use VerifyDigest for verification

Datagram.cpp

@@ -76,11 +76,7 @@ namespace datagram
 
 		bool verified = false;
 		if (identity.GetSigningKeyType () == i2p::data::SIGNING_KEY_TYPE_DSA_SHA1)
-		{
+			verified = CryptoPP::SHA256().VerifyDigest (signature, buf + headerLen, len - headerLen);
-			uint8_t hash[32];	
-			CryptoPP::SHA256().CalculateDigest (hash, buf + headerLen, len - headerLen);
-			verified = identity.Verify (hash, 32, signature);
-		}
 		else	
 			verified = identity.Verify (buf + headerLen, len - headerLen, signature);
 				

Garlic.cpp

@@ -418,9 +418,7 @@ namespace garlic
 		buf++; // flag
 
 		// payload
-		uint8_t hash[32];
+		if (!CryptoPP::SHA256().VerifyDigest (payloadHash, buf, payloadSize)) // payload hash doesn't match
-		CryptoPP::SHA256().CalculateDigest(hash, buf, payloadSize);
-		if (memcmp (hash, payloadHash, 32)) // payload hash doesn't match
 		{
 			LogPrint ("Wrong payload hash");
 			return;

NTCPSession.cpp

@@ -255,11 +255,10 @@ namespace transport
 			
 			m_Decryption.Decrypt((uint8_t *)&m_Establisher->phase2.encrypted, sizeof(m_Establisher->phase2.encrypted), (uint8_t *)&m_Establisher->phase2.encrypted);
 			// verify
-			uint8_t xy[512], hxy[32];
+			uint8_t xy[512];
 			memcpy (xy, m_DHKeysPair->publicKey, 256);
 			memcpy (xy + 256, m_Establisher->phase2.pubKey, 256);
-			CryptoPP::SHA256().CalculateDigest(hxy, xy, 512); 
+			if (!CryptoPP::SHA256().VerifyDigest(m_Establisher->phase2.encrypted.hxy, xy, 512)) 
-			if (memcmp (hxy, m_Establisher->phase2.encrypted.hxy, 32))
 			{
 				LogPrint (eLogError, "Incorrect hash");
 				transports.ReuseDHKeysPair (m_DHKeysPair);