forked from chanyipiaomiao/hltool
/
aes.go
134 lines (122 loc) · 3.17 KB
/
aes.go
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package hltool
import (
"bytes"
"crypto/aes"
"crypto/cipher"
"errors"
)
func pKCS7Padding(ciphertext []byte, blockSize int) []byte {
padding := blockSize - len(ciphertext)%blockSize
padtext := bytes.Repeat([]byte{byte(padding)}, padding)
return append(ciphertext, padtext...)
}
func pKCS7UnPadding(origData []byte) []byte {
length := len(origData)
unpadding := int(origData[length-1])
return origData[:(length - unpadding)]
}
// GoAES 加密
type GoAES struct {
opt *AesOption
Key []byte
}
type AesOption struct {
Mode string // ecb, cbc
}
// NewGoAES 返回GoAES
func NewGoAES(key []byte) *GoAES {
return &GoAES{Key: key}
}
// NewGoAES 返回GoAES
func NewAES(key []byte, opt *AesOption) *GoAES {
a := &GoAES{Key: key}
if opt == nil {
a.opt = &AesOption{Mode: "cbc"}
} else {
a.opt = opt
}
return a
}
// Encrypt 加密数据
func (a *GoAES) Encrypt(origData []byte) ([]byte, error) {
block, err := aes.NewCipher(a.Key)
if err != nil {
return nil, err
}
blockSize := block.BlockSize()
origData = pKCS7Padding(origData, blockSize)
blockMode := cipher.NewCBCEncrypter(block, a.Key[:blockSize])
crypted := make([]byte, len(origData))
blockMode.CryptBlocks(crypted, origData)
return crypted, nil
}
func (a *GoAES) EncryptV2(origData []byte) ([]byte, error) {
switch a.opt.Mode {
case "ecb":
block, err := aes.NewCipher(a.Key)
if err != nil {
return nil, err
}
blockSize := block.BlockSize()
origData = pKCS7Padding(origData, blockSize)
crypted := make([]byte, len(origData))
if len(origData)%blockSize != 0 {
return nil, errors.New("crypto/cipher: input not full blocks")
}
if len(crypted) < len(origData) {
return nil, errors.New("crypto/cipher: output smaller than input")
}
// 拷贝 slice 结构,底层数组空间不变
dst, src := crypted, origData
for len(src) > 0 {
block.Encrypt(dst, src[:blockSize])
src = src[blockSize:]
dst = dst[blockSize:]
}
return crypted, nil
case "cbc":
return a.Encrypt(origData)
}
return nil, errors.New("unsupported mode")
}
// Decrypt 解密数据
func (a *GoAES) Decrypt(crypted []byte) ([]byte, error) {
block, err := aes.NewCipher(a.Key)
if err != nil {
return nil, err
}
blockSize := block.BlockSize()
blockMode := cipher.NewCBCDecrypter(block, a.Key[:blockSize])
origData := make([]byte, len(crypted))
blockMode.CryptBlocks(origData, crypted)
origData = pKCS7UnPadding(origData)
return origData, nil
}
func (a *GoAES) DecryptV2(crypted []byte) ([]byte, error) {
switch a.opt.Mode {
case "ecb":
origData := make([]byte, len(crypted))
block, err := aes.NewCipher(a.Key)
if err != nil {
return nil, err
}
blockSize := block.BlockSize()
if len(crypted)%blockSize != 0 {
return nil, errors.New("crypto/cipher: input not full blocks")
}
if len(origData) < len(crypted) {
return nil, errors.New("crypto/cipher: output smaller than input")
}
// 拷贝 slice 结构,底层数组空间不变
src, dst := crypted, origData
for len(src) > 0 {
block.Decrypt(dst, src[:blockSize])
src = src[blockSize:]
dst = dst[blockSize:]
}
return pKCS7UnPadding(origData), nil
case "cbc":
return a.Decrypt(crypted)
}
return nil, errors.New("unsupported mode")
}