Addr Tx Sign

addr & tx & sign
    ec-to-addr            convert an EC public key to a paymant address. default is qx address.
    tx-encode             encode a unsigned transaction.
    tx-decode             decode a transaction in base16 to json format.
    tx-sign               sign a transactions using a private key.
    msg-sign              create a message signature.
    msg-verify            validate a message signature.