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session tag for ECIESx25519 sessions

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orignal 2020-01-21 14:40:23 -05:00
parent ccec3376ba
commit 6142e93252
4 changed files with 79 additions and 28 deletions
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51
libi2pd/ECIESX25519AEADRatchetSession.cpp
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@ -18,20 +18,20 @@ namespace garlic
uint8_t keydata[64];
i2p::crypto::HKDF (rootKey, k, 32, "KDFDHRatchetStep", keydata); // keydata = HKDF(rootKey, k, "KDFDHRatchetStep", 64)
// nextRootKey = keydata[0:31]
i2p::crypto::HKDF (keydata + 32, nullptr, 0, "TagAndKeyGenKeys", m_CK);
// ck = [sessTag_ck, symmKey_ck] = HKDF(keydata[32:63], ZEROLEN, "TagAndKeyGenKeys", 64)
i2p::crypto::HKDF (keydata + 32, nullptr, 0, "TagAndKeyGenKeys", m_KeyData.buf);
// [sessTag_ck, symmKey_ck] = HKDF(keydata[32:63], ZEROLEN, "TagAndKeyGenKeys", 64)
}
void RatchetTagSet::NextSessionTagRatchet ()
{
i2p::crypto::HKDF (m_CK, nullptr, 0, "STInitialization", m_CK); // [ck, sesstag_constant] = HKDF(sessTag_ck, ZEROLEN, "STInitialization", 64)
memcpy (m_SessTagConstant, m_CK + 32, 32);
i2p::crypto::HKDF (m_KeyData.GetSessTagCK (), nullptr, 0, "STInitialization", m_KeyData.buf); // [sessTag_ck, sesstag_constant] = HKDF(sessTag_ck, ZEROLEN, "STInitialization", 64)
memcpy (m_SessTagConstant, m_KeyData.GetSessTagConstant (), 32);
}
const uint8_t * RatchetTagSet::GetNextSessionTag ()
uint64_t RatchetTagSet::GetNextSessionTag ()
{
i2p::crypto::HKDF (m_CK, m_SessTagConstant, 32, "SessionTagKeyGen", m_CK); // [ck, tag] = HKDF(sessTag_chainkey, SESSTAG_CONSTANT, "SessionTagKeyGen", 64)
return m_CK + 32;
i2p::crypto::HKDF (m_KeyData.GetSessTagCK (), m_SessTagConstant, 32, "SessionTagKeyGen", m_KeyData.buf); // [sessTag_ck, tag] = HKDF(sessTag_chainkey, SESSTAG_CONSTANT, "SessionTagKeyGen", 64)
return m_KeyData.GetTag ();
}
@ -60,7 +60,7 @@ namespace garlic
bool ECIESX25519AEADRatchetSession::GenerateEphemeralKeysAndEncode (uint8_t * buf)
{
for (int i = 0; i < 5; i++)
for (int i = 0; i < 10; i++)
{
m_EphemeralKeys.GenerateKeys ();
if (i2p::crypto::GetElligator ()->Encode (m_EphemeralKeys.GetPublicKey (), buf))
@ -69,6 +69,17 @@ namespace garlic
return false;
}
uint64_t ECIESX25519AEADRatchetSession::CreateNewSessionTag () const
{
uint8_t tagsetKey[32];
i2p::crypto::HKDF (m_CK, nullptr, 0, "SessionReplyTags", tagsetKey, 32); // tagsetKey = HKDF(chainKey, ZEROLEN, "SessionReplyTags", 32)
// Session Tag Ratchet
RatchetTagSet tagsetNsr;
tagsetNsr.DHInitialize (m_CK, tagsetKey); // tagset_nsr = DH_INITIALIZE(chainKey, tagsetKey)
tagsetNsr.NextSessionTagRatchet ();
return tagsetNsr.GetNextSessionTag ();
}
bool ECIESX25519AEADRatchetSession::NewIncomingSession (const uint8_t * buf, size_t len, CloveHandler handleClove)
{
if (!GetOwner ()) return false;
@ -199,24 +210,20 @@ namespace garlic
return false;
}
MixHash (out + offset, 16); // h = SHA256(h || ciphertext)
if (GetOwner ())
GetOwner ()->AddECIESx25519SessionTag (CreateNewSessionTag (), shared_from_this ());
return true;
}
bool ECIESX25519AEADRatchetSession::NewSessionReplyMessage (const uint8_t * payload, size_t len, uint8_t * out, size_t outLen)
{
// we are Bob
uint8_t tagsetKey[32];
i2p::crypto::HKDF (m_CK, nullptr, 0, "SessionReplyTags", tagsetKey, 32); // tagsetKey = HKDF(chainKey, ZEROLEN, "SessionReplyTags", 32)
// Session Tag Ratchet
RatchetTagSet tagsetNsr;
tagsetNsr.DHInitialize (m_CK, tagsetKey); // tagset_nsr = DH_INITIALIZE(chainKey, tagsetKey)
tagsetNsr.NextSessionTagRatchet ();
auto tag = tagsetNsr.GetNextSessionTag ();
uint64_t tag = CreateNewSessionTag ();
size_t offset = 0;
memcpy (out + offset, tag, 8);
memcpy (out + offset, &tag, 8);
offset += 8;
if (!GenerateEphemeralKeysAndEncode (out + offset)) // bepk
{
@ -225,7 +232,7 @@ namespace garlic
}
offset += 32;
// KDF for Reply Key Section
MixHash (tag, 8); // h = SHA256(h || tag)
MixHash ((const uint8_t *)&tag, 8); // h = SHA256(h || tag)
MixHash (m_EphemeralKeys.GetPublicKey (), 32); // h = SHA256(h || bepk)
uint8_t sharedSecret[32];
m_EphemeralKeys.Agree (m_RemoteStaticKey, sharedSecret); // sharedSecret = x25519(besk, aepk)
@ -257,6 +264,12 @@ namespace garlic
return true;
}
bool ECIESX25519AEADRatchetSession::NewOutgoingSessionReply (const uint8_t * buf, size_t len, CloveHandler handleClove)
{
// TODO
return true;
}
std::shared_ptr<I2NPMessage> ECIESX25519AEADRatchetSession::WrapSingleMessage (std::shared_ptr<const I2NPMessage> msg)
{
auto m = NewI2NPMessage ();