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pass zero padding parameter to ECEIS encryption

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orignal 2018-03-07 16:08:44 -05:00
parent e58aaa3f32
commit 066f8863fd
3 changed files with 42 additions and 17 deletions
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47
libi2pd/Crypto.cpp
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@ -373,7 +373,7 @@ namespace crypto
}
// ECIES
void ECIESEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx)
void ECIESEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx, bool zeroPadding)
{
BN_CTX_start (ctx);
BIGNUM * q = BN_CTX_get (ctx);
@ -386,10 +386,19 @@ namespace crypto
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);
encrypted[0] = 0;
bn2buf (x, encrypted + 1, len);
bn2buf (y, encrypted + 1 + len, len);
RAND_bytes (encrypted + 1 + 2*len, 256 - 2*len);
if (zeroPadding)
{
encrypted[0] = 0;
bn2buf (x, encrypted + 1, len);
bn2buf (y, encrypted + 1 + len, len);
RAND_bytes (encrypted + 1 + 2*len, 256 - 2*len);
}
else
{
bn2buf (x, encrypted, len);
bn2buf (y, encrypted + len, len);
RAND_bytes (encrypted + 2*len, 256 - 2*len);
}
// ecryption key and iv
EC_POINT_mul (curve, p, nullptr, key, k, ctx);
EC_POINT_get_affine_coordinates_GFp (curve, p, x, y, nullptr);
@ -403,16 +412,21 @@ namespace crypto
memcpy (m+33, data, 222);
SHA256 (m+33, 222, m+1);
// encrypt
encrypted[257] = 0;
CBCEncryption encryption;
encryption.SetKey (shared);
encryption.SetIV (iv);
encryption.Encrypt (m, 256, encrypted + 258);
if (zeroPadding)
{
encrypted[257] = 0;
encryption.Encrypt (m, 256, encrypted + 258);
}
else
encryption.Encrypt (m, 256, encrypted + 256);
EC_POINT_free (p);
BN_CTX_end (ctx);
}
bool ECIESDecrypt (const EC_GROUP * curve, const BIGNUM * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx)
bool ECIESDecrypt (const EC_GROUP * curve, const BIGNUM * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx, bool zeroPadding)
{
bool ret = true;
BN_CTX_start (ctx);
@ -421,8 +435,16 @@ namespace crypto
int len = BN_num_bytes (q);
// point for shared secret
BIGNUM * x = BN_CTX_get (ctx), * y = BN_CTX_get (ctx);
BN_bin2bn (encrypted + 1, len, x);
BN_bin2bn (encrypted + 1 + len, len, y);
if (zeroPadding)
{
BN_bin2bn (encrypted + 1, len, x);
BN_bin2bn (encrypted + 1 + len, len, y);
}
else
{
BN_bin2bn (encrypted, len, x);
BN_bin2bn (encrypted + len, len, y);
}
auto p = EC_POINT_new (curve);
if (EC_POINT_set_affine_coordinates_GFp (curve, p, x, y, nullptr))
{
@ -439,7 +461,10 @@ namespace crypto
CBCDecryption decryption;
decryption.SetKey (shared);
decryption.SetIV (iv);
decryption.Decrypt (encrypted + 258, 256, m);
if (zeroPadding)
decryption.Decrypt (encrypted + 258, 256, m);
else
decryption.Decrypt (encrypted + 256, 256, m);
// verify and copy
uint8_t hash[32];
SHA256 (m + 33, 222, hash);