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AEAD/ChaCha20/Poly1305 decryption and SessionCreate prcessing

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orignal 2018-06-13 16:16:23 -04:00
parent ee0ae0b74b
commit 5447259e1a
5 changed files with 90 additions and 24 deletions
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23
libi2pd/Crypto.cpp
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@ -1062,9 +1062,9 @@ namespace crypto
// AEAD/ChaCha20/Poly1305
size_t AEADChaCha20Poly1305Encrypt (const uint8_t * msg, size_t msgLen, const uint8_t * ad, size_t adLen, const uint8_t * key, const uint8_t * nonce, uint8_t * buf, size_t len)
bool AEADChaCha20Poly1305 (const uint8_t * msg, size_t msgLen, const uint8_t * ad, size_t adLen, const uint8_t * key, const uint8_t * nonce, uint8_t * buf, size_t len, bool encrypt)
{
if (msgLen + 16 < len) return 0;
if (encrypt && msgLen + 16 < len) return 0;
// generate one time poly key
uint8_t polyKey[64];
memset(polyKey, 0, sizeof(polyKey));
@ -1072,6 +1072,7 @@ namespace crypto
// encrypt data
memcpy (buf, msg, msgLen);
chacha20 (buf, msgLen, nonce, key, 1);
// create Poly1305 message
std::vector<uint8_t> polyMsg(adLen + msgLen + 3*16);
size_t offset = 0;
@ -1084,7 +1085,7 @@ namespace crypto
rem = 16 - rem;
memcpy (polyMsg.data () + offset, padding, rem); offset += rem;
}
memcpy (polyMsg.data () + offset, buf, msgLen); offset += msgLen; // encrypted data
memcpy (polyMsg.data () + offset, encrypt ? buf : msg, msgLen); offset += msgLen; // encrypted data
rem = msgLen & 0x0F; // %16
if (rem)
{
@ -1095,9 +1096,19 @@ namespace crypto
htole64buf (polyMsg.data () + offset, adLen); offset += 8;
htole64buf (polyMsg.data () + offset, msgLen); offset += 8;
// calculate Poly1305 tag and write in after encrypted data
Poly1305HMAC ((uint32_t *)(buf + msgLen), (uint32_t *)polyKey, polyMsg.data (), offset);
return msgLen + 16;
if (encrypt)
{
// calculate Poly1305 tag and write in after encrypted data
Poly1305HMAC ((uint32_t *)(buf + msgLen), (uint32_t *)polyKey, polyMsg.data (), offset);
}
else
{
uint32_t tag[8];
// calculate Poly1305 tag
Poly1305HMAC (tag, (uint32_t *)polyKey, polyMsg.data (), offset);
if (memcmp (tag, msg + msgLen, 16)) return false; // compare with provided
}
return true;
}
// init and terminate