package crypto

import "bytes"

type Crypto struct {
}

const defaultAesKey = "wVQvqtER8xzTLKB0f9Y4S_30ZF0rEDAN" //8 16 32
const defaultDesKey = "Xj9UnbYA"                         //max 8

// complement method
func pKCS7Padding(ciphertext []byte, blocksize int) []byte {
	padding := blocksize - len(ciphertext)%blocksize
	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
	return append(ciphertext, padtext...)
}

// to code method
func pKCS7UnPadding(origData []byte) []byte {
	length := len(origData)
	unpadding := int(origData[length-1])
	return origData[:(length - unpadding)]
}

// zeroPadding zero padding function
func zeroPadding(ciphertext []byte, blockSize int) []byte {
	padding := blockSize - len(ciphertext)%blockSize
	padtext := bytes.Repeat([]byte{0}, padding)
	return append(ciphertext, padtext...)
}

// zeroUnPadding zero unPadding function
func zeroUnPadding(origData []byte) []byte {
	return bytes.TrimFunc(origData,
		func(r rune) bool {
			return r == rune(0)
		})
}