1 files changed, 76 insertions, 0 deletions
diff --git a/src/util/message.h b/src/util/message.h
new file mode 100644
index 0000000000..b31c5f5761
--- /dev/null
+++ b/src/util/message.h
@@ -0,0 +1,76 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_MESSAGE_H
+#define BITCOIN_UTIL_MESSAGE_H
+
+#include <key.h> // For CKey
+#include <uint256.h>
+
+#include <string>
+
+extern const std::string MESSAGE_MAGIC;
+
+/** The result of a signed message verification.
+ * Message verification takes as an input:
+ * - address (with whose private key the message is supposed to have been signed)
+ * - signature
+ * - message
+ */
+enum class MessageVerificationResult {
+    //! The provided address is invalid.
+    ERR_INVALID_ADDRESS,
+
+    //! The provided address is valid but does not refer to a public key.
+    ERR_ADDRESS_NO_KEY,
+
+    //! The provided signature couldn't be parsed (maybe invalid base64).
+    ERR_MALFORMED_SIGNATURE,
+
+    //! A public key could not be recovered from the provided signature and message.
+    ERR_PUBKEY_NOT_RECOVERED,
+
+    //! The message was not signed with the private key of the provided address.
+    ERR_NOT_SIGNED,
+
+    //! The message verification was successful.
+    OK
+};
+
+enum class SigningResult {
+    OK, //!< No error
+    PRIVATE_KEY_NOT_AVAILABLE,
+    SIGNING_FAILED,
+};
+
+/** Verify a signed message.
+ * @param[in] address Signer's bitcoin address, it must refer to a public key.
+ * @param[in] signature The signature in base64 format.
+ * @param[in] message The message that was signed.
+ * @return result code */
+MessageVerificationResult MessageVerify(
+    const std::string& address,
+    const std::string& signature,
+    const std::string& message);
+
+/** Sign a message.
+ * @param[in] privkey Private key to sign with.
+ * @param[in] message The message to sign.
+ * @param[out] signature Signature, base64 encoded, only set if true is returned.
+ * @return true if signing was successful. */
+bool MessageSign(
+    const CKey& privkey,
+    const std::string& message,
+    std::string& signature);
+
+/**
+ * Hashes a message for signing and verification in a manner that prevents
+ * inadvertently signing a transaction.
+ */
+uint256 MessageHash(const std::string& message);
+
+std::string SigningResultString(const SigningResult res);
+
+#endif // BITCOIN_UTIL_MESSAGE_H