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aes_crypt.go
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aes_crypt.go
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package secutil
import (
"crypto/aes"
"crypto/cipher"
"github.com/gookit/goutil/byteutil"
)
// aes methods
const (
CryptAes128CBC = "aes-128-cbc"
CryptAes256CBC = "aes-256-cbc"
)
// padding type for encoding contents.
const (
PadTypeNone uint8 = iota
PadTypeZeros
PadTypePKCS5
PadTypePKCS7
)
// type BlockModeFunc func(b cipher.Block, iv []byte, isEnc bool) cipher.BlockMode
// CryptConfig struct
type CryptConfig struct {
Key string
// IV string, length must be equals to cipher.Block.BlockSize()
IV string
// Method name. eg: CryptAes256CBC
Method string
// PadType for padding string.
PadType uint8
Encoder byteutil.BytesEncoder
// BlockModeFn for create encrypter or decrypter blockMode
// BlockModeFn BlockModeFunc
}
// AesCrypt struct
type AesCrypt struct {
CryptConfig
// iv length must is 16 = aes.BlockSize
iv []byte
key []byte
init bool
keyLen int
// padding string
encryptType string
}
// NewAesCrypt instance
func NewAesCrypt() *AesCrypt {
return &AesCrypt{
CryptConfig: CryptConfig{
Method: CryptAes256CBC,
PadType: PadTypePKCS5,
Encoder: byteutil.B64Encoder,
},
}
}
// Config crypt instance
func (p *AesCrypt) Config(fn func(c *CryptConfig)) *AesCrypt {
fn(&p.CryptConfig)
return p
}
// Init crypt instance
func (p *AesCrypt) Init() error {
if p.init {
return nil
}
p.init = true
switch p.Method {
case CryptAes128CBC:
p.keyLen = 16
p.encryptType = "cbc"
case CryptAes256CBC:
p.keyLen = 32
p.encryptType = "cbc"
}
// iv length must is 16 = aes.BlockSize
p.iv = []byte(p.IV)
// padding ASCII 0(NUL)
p.key = make([]byte, p.keyLen)
copy(p.key, p.Key)
return nil
}
// Encrypt input source bytes. return error on fail.
func (p *AesCrypt) Encrypt(src []byte) ([]byte, error) {
if err := p.Init(); err != nil {
return nil, err
}
// TODO 优化: 在 Init() 创建好 block 和 blockMode
block, err := aes.NewCipher(p.key)
if err != nil {
return nil, err
}
padSrc := PKCS5Padding(src, block.BlockSize())
encrypted := make([]byte, len(padSrc))
blockMode := cipher.NewCBCEncrypter(block, p.iv)
blockMode.CryptBlocks(encrypted, padSrc)
if p.Encoder == nil {
return encrypted, nil
}
return p.Encoder.Encode(encrypted), nil
}
// EncryptString to encoded string. return error on fail.
func (p *AesCrypt) EncryptString(src string) (string, error) {
bs, err := p.Encrypt([]byte(src))
return string(bs), err
}
// Decrypt an encrypt to source data
func (p *AesCrypt) Decrypt(enc []byte) ([]byte, error) {
if err := p.Init(); err != nil {
return nil, err
}
if p.Encoder != nil {
var err error
enc, err = p.Encoder.Decode(enc)
if err != nil {
return nil, err
}
}
// TODO 优化: 在 Init() 创建好 block 和 blockMode
block, err := aes.NewCipher(p.key)
if err != nil {
return nil, err
}
blockMode := cipher.NewCBCDecrypter(block, p.iv)
srcBytes := make([]byte, len(enc))
blockMode.CryptBlocks(srcBytes, enc)
return PKCS5UnPadding(srcBytes)
}
// DecryptString to source string. return error on fail.
func (p *AesCrypt) DecryptString(enc string) (string, error) {
bs, err := p.Decrypt([]byte(enc))
return string(bs), err
}