Method sign_digits

bitvm/src/signatures/winternitz.rs:150–162

Creates a Winternitz signature for the given `secret_key` and `digits`. ## Output format - `hash(digits[0])` - `digits[0]` - `hash(digits[1])` - `digits[1]` - ... - `hash(digits[n + m - 1])` - `digits[n + m - 1]` There are `n` message digits followed by `m` checksum digits. The checksum is computed internally.

(ps: &Parameters, secret_key: &SecretKey, message_digits: Vec<u32>)

    /// There are `n` message digits followed by `m` checksum digits.
    /// The checksum is computed internally.
    fn sign_digits(ps: &Parameters, secret_key: &SecretKey, message_digits: Vec<u32>) -> Witness {
        let digits = add_message_checksum(ps, message_digits);
        let mut result = Witness::new();
        for i in 0..ps.total_digit_len() {
            let sig = digit_signature(secret_key, i, digits[i as usize]);
            // FIXME: Do trailing zeroes violate Bitcoin Script's minimum data push requirement?
            //        Maybe the script! macro removes the zeroes.
            //        There is a 1/256 chance that a signature contains a trailing zero.
            result.push(sig);
            result.push(bitcoin_representation(digits[i as usize] as i32));
        }
        result
    }

    /// Returns a Bitcoin script that verifies a Winternitz signature for the given `public_key`.
    ///