Message Signing

Blacknet account can sign a message for the purpose of authenticated out-of-band communication.^[1]

The used digital signature scheme is Ed25519-BLAKE2b.^[2][3] The message is fed into BLAKE2b-256 hashing function with a prefix Blacknet Signed Message:\n. Verification requires an account address, a message signature, an original message. Make sure the message is nonreplayable as needed for your use case.

RPC

• Sign message
  Type	POST
  Path	/api/v2/signmessage
  Parameters
  mnemonic	mnemonic of signing account
  message	text message

  Returns signature.

• Verify message
  Type	GET
  Path	/api/v2/verifymessage/{from}/{signature}/{message}
  Parameters
  from	address of signing account
  signature	signature to verify
  message	text message

  Returns boolean.

Libraries

• Dart https://pub.dev/packages/blacknet_lib
• Go https://gitlab.com/blacknet-ninja/blacknetgo-lib
• JavaScript https://www.npmjs.com/package/blacknetjs
• PHP https://packagist.org/packages/blacknet/lib

RPC-CLI

• Python https://github.com/hclivess/blacknet_tools

References

1. khal, Sign and verify message with bitcoin address and public key, April 24, 2011.
2. Daniel Bernstein, Niels Duif, Tanja Lange, Peter Schwabe, Bo-Yin Yang, High-speed high-security signatures, September 26, 2011.
3. Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O’Hearn, Christian Winnerlein, BLAKE2: simpler, smaller, fast as MD5, January 29, 2013.