrypt added

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orignal 2017-10-30 16:16:21 -04:00
parent 63ae6850d3
commit 39c1c3567b
2 changed files with 40 additions and 0 deletions
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36
libi2pd/Crypto.cpp
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@ -372,6 +372,42 @@ namespace crypto
BN_CTX_free (ctx);
}
// ECICS
void ECICSEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx)
{
BN_CTX_start (ctx);
BIGNUM * q = BN_CTX_get (ctx);
EC_GROUP_get_order(curve, q, ctx);
int len = BN_num_bytes (q);
BIGNUM * k = BN_CTX_get (ctx);
BN_rand_range (k, q); // 0 < k < q
// point for shared secret
auto p = EC_POINT_new (curve);
EC_POINT_mul (curve, p, k, nullptr, nullptr, ctx);
BIGNUM * x = BN_CTX_get (ctx), * y = BN_CTX_get (ctx);
EC_POINT_get_affine_coordinates_GFp (curve, p, x, y, nullptr);
bn2buf (x, encrypted, len);
bn2buf (y, encrypted + len, len);
RAND_bytes (encrypted + 2*len, 256 - 2*len);
// ecryption key
EC_POINT_mul (curve, p, nullptr, key, k, ctx);
EC_POINT_get_affine_coordinates_GFp (curve, p, x, y, nullptr);
uint8_t keyBuf[64], shared[32];
bn2buf (x, keyBuf, len);
SHA256 (keyBuf, len, shared);
// create buffer
uint8_t m[256];
m[0] = 0xFF; m[255] = 0xFF;
memcpy (m+33, data, 222);
SHA256 (m+33, 222, m+1);
// encrypt
AES_KEY aesKey;
AES_set_encrypt_key (shared, 256, &aesKey);
AES_encrypt (m, encrypted + 256, &aesKey);
EC_POINT_free (p);
BN_CTX_end (ctx);
}
// HMAC
const uint64_t IPAD = 0x3636363636363636;
const uint64_t OPAD = 0x5C5C5C5C5C5C5C5C;

4
libi2pd/Crypto.h
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@ -52,6 +52,10 @@ namespace crypto
bool ElGamalDecrypt (const uint8_t * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx, bool zeroPadding = false);
void GenerateElGamalKeyPair (uint8_t * priv, uint8_t * pub);
// ECICS
void ECICSEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx); // 222 bytes data, 512 bytes encrypted
// HMAC
typedef i2p::data::Tag<32> MACKey;
void HMACMD5Digest (uint8_t * msg, size_t len, const MACKey& key, uint8_t * digest);