return when ciphertext empty

libdevcrypto/CryptoPP.cpp

@@ -53,6 +53,10 @@ void Secp256k1::decrypt(Secret const& _k, bytes& io_text)
 	CryptoPP::ECIES<CryptoPP::ECP>::Decryptor d;
 	initializeDLScheme(_k, d);
 	
+	// todo: test ecies w/null plaintext or ciphertext of \0
+	if (!io_text.size())
+		return;
+	
 	size_t clen = io_text.size();
 	bytes plain;
 	plain.resize(d.MaxPlaintextLength(io_text.size()));