pass zero padding parameter to ECEIS encryption

libi2pd/Crypto.cpp

@@ -373,7 +373,7 @@ namespace crypto
 	}
 
 // ECIES
-	void ECIESEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx)
+	void ECIESEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx, bool zeroPadding)
 	{
 		BN_CTX_start (ctx);
 		BIGNUM * q = BN_CTX_get (ctx);
@@ -386,10 +386,19 @@ namespace crypto
 		EC_POINT_mul (curve, p, k, nullptr, nullptr, ctx);
 		BIGNUM * x = BN_CTX_get (ctx), * y = BN_CTX_get (ctx);
 		EC_POINT_get_affine_coordinates_GFp (curve, p, x, y, nullptr);
-		encrypted[0] = 0;
-		bn2buf (x, encrypted + 1, len);
-		bn2buf (y, encrypted + 1 + len, len);
-		RAND_bytes (encrypted + 1 + 2*len, 256 - 2*len);
+		if (zeroPadding)
+		{
+			encrypted[0] = 0;
+			bn2buf (x, encrypted + 1, len);
+			bn2buf (y, encrypted + 1 + len, len);
+			RAND_bytes (encrypted + 1 + 2*len, 256 - 2*len);
+		}	
+		else
+		{
+			bn2buf (x, encrypted, len);
+			bn2buf (y, encrypted + len, len);
+			RAND_bytes (encrypted + 2*len, 256 - 2*len);
+		}
 		// ecryption key and iv
 		EC_POINT_mul (curve, p, nullptr, key, k, ctx);
 		EC_POINT_get_affine_coordinates_GFp (curve, p, x, y, nullptr);
@@ -403,16 +412,21 @@ namespace crypto
 		memcpy (m+33, data, 222);
 		SHA256 (m+33, 222, m+1);
 		// encrypt
-		encrypted[257] = 0;
 		CBCEncryption encryption;
 		encryption.SetKey (shared);
 		encryption.SetIV (iv);
-		encryption.Encrypt (m, 256, encrypted + 258);
+		if (zeroPadding)
+		{
+			encrypted[257] = 0;
+			encryption.Encrypt (m, 256, encrypted + 258);
+		}
+		else
+			encryption.Encrypt (m, 256, encrypted + 256);
 		EC_POINT_free (p);
 		BN_CTX_end (ctx);
 	}
 
-	bool ECIESDecrypt (const EC_GROUP * curve, const BIGNUM * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx)
+	bool ECIESDecrypt (const EC_GROUP * curve, const BIGNUM * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx, bool zeroPadding)
 	{
 		bool ret = true;
 		BN_CTX_start (ctx);
@@ -421,8 +435,16 @@ namespace crypto
 		int len = BN_num_bytes (q);
 		// point for shared secret
 		BIGNUM * x = BN_CTX_get (ctx), * y = BN_CTX_get (ctx);
-		BN_bin2bn (encrypted + 1, len, x);
-		BN_bin2bn (encrypted + 1 + len, len, y);
+		if (zeroPadding)
+		{
+			BN_bin2bn (encrypted + 1, len, x);
+			BN_bin2bn (encrypted + 1 + len, len, y);
+		}
+		else
+		{
+			BN_bin2bn (encrypted, len, x);
+			BN_bin2bn (encrypted + len, len, y);
+		}
 		auto p = EC_POINT_new (curve);
 		if (EC_POINT_set_affine_coordinates_GFp (curve, p, x, y, nullptr))
 		{
@@ -439,7 +461,10 @@ namespace crypto
 			CBCDecryption decryption;
 			decryption.SetKey (shared);
 			decryption.SetIV (iv);
-			decryption.Decrypt (encrypted + 258, 256, m);
+			if (zeroPadding)	
+				decryption.Decrypt (encrypted + 258, 256, m);
+			else
+				decryption.Decrypt (encrypted + 256, 256, m);	
 			// verify and copy
 			uint8_t hash[32];
 			SHA256 (m + 33, 222, hash);

libi2pd/Crypto.h

@@ -54,8 +54,8 @@ namespace crypto
 	void GenerateElGamalKeyPair (uint8_t * priv, uint8_t * pub);
 
 	// ECIES
-	void ECIESEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx); // 222 bytes data, 514 bytes encrypted
-	bool ECIESDecrypt (const EC_GROUP * curve, const BIGNUM * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx);
+	void ECIESEncrypt (const EC_GROUP * curve, const EC_POINT * key, const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx, bool zeroPadding = false); // 222 bytes data, 514 bytes encrypted with zeropadding, 512 without
+	bool ECIESDecrypt (const EC_GROUP * curve, const BIGNUM * key, const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx, bool zeroPadding = false);
 	void GenerateECIESKeyPair (const EC_GROUP * curve, BIGNUM *& priv, EC_POINT *& pub);
 
 	// HMAC

libi2pd/CryptoKey.cpp

@@ -47,7 +47,7 @@ namespace crypto
 	void ECIESP256Encryptor::Encrypt (const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx)
 	{
 		if (m_Curve && m_PublicKey)
-			ECIESEncrypt (m_Curve, m_PublicKey, data, encrypted, ctx);
+			ECIESEncrypt (m_Curve, m_PublicKey, data, encrypted, ctx, true);
 	}
 
 	ECIESP256Decryptor::ECIESP256Decryptor (const uint8_t * priv)
@@ -65,7 +65,7 @@ namespace crypto
 	bool ECIESP256Decryptor::Decrypt (const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx)
 	{
 		if (m_Curve && m_PrivateKey)
-			return ECIESDecrypt (m_Curve, m_PrivateKey, encrypted, data, ctx);
+			return ECIESDecrypt (m_Curve, m_PrivateKey, encrypted, data, ctx, true);
 		return false;
 	}
 
@@ -107,7 +107,7 @@ namespace crypto
 	void ECIESGOSTR3410Encryptor::Encrypt (const uint8_t * data, uint8_t * encrypted, BN_CTX * ctx)
 	{
 		if (m_PublicKey)
-			ECIESEncrypt (GetGOSTR3410Curve (eGOSTR3410CryptoProA)->GetGroup (), m_PublicKey, data, encrypted, ctx);
+			ECIESEncrypt (GetGOSTR3410Curve (eGOSTR3410CryptoProA)->GetGroup (), m_PublicKey, data, encrypted, ctx, true);
 	}
 
 	ECIESGOSTR3410Decryptor::ECIESGOSTR3410Decryptor (const uint8_t * priv)
@@ -123,7 +123,7 @@ namespace crypto
 	bool ECIESGOSTR3410Decryptor::Decrypt (const uint8_t * encrypted, uint8_t * data, BN_CTX * ctx)
 	{
 		if (m_PrivateKey)
-			return ECIESDecrypt (GetGOSTR3410Curve (eGOSTR3410CryptoProA)->GetGroup (), m_PrivateKey, encrypted, data, ctx);
+			return ECIESDecrypt (GetGOSTR3410Curve (eGOSTR3410CryptoProA)->GetGroup (), m_PrivateKey, encrypted, data, ctx, true);
 		return false;
 	}