用Java实现Aes加密，用C#解密

Question

在Java代码中，我有源代码可以很好地工作，这是用于加密：

    import java.io.UnsupportedEncodingException;
    import java.security.MessageDigest;
    import java.security.NoSuchAlgorithmException;
    import java.util.Arrays;
    import java.util.Base64;
    import javax.crypto.spec.IvParameterSpec;
    
    import javax.crypto.Cipher;
    import javax.crypto.spec.SecretKeySpec;
    
    public class HelloWorld{
        private static final String hexKey = "B8EE12E123C0E300A202074A153CC0D27D739357480FFFFFFFFFFFFFFFFFFFEF";
        
         public static void main(String []args){
            System.out.println("Encryt ==== ");
            String textToEncrypt = "From=ABC&Key=FootID1234&Value=ResultValue2324";
            String encryptedText = encrypt(textToEncrypt);
            System.out.println(encryptedText);
            System.out.println("Decrypt ==== ");
            String decryptedText = decrypt(encryptedText);
            System.out.println(decryptedText);
         }
         
         public static String encrypt (String plainText) {
            String encryptedText = null;
            try {
                
                Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
                SecretKeySpec secretKey = new SecretKeySpec(hexToBytes(hexKey), "AES");
                            
                IvParameterSpec ivparameterspec = new IvParameterSpec(hexKey.getBytes(), 0, 16);
                cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivparameterspec);
                byte[] cipherText = cipher.doFinal(plainText.getBytes("UTF8"));
                
                encryptedText = bytesToHex(cipherText);
            } catch (Exception E) {
                System.out.println("Encrypt Exception : " + E.getMessage());
            }
            return encryptedText;
        }
       
        public static String decrypt(String encryptedText) {
            String decryptedText = null;
            try {
                
                Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
                SecretKeySpec secretKey = new SecretKeySpec(hexToBytes(hexKey), "AES");
                
                IvParameterSpec ivparameterspec = new IvParameterSpec(hexKey.getBytes("UTF8"), 0, 16);
                cipher.init(Cipher.DECRYPT_MODE, secretKey, ivparameterspec);
                byte[] cipherText = hexToBytes(encryptedText);
                byte[] dcrbyte = cipher.doFinal(cipherText);
                decryptedText = new String(dcrbyte, "UTF-8");
    
            } catch (Exception E) {
                 System.out.println("Encrypt Exception : " + E.getMessage());
            }
            return decryptedText;
        }
        
        private static byte[] hexToBytes(String hexStr) {
            byte[] val = new byte[hexStr.length() / 2];
            for (int i = 0; i < val.length; i++) {
                int idx = i * 2;
                int j = Integer.parseInt(hexStr.substring(idx, idx + 2), 16);
                val[i] = (byte) j;
            }
            return val;
        }
    
        private static String bytesToHex(byte[] hashInBytes) {
                char[] hexArray = "0123456789ABCDEF".toCharArray();
                char[] hexChars = new char[hashInBytes.length * 2];
                for (int i = 0; i < hashInBytes.length; i++) {
                    int v = hashInBytes[i] & 0xFF;
                    hexChars[i * 2] = hexArray[v >>> 4];
                    hexChars[i * 2 + 1] = hexArray[v & 0x0F];
                }
                return new String(hexChars);
            }
    }

在c#中，我尝试这样编写decryptAes()函数：

public static class Encryption
    {
        // use these parameters to test decryptAes()
        //string key = "B8EE12E123C0E300A202074A153CC0D27D739357480FFFFFFFFFFFFFFFFFFFEF";
        //string textToDecrypt = "756AD4D80E2CF1E289D55A23E092F012E8D5F372A343A419BC87F77B6335F04EFB41C3B56F5CDA167F90F67CD672A186";

        public static string decryptAes(string key, string textToDecrypt)
        {
            RijndaelManaged rijndaelCipher = new RijndaelManaged();
            // Assumed Mode and padding values.
            rijndaelCipher.Mode = CipherMode.CBC;
            rijndaelCipher.Padding = PaddingMode.PKCS7;
            // AssumedKeySize and BlockSize values.
            rijndaelCipher.KeySize = 0x80; //128
            rijndaelCipher.BlockSize = 0x80;

            // Convert Hex keys to byte Array.
            byte[] encryptedData = HexToBytes(textToDecrypt);
            //byte[] pwdBytes = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(key);
            byte[] pwdBytes = HexToBytes(key);

            byte[] keyBytes = new byte[0x10]; //16
            int len = pwdBytes.Length;
            if (len > keyBytes.Length)
            {
                len = keyBytes.Length;
            }
            Array.Copy(pwdBytes, keyBytes, len);
            rijndaelCipher.Key = keyBytes;
            rijndaelCipher.IV = keyBytes;

            // Decrypt data
            byte[] plainText = rijndaelCipher.CreateDecryptor()
                .TransformFinalBlock(encryptedData, 0, encryptedData.Length);

            return Encoding.UTF8.GetString(plainText);
        }

        public static byte[] HexToBytes(string str)
        {
            if (str.Length == 0 || str.Length % 2 != 0)
                return new byte[0];
            byte[] buffer = new byte[str.Length / 2];
            char c;
            for (int bx = 0, sx = 0; bx < buffer.Length; ++bx, ++sx)
            {
                // Convert first half of byte
                c = str[sx];
                buffer[bx] = (byte)((c > '9' ? (c > 'Z' ? (c - 'a' + 10) : (c - 'A' + 10)) : (c - '0')) << 4);
                // Convert second half of byte
                c = str[++sx];
                buffer[bx] |= (byte)(c > '9' ? (c > 'Z' ? (c - 'a' + 10) : (c - 'A' + 10)) : (c - '0'));
            }
            return buffer;
        }

        public static string ByteToHex(byte[] ba)
        {
            StringBuilder hex = new StringBuilder(ba.Length * 2);
            foreach (byte b in ba)
                hex.AppendFormat("{0:x2}", b);
            return hex.ToString().ToUpper();
        }
    }

但是c# decryptAes()函数并没有像我期望的那样工作。一个错误

System.Security.Cryptography.CryptographicException: 'Padding is invalid and cannot be removed.'

发生在第rijndaelCipher.Padding = PaddingMode.PKCS7;行

当我更改为rijndaelCipher.Padding = PaddingMode.None时，它不能像我预期的那样工作，c#结果与java的结果不同。

请帮助，任何建议都将不胜感激！谢谢!

Answer 1

您需要显式设置加密和解密的填充。除非您有其他理由，否则请使用PKCS#7填充。

rijndaelCipher.Padding=PaddingMode.none；