...this is the standard way to sign messages in bitcoin-qt. Note that the
format of a compressed signature, for messages, is quite distinct from DER
format, which is used in transactions. This commit also adds support for
recovering the public key from a signature, which is necessary for this. The
code for public key recover is taken from bitcoinjs-lib.
Signing a message with ECDSA involves using a random number, and this means
that two signatures should never be the same. This commit adds some basic tests
to Key.signSync and Message.sign to make sure this is the case. Also, a new
bitcore.Key should never have the same private key twice. This commit also adds
a basic test to make sure that is the case.
This adds a new Message class with static methods for signing and verifying a
message the same way as bitcoind. (In a nutshell, messages a prepended with
"Bitcoin Signed Message:" before being hashed and signed).
There is one important piece missing ... verifying a signature with an address,
and not a public key. I have not yet implemented this because the cryptography
interface of bitcore does not allow me to derive the public key from a
signature. This will need to be added before verifying from an address is
possible.
Ryan X. Charles