69 lines
1.4 KiB
Go
69 lines
1.4 KiB
Go
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package crypto
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import (
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"bytes"
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"crypto/aes"
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"crypto/cipher"
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"fmt"
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)
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func PKCS7Padding(ciphertext []byte, blockSize int) []byte {
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m := blockSize - len(ciphertext)%blockSize
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n := bytes.Repeat([]byte{byte(m)}, m)
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return append(ciphertext, n...)
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}
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func PKCS7UnPadding(origData []byte) []byte {
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m := len(origData)
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n := int(origData[m-1])
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if m > n {
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return origData[:(m - n)]
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} else {
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return origData
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}
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}
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func Encrypt(buf, key []byte) ([]byte, error) {
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var (
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err error
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blockSize int
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block cipher.Block
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)
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if block, err = aes.NewCipher(key); err != nil {
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return nil, err
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}
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defer func() {
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if v := recover(); v != nil {
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err = fmt.Errorf("decrypt error %v", v)
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}
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}()
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blockSize = block.BlockSize()
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buf = PKCS7Padding(buf, blockSize)
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blockMode := cipher.NewCBCEncrypter(block, key[:blockSize])
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tmp := make([]byte, len(buf))
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blockMode.CryptBlocks(tmp, buf)
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return tmp, nil
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}
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func Decrypt(buf, key []byte) ([]byte, error) {
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var (
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err error
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blockSize int
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block cipher.Block
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)
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if block, err = aes.NewCipher(key); err != nil {
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return nil, err
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}
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defer func() {
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if v := recover(); v != nil {
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err = fmt.Errorf("decrypt error %v", v)
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}
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}()
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blockSize = block.BlockSize()
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blockMode := cipher.NewCBCDecrypter(block, key[:blockSize])
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origData := make([]byte, len(buf))
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blockMode.CryptBlocks(origData, buf)
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origData = PKCS7UnPadding(origData)
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return origData, nil
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}
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