C# 填充无效，无法删除AES PKCS7

我试图测试一个简单的类来加密和解密C#中的数据

`

`但是，我收到以下例外情况：

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

使用堆栈：

        StackTrace  "   at System.Security.Cryptography.CapiSymmetricAlgorithm.DepadBlock(Byte[] block, Int32 offset, Int32 count)\r\n   at System.Security.Cryptography.CapiSymmetricAlgorithm.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount)\r\n   at System.Security.Cryptography.CryptoStream.Read(Byte[] buffer, Int32 offset, Int32 count)\r\n   at System.IO.StreamReader.ReadBuffer()\r\n   at System.IO.StreamReader.ReadToEnd()\r\n   at InsuranceMidAm.Services.EncryptionService.Decrypt(String cipher, String key) in C:\\Visual Studio Projects\\InsuranceMidAm\\InsuranceMidAm\\Services\\EncryptionService.cs:line 72\r\n   at InsuranceMidAm.Tests.CryptTest.TestMethod() in C:\\Visual Studio Projects\\InsuranceMidAm\\InsuranceMidAm.Tests\\CryptTest.cs:line 20" string

这是正在测试的类：

namespace InsuranceMidAm.Services
{
    public class EncryptionService
    {
        // Reference: https://stackoverflow.com/questions/273452/using-aes-encryption-in-c-sharp
        public static String Encrypt(String text, String key)
        {

            byte[] value = UTF8Encoding.UTF8.GetBytes(text);
            byte[] crypt;
            byte[] iv;
            using (Aes myAes = Aes.Create())
            {

                myAes.KeySize = 256;
                myAes.Mode = CipherMode.CBC;
                myAes.Key = HexToBin(key);
                myAes.GenerateIV();
                myAes.Padding = PaddingMode.PKCS7;

                using (MemoryStream ms = new MemoryStream())
                {
                    using (CryptoStream cs = new CryptoStream(ms, myAes.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(value, 0, value.Length);
                        cs.FlushFinalBlock();
                        crypt = ms.ToArray();
                    }
                }
                iv = myAes.IV;
                myAes.Clear();
            }
            return ByteArrayToString(crypt) + ":" + ByteArrayToString(iv);

        }

        public static string Decrypt(String cipher, String key)
        {
            String outputString = "";
            byte[] ivBytes = HexToBin(getIV(cipher));
            byte[] valBytes = HexToBin(getSSN(cipher));

            using (Aes myAes = Aes.Create())
            {
                int size = valBytes.Count();

                myAes.KeySize = 256;
                myAes.Mode = CipherMode.CBC;
                myAes.Key = HexToBin(key);
                myAes.IV = ivBytes;
                myAes.Padding = PaddingMode.PKCS7;

                char[] output = new char[256];

                ICryptoTransform myDecrypter = myAes.CreateDecryptor(myAes.Key, myAes.IV);

                using (MemoryStream memory = new MemoryStream(ivBytes))
                {
                    using (CryptoStream cryptStream = new CryptoStream(memory, myDecrypter, CryptoStreamMode.Read))
                    {
                        using (StreamReader reader = new StreamReader(cryptStream))
                        {

                            outputString = reader.ReadToEnd();
                        }

                        return outputString;
                    }
                }

            }
        }

        private static byte[] HexToBin(String hexString)
        {


            int charCount = hexString.Length;
            byte[] output = new byte[charCount / 2];
            for (int i = 0; i < charCount; i += 2)
            {
                output[i / 2] = Convert.ToByte(hexString.Substring(i, 2), 16);
            }


            return output;
        }

        private static String getSSN(String cipher)
        {
            int delimiterIndex = cipher.IndexOf(":");
            String SSN = cipher.Substring(0, delimiterIndex);
            return SSN;
        }


        private static String getIV(String cipher)
        {
            int delimiterIndex = cipher.IndexOf(":");
            String IV = cipher.Substring(delimiterIndex + 1);
            return IV;
        }




        // Reference: https://stackoverflow.com/questions/311165/how-do-you-convert-a-byte-array-to-a-hexadecimal-string-and-vice-versa
        private static string ByteArrayToString(byte[] ba)
        {
            string hex = BitConverter.ToString(ba);
            return hex.Replace("-", "");
        }

    }
}

我引用了，但无法解决我的问题

最初，数据在PHP应用程序中加密，然后使用C#应用程序解密（使用几乎完全相同的解密方法）。现在，我想用C#对数据进行加密和解密；但是，我仍然必须能够正确地解密现有数据（使用PHP加密），因此我不希望对解密方法进行太多修改

---

如果您有任何建议，我们将不胜感激。

您这里有一个小错误：

ICryptoTransform myDecrypter = myAes.CreateDecryptor(myAes.Key, myAes.IV);
using (MemoryStream memory = new MemoryStream(ivBytes))

传递IV值进行解密，而不是实际加密的字节。修正：

ICryptoTransform myDecrypter = myAes.CreateDecryptor(myAes.Key, myAes.IV);
using (MemoryStream memory = new MemoryStream(valBytes))

---

多谢各位,；这就解决了问题。看起来不同的错误可能导致相同的异常；伟大的观察。：）@Kelly是的，任何在解密文本的末尾出现的错误都会导致“错误填充”异常，使用错误类型的填充也会出现这种情况。无论哪种方式，解密代码都无法识别正确的填充并抛出异常。@KellyMarchewa因为您将随机生成的值传递给decrypt（IV）-您可能会得到任何类型的错误。如果你很幸运，并且填充是正确的，你可以解密垃圾。如果你非常幸运，并且生成的IV与加密数据相同——它甚至可以被正确解密。

ICryptoTransform myDecrypter = myAes.CreateDecryptor(myAes.Key, myAes.IV);
using (MemoryStream memory = new MemoryStream(ivBytes))

ICryptoTransform myDecrypter = myAes.CreateDecryptor(myAes.Key, myAes.IV);
using (MemoryStream memory = new MemoryStream(valBytes))