Function pad

hashing/sha256/sha256.go:37–47

pad returns a padded version of the input message, such as the padded message's length is a multiple of 512 bits. The padding methodology is as follows: A "1" bit is appended at the end of the input message, followed by m "0" bits such as the length is 64 bits short of a 512 bits multiple. The remai

(message []byte)

// message, represented as a 64-bits unsigned integer.
// For more details, see: https://datatracker.ietf.org/doc/html/rfc6234#section-4.1
func pad(message []byte) []byte {
	L := make([]byte, 8)
	binary.BigEndian.PutUint64(L, uint64(len(message)*8))
	message = append(message, 0x80) // "1" bit followed by 7 "0" bits
	for (len(message)+8)%64 != 0 {
		message = append(message, 0x00) // 8 "0" bits
	}
	message = append(message, L...)

	return message
}

// Hash hashes the input message using the sha256 hashing function, and return a 32 byte array.
// The implementation follows the RGC6234 standard, which is documented