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I2P: End-to-End encrypted and anonymous Internet
https://i2pd.website/
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83 lines
2.5 KiB
83 lines
2.5 KiB
#include <openssl/rand.h> |
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#include <openssl/sha.h> |
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#include <openssl/hmac.h> |
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#include "Crypto.h" |
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#include "Ed25519.h" |
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#include "ChaCha20.h" |
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#include "Poly1305.h" |
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#include "NTCP2.h" |
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namespace i2p |
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{ |
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namespace transport |
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{ |
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NTCP2Session::NTCP2Session (std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter): |
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TransportSession (in_RemoteRouter, 30) |
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{ |
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} |
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NTCP2Session::~NTCP2Session () |
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{ |
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} |
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bool NTCP2Session::KeyDerivationFunction (const uint8_t * rs, const uint8_t * pub, uint8_t * derived) |
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{ |
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static const char protocolName[] = "Noise_XK_25519_ChaChaPoly_SHA256"; // 32 bytes |
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uint8_t h[64], ck[33]; |
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memcpy (ck, protocolName, 32); |
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SHA256 ((const uint8_t *)protocolName, 32, h); |
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// h = SHA256(h || rs) |
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memcpy (h + 32, rs, 32); |
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SHA256 (h, 64, h); |
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// h = SHA256(h || pub) |
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memcpy (h + 32, pub, 32); |
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SHA256 (h, 64, h); |
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// x25519 between rs and priv |
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uint8_t inputKeyMaterial[32]; |
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BN_CTX * ctx = BN_CTX_new (); |
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i2p::crypto::GetEd25519 ()->Mul (rs, m_ExpandedPrivateKey, inputKeyMaterial, ctx); // rs*priv |
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BN_CTX_free (ctx); |
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// temp_key = HMAC-SHA256(ck, input_key_material) |
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uint8_t tempKey[32]; unsigned int len; |
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HMAC(EVP_sha256(), ck, 32, inputKeyMaterial, 32, tempKey, &len); |
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// ck = HMAC-SHA256(temp_key, byte(0x01)) |
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inputKeyMaterial[0] = 1; |
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HMAC(EVP_sha256(), tempKey, 32, inputKeyMaterial, 1, ck, &len); |
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// derived = HMAC-SHA256(temp_key, ck || byte(0x02)) |
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ck[32] = 2; |
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HMAC(EVP_sha256(), tempKey, 32, ck, 33, derived, &len); |
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return true; |
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} |
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void NTCP2Session::CreateEphemeralKey (uint8_t * pub) |
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{ |
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uint8_t key[32]; |
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RAND_bytes (key, 32); |
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i2p::crypto::Ed25519::ExpandPrivateKey (key, m_ExpandedPrivateKey); |
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BN_CTX * ctx = BN_CTX_new (); |
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auto publicKey = i2p::crypto::GetEd25519 ()->GeneratePublicKey (m_ExpandedPrivateKey, ctx); |
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i2p::crypto::GetEd25519 ()->EncodePublicKey (publicKey, pub, ctx); |
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BN_CTX_free (ctx); |
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} |
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void NTCP2Session::SendSessionRequest (const uint8_t * iv, const uint8_t * rs) |
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{ |
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i2p::crypto::AESAlignedBuffer<32> x; |
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CreateEphemeralKey (x); |
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// encrypt X |
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i2p::crypto::CBCEncryption encryption; |
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encryption.SetKey (GetRemoteIdentity ()->GetIdentHash ()); |
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encryption.SetIV (iv); |
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encryption.Encrypt (2, x.GetChipherBlock (), x.GetChipherBlock ()); |
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// encryption key for next block |
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uint8_t key[32]; |
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KeyDerivationFunction (rs, x, key); |
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// options |
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uint8_t options[32]; |
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// TODO: fill 16 bytes options |
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i2p::crypto::Poly1305HMAC (((uint32_t *)options) + 4, (uint32_t *)key, options, 16); // calculate MAC first |
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i2p::crypto::chacha20 (options, 16, 0, key); // then encrypt |
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} |
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} |
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} |
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