AEAD/Chacha20/Poly1305 encrypt multiple buffers

libi2pd/ChaCha20.cpp

@@ -50,44 +50,26 @@ void quarterround(uint32_t *x, int a, int b, int c, int d)
     x[c] += x[d]; x[b] = rotl32(x[b] ^ x[c],  7);
 }
 
-    struct State_t
-    {
-      State_t() {};
-      State_t(State_t &&) = delete;
-      
-      State_t & operator += (const State_t & other)
-      {
-        for(int i = 0; i < 16; i++)
-            data[i] += other.data[i];
-        return *this;
-      }
-
-      void Copy(const State_t & other)
-      {
-           memcpy(data, other.data, sizeof(uint32_t) * 16);
-      }
-      uint32_t data[16];
-    };
-
-    struct Block_t
-    {
-      Block_t() {};
-      Block_t(Block_t &&) = delete;
 
-      uint8_t data[blocksize];
+struct Block_t
+{
+  Block_t() {};
+  Block_t(Block_t &&) = delete;
 
-      void operator << (const State_t & st)
-      {
-        int i;
-        for (i = 0; i < 16; i++) 
-            u32t8le(st.data[i], data + (i << 2));
-      }
-    };
+  uint8_t data[blocksize];
+
+  void operator << (const Chacha20State & st)
+  {
+    int i;
+    for (i = 0; i < 16; i++) 
+        u32t8le(st.data[i], data + (i << 2));
+  }
+};
 
-void block(const State_t &input, Block_t & block, int rounds)
+void block(const Chacha20State &input, Block_t & block, int rounds)
 {
     int i;
-    State_t x;
+    Chacha20State x;
     x.Copy(input);
 
     for (i = rounds; i > 0; i -= 2) 
@@ -107,44 +89,41 @@ void block(const State_t &input, Block_t & block, int rounds)
 }
 } // namespace chacha
 
-
-
-
-
-void chacha20(uint8_t * buf, size_t sz, const uint8_t * nonce, const uint8_t * key, uint32_t counter)
-{
-    chacha::State_t state;
-    chacha::Block_t block;
-    size_t i, j;
-
-    state.data[0] = 0x61707865;
-    state.data[1] = 0x3320646e;
-    state.data[2] = 0x79622d32;
-    state.data[3] = 0x6b206574;
-
-    for (i = 0; i < 8; i++) 
-        state.data[4 + i] = chacha::u8t32le(key + i * 4);
-    
-
-    state.data[12] = counter;
-
-    for (i = 0; i < 3; i++) 
-        state.data[13 + i] = chacha::u8t32le(nonce + i * 4);
-
-    
-    for (i = 0; i < sz; i += chacha::blocksize) 
-    {
-        chacha::block(state, block, chacha::rounds);
-        state.data[12]++;
-        for (j = i; j < i + chacha::blocksize; j++) 
-        {
-            if (j >= sz) break;
-            buf[j] ^= block.data[j - i];
-        }
-    }
-
-}
-
+	void Chacha20Init (Chacha20State& state, const uint8_t * nonce, const uint8_t * key, uint32_t counter)
+	{
+		state.data[0] = 0x61707865;
+		state.data[1] = 0x3320646e;
+		state.data[2] = 0x79622d32;
+		state.data[3] = 0x6b206574;
+		for (size_t i = 0; i < 8; i++) 
+		    state.data[4 + i] = chacha::u8t32le(key + i * 4);
+		
+		state.data[12] = counter;
+		for (size_t i = 0; i < 3; i++) 
+		    state.data[13 + i] = chacha::u8t32le(nonce + i * 4);
+	}
+
+	void Chacha20Encrypt (Chacha20State& state, uint8_t * buf, size_t sz)
+	{
+		chacha::Block_t block;
+		for (size_t i = 0; i < sz; i += chacha::blocksize) 
+		{
+		    chacha::block(state, block, chacha::rounds);
+		    state.data[12]++;
+		    for (size_t j = i; j < i + chacha::blocksize; j++) 
+		    {
+		        if (j >= sz) break;
+		        buf[j] ^= block.data[j - i];
+		    }
+		}
+	}
+
+	void chacha20(uint8_t * buf, size_t sz, const uint8_t * nonce, const uint8_t * key, uint32_t counter)
+	{
+		Chacha20State state;
+		Chacha20Init (state, nonce, key, counter);
+		Chacha20Encrypt (state, buf, sz);		
+	}
 }
 }
 #endif

libi2pd/ChaCha20.h

@@ -9,6 +9,8 @@
 #define LIBI2PD_CHACHA20_H
 #include <cstdint>
 #include <cstring>
+#include <inttypes.h>
+#include <string.h>
 #include "Crypto.h"
 
 #if LEGACY_OPENSSL
@@ -19,10 +21,32 @@ namespace crypto
   const std::size_t CHACHA20_KEY_BYTES = 32;
   const std::size_t CHACHA20_NOUNCE_BYTES = 12;
 
+	struct Chacha20State
+	{
+		Chacha20State () {};
+		Chacha20State (Chacha20State &&) = delete;
+
+		Chacha20State & operator += (const Chacha20State & other)
+		{
+			for(int i = 0; i < 16; i++)
+				data[i] += other.data[i];
+			return *this;
+		}
+
+		void Copy(const Chacha20State & other)
+		{
+		   memcpy(data, other.data, sizeof(uint32_t) * 16);
+		}
+		uint32_t data[16];
+	};	
+
+	void Chacha20Init (Chacha20State& state, const uint8_t * nonce, const uint8_t * key, uint32_t counter);
+	void Chacha20Encrypt (Chacha20State& state, uint8_t * buf, size_t sz);
+
   /** encrypt buf in place with chacha20 */
   void chacha20(uint8_t * buf, size_t sz, const uint8_t * nonce, const uint8_t * key, uint32_t counter=1);
 
-}
+} 
 }
 #endif
 

libi2pd/Crypto.cpp

@@ -1172,6 +1172,55 @@ namespace crypto
 		return ret;
 	}
 
+	void AEADChaCha20Poly1305Encrypt (std::vector<std::pair<void*, std::size_t> >& bufs, const uint8_t * key, const uint8_t * nonce, uint8_t * mac)
+	{
+		if (bufs.empty ()) return;
+#if LEGACY_OPENSSL
+		// generate one time poly key
+		uint64_t polyKey[8];
+		memset(polyKey, 0, sizeof(polyKey));
+		chacha20 ((uint8_t *)polyKey, 64, nonce, key, 0);
+		Poly1305 polyHash (polyKey);
+		// encrypt buffers	
+		Chacha20State state;
+		Chacha20Init (state, nonce, key, 1);	
+		size_t size = 0;
+		for (auto& it: bufs)
+		{
+			Chacha20Encrypt (state, (uint8_t *)it.first, it.second);
+			polyHash.Update ((uint8_t *)it.first, it.second); // after encryption
+			size += it.second;
+		}
+		// padding
+		uint8_t padding[16]; 
+		memset (padding, 0, 16);
+		auto rem = size & 0x0F; // %16
+		if (rem)
+		{
+			// padding2
+			rem = 16 - rem;
+			polyHash.Update (padding, rem);		
+		}
+		// adLen and msgLen
+		// adLen is always zero
+		htole64buf (padding + 8, size);
+		polyHash.Update (padding, 16);	
+		// MAC
+		polyHash.Finish ((uint64_t *)mac);
+#else
+		int outlen = 0;
+		EVP_CIPHER_CTX *ctx = EVP_CIPHER_CTX_new ();
+		EVP_EncryptInit_ex(ctx, EVP_chacha20_poly1305(), 0, 0, 0);
+		EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_IVLEN, 12, 0);
+		EVP_EncryptInit_ex(ctx, NULL, NULL, key, nonce);
+		for (auto& it: bufs)	
+			EVP_EncryptUpdate(ctx, (uint8_t *)it.first, &outlen, (uint8_t *)it.first, it.second);
+		EVP_EncryptFinal_ex(ctx, NULL, &outlen);
+		EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_GET_TAG, 16, mac);
+		EVP_CIPHER_CTX_free (ctx);
+#endif		
+	}
+
 // init and terminate
 
 /*	std::vector <std::unique_ptr<std::mutex> >  m_OpenSSLMutexes;

libi2pd/Crypto.h

@@ -3,6 +3,7 @@
 
 #include <inttypes.h>
 #include <string>
+#include <vector>
 #include <openssl/bn.h>
 #include <openssl/dh.h>
 #include <openssl/aes.h>
@@ -282,6 +283,8 @@ namespace crypto
 // AEAD/ChaCha20/Poly1305
 	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); // msgLen is len without tag
 
+	void AEADChaCha20Poly1305Encrypt (std::vector<std::pair<void*, std::size_t> >& bufs, const uint8_t * key, const uint8_t * nonce, uint8_t * mac); // encrypt multiple buffers with zero ad
+
 // init and terminate
 	void InitCrypto (bool precomputation);
 	void TerminateCrypto ();

tests/test-aeadchacha20poly1305.cpp

@@ -51,4 +51,10 @@ int main ()
 	uint8_t buf1[114];
 	assert (i2p::crypto::AEADChaCha20Poly1305 (buf, 114, ad, 12, key, nonce, buf1, 114, false));
 	assert (memcmp (buf1, text, 114) == 0);
+	// test encryption of multiple buffers
+	memcpy (buf, text, 114);
+	std::vector<std::pair<void*, std::size_t> > bufs{ std::make_pair (buf, 114) };  
+	i2p::crypto::AEADChaCha20Poly1305Encrypt (bufs, key, nonce, buf + 114);
+	i2p::crypto::AEADChaCha20Poly1305 (buf, 114, nullptr, 0, key, nonce, buf1, 114, false);
+	assert (memcmp (buf1, text, 114) == 0);
 }