zerospad.go

// Useful for AES encryption.

// Pad the ciphertext with zeros until it is of length blockSize.
func ZerosPad(ciphertext []byte, blockSize int) []byte {
	// determine number of zeros to add
	padLen := blockSize - (len(ciphertext) % blockSize)

	padText := bytes.Repeat([]byte{0}, padLen)
	ciphertext = append(ciphertext, padText...)

	return ciphertext
}

// Trim the trailing zeros from ciphertext.
func ZerosUnpad(ciphertext []byte) []byte {
	return bytes.TrimRight(ciphertext, string(byte(0)))
}