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34 lines
785 B
Go
34 lines
785 B
Go
1 month ago
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package security
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import (
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"crypto/aes"
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"crypto/cipher"
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"errors"
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)
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func AESDecrypt(crypted []byte, key []byte) ([]byte, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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blockSize := block.BlockSize()
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if len(crypted) < blockSize {
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return nil, errors.New("ciphertext too short")
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}
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iv := key[:blockSize]
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if len(crypted)%blockSize != 0 {
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return nil, errors.New("ciphertext is not a multiple of the block size")
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}
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blockMode := cipher.NewCBCDecrypter(block, iv)
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blockMode.CryptBlocks(crypted, crypted)
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crypted = crypted[blockSize:]
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crypted = PKCS7UnPadding(crypted)
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return crypted, nil
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}
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func PKCS7UnPadding(origData []byte) []byte {
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length := len(origData)
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unpadding := int(origData[length-1])
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return origData[:(length - unpadding)]
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}
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