Initial commit of garlic

ElGamal.h

@@ -12,23 +12,31 @@ namespace i2p
 {
 namespace crypto
 {
-	inline void ElGamalEncrypt (const uint8_t * key, const uint8_t * data, int len, uint8_t * encrypted)
+	inline void ElGamalEncrypt (const uint8_t * key, const uint8_t * data, int len, 
+		uint8_t * encrypted, bool zeroPadding = false) // 514 with padding and 512 without
 	{
 		CryptoPP::AutoSeededRandomPool rnd;		
 		CryptoPP::Integer y(key, 256), k(rnd, CryptoPP::Integer::One(), elgp-1);
 
-		a_exp_b_mod_c (elgg, k, elgp).Encode (encrypted, 256);
+		if (zeroPadding)
+		{
+			encrypted[0] = 0;
+			encrypted[257] = 0;
+		}	
+		a_exp_b_mod_c (elgg, k, elgp).Encode (zeroPadding ? encrypted + 1 : encrypted, 256);
 		uint8_t m[255];
 		m[0] = 0xFF;
 		memcpy (m+33, data, len);
 		CryptoPP::SHA256().CalculateDigest(m+1, m+33, 222);
 		a_times_b_mod_c (a_exp_b_mod_c (y, k, elgp), 
-			CryptoPP::Integer (m, 255), elgp).Encode (encrypted + 256, 256);
+			CryptoPP::Integer (m, 255), elgp).Encode (zeroPadding ? encrypted + 258 : encrypted + 256, 256);
 	}	
 
-	inline bool ElGamalDecrypt (const uint8_t * key, const uint8_t * encrypted, uint8_t * data)
+	inline bool ElGamalDecrypt (const uint8_t * key, const uint8_t * encrypted, 
+		uint8_t * data, bool zeroPadding = false)
 	{
-		CryptoPP::Integer x(key, 256), a(encrypted, 256), b(encrypted + 256, 256);
+		CryptoPP::Integer x(key, 256), a(zeroPadding? encrypted +1 : encrypted, 256), 
+			b(zeroPadding? encrypted + 258 :encrypted + 256, 256);
 		uint8_t m[255], hash[32];
 		a_times_b_mod_c (b, a_exp_b_mod_c (a, elgp - x - 1, elgp), elgp).Encode (m, 255);
 		CryptoPP::SHA256().CalculateDigest(hash, m+33, 222);

Garlic.cpp

@@ -0,0 +1,79 @@
+#include <inttypes.h>
+#include <map>
+#include <string>
+#include <cryptopp/modes.h>
+#include <cryptopp/aes.h>
+#include "RouterContext.h"
+#include "Timestamp.h"
+#include "ElGamal.h"
+#include "Garlic.h"
+
+namespace i2p
+{
+	I2NPMessage * WrapI2NPMessage (const uint8_t * encryptionKey, I2NPMessage * msg)
+	{
+		CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
+		// create ElGamal block
+		ElGamalBlock elGamal;
+		rnd.GenerateBlock (elGamal.sessionKey, 32); // session key
+		rnd.GenerateBlock (elGamal.preIV, 32); // Pre-IV
+		uint8_t iv[32]; // IV is first 16 bytes
+		CryptoPP::SHA256().CalculateDigest(iv, elGamal.preIV, 32);
+		
+		CryptoPP::CBC_Mode<CryptoPP::AES>::Encryption encryption;
+		encryption.SetKeyWithIV (elGamal.sessionKey, 32, iv); 
+		
+		I2NPMessage * m = NewI2NPMessage ();
+		uint8_t * buf = m->GetPayload () + 4; // 4 bytes for length
+		i2p::crypto::ElGamalEncrypt (encryptionKey, (uint8_t *)&elGamal, sizeof(elGamal), buf, true);
+		buf += 514;
+		size_t blockSize = 0;
+		*(uint16_t *)buf = 0; // tag count
+		blockSize += 2;
+		uint32_t * payloadSize = (uint32_t *)(buf + blockSize);
+		blockSize += 4;
+		uint8_t * payloadHash = buf + blockSize;
+		blockSize += 32;
+		buf[blockSize] = 0; // flag
+		blockSize++;
+		size_t len = CreateGarlicPayload (buf + blockSize, msg);
+		*payloadSize = htobe32 (len);
+		CryptoPP::SHA256().CalculateDigest(payloadHash, buf + blockSize, len);
+		blockSize += len;
+		size_t rem = blockSize % 16;
+		if (rem)
+			blockSize += (16-rem); //padding
+		encryption.ProcessData(buf, buf, blockSize);
+
+		*(uint32_t *)(m->GetPayload ()) = htobe32 (blockSize + 514);
+		m->len += blockSize + 514 + 4;	
+		FillI2NPMessageHeader (m, eI2NPGarlic);
+		DeleteI2NPMessage (msg);
+		return m;
+	}	
+
+	size_t CreateGarlicPayload (uint8_t * payload, I2NPMessage * msg)
+	{
+		uint64_t ts = i2p::util::GetMillisecondsSinceEpoch ();
+		size_t size = 0;
+		payload[size] = 1; // 1 clove
+		size++;
+		payload[size] = 0;//  delivery instructions flag
+		size++;
+		memcpy (payload + size, msg->GetBuffer (), msg->GetLength ());
+		size += msg->GetLength ();
+		*(uint32_t *)(payload + size) = htobe32 (1011); // CloveID
+		size += 4;
+		*(uint64_t *)(payload + size) = htobe64 (ts); // Expiration of clove
+		size += 8;
+		memset (payload + size, 0, 3); // certificate of clove
+		size += 3;
+		memset (payload + size, 0, 3); // certificate of message
+		size += 3;
+		*(uint32_t *)(payload + size) = htobe32 (2022); // MessageID
+		size += 4;
+		*(uint64_t *)(payload + size) = htobe64 (ts); // Expiration of message
+		size += 8;
+		return size;
+	}	
+}	

Garlic.h

@@ -0,0 +1,30 @@
+#ifndef GARLIC_H__
+#define GARLIC_H__
+
+#include <inttypes.h>
+#include "I2NPProtocol.h"
+
+namespace i2p
+{
+	enum GarlicDeliveryType 
+	{ 
+		eGarlicDeliveryTypeLocal = 0, 
+		eGarlicDeliveryTypeDestination = 1,
+		eGarlicDeliveryTypeRouter = 2,	
+		eGarlicDeliveryTypeTunnel = 3
+	};	
+
+#pragma pack(1)
+	struct ElGamalBlock
+	{
+		uint8_t sessionKey[32];
+		uint8_t preIV[32];
+		uint8_t padding[158];
+	};		
+#pragma pack()	
+	
+	I2NPMessage * WrapI2NPMessage (const uint8_t * encryptionKey, I2NPMessage * msg);
+	size_t CreateGarlicPayload (uint8_t * payload, I2NPMessage * msg);
+}	
+
+#endif