如何为Base64应用填充 [英] How to apply padding for Base64

问题描述

当我使用四个字母的单词作为输入时，我有以下代码可以正常工作，例如测试。当输入不是4的倍数时，如E.g. MyTest的。

I have following code that works fine when I use a four letter word as input, E.g. "Test". When the input is not a multiple of 4, it fails E.g. "MyTest".

Eexception：Base-64 char数组的长度无效。

Eexception: Invalid length for a Base-64 char array.

问题

1. 保证加密结果始终与Unicode字符串（没有任何损失）。如果是，我可以使用UTF编码而不是Base64？ UTF8 / UTF16与Base64在编码方面


2. 即使输入不是4的倍数，如何添加填充使得我们得到正确的结果（解密后）？

主要PRGORAM

class Program
{
    static void Main(string[] args)
    {
        string valid128BitString = "AAECAwQFBgcICQoLDA0ODw==";
        string inputValue = "MyTest";
        string keyValue = valid128BitString;


        byte[] byteValForString = Convert.FromBase64String(inputValue);
        EncryptResult result = Aes128Utility.EncryptData(byteValForString, keyValue);
        EncryptResult encyptedValue = new EncryptResult();
        string resultingIV = "4uy34C9sqOC9rbV4GD8jrA==";
        if (String.Equals(resultingIV,result.IV))
        {
            int x = 0;
        }

        encyptedValue.IV = resultingIV;
        encyptedValue.EncryptedMsg = result.EncryptedMsg;

        string finalResult = Convert.ToBase64String(Aes128Utility.DecryptData(encyptedValue, keyValue));
        Console.WriteLine(finalResult);

        if (String.Equals(inputValue, finalResult))
        {
            Console.WriteLine("Match");
        }
        else
        {
            Console.WriteLine("Differ");
        }

        Console.ReadLine();
    }
}

AES加密实用 / p>

AES Crypto UTILITY

public static class Aes128Utility
{
    private static byte[] key;

    public static EncryptResult EncryptData(byte[] rawData, string strKey)
    {
        EncryptResult result = null;
        if (key == null)
        {
            if (!String.IsNullOrEmpty(strKey))
            {
                key = Convert.FromBase64String((strKey));
                result = Encrypt(rawData);
            }
        }
        else
        {
            result = Encrypt(rawData);
        }

        return result; 

    }

    public static byte[] DecryptData(EncryptResult encryptResult, string strKey)
    {
        byte[] origData = null;
        if (key == null)
        {
            if (!String.IsNullOrEmpty(strKey))
            {
                key = Convert.FromBase64String(strKey);
                origData = Decrypt(Convert.FromBase64String(encryptResult.EncryptedMsg), Convert.FromBase64String(encryptResult.IV));
            }
        }
        else
        {
            origData = Decrypt(Convert.FromBase64String(encryptResult.EncryptedMsg), Convert.FromBase64String(encryptResult.IV));
        }

        return origData; 
    }

    private static EncryptResult Encrypt(byte[] rawData)
    {
        using (AesCryptoServiceProvider aesProvider = new AesCryptoServiceProvider())
        {
            aesProvider.Key = key;
            aesProvider.Mode = CipherMode.CBC;
            aesProvider.Padding = PaddingMode.PKCS7;
            aesProvider.IV = Convert.FromBase64String("4uy34C9sqOC9rbV4GD8jrA==");
            using (MemoryStream memStream = new MemoryStream())
            {
                CryptoStream encStream = new CryptoStream(memStream, aesProvider.CreateEncryptor(), CryptoStreamMode.Write);
                encStream.Write(rawData, 0, rawData.Length);
                encStream.FlushFinalBlock();
                EncryptResult encResult = new EncryptResult();
                encResult.EncryptedMsg = Convert.ToBase64String(memStream.ToArray());
                encResult.IV = Convert.ToBase64String(aesProvider.IV);
                return encResult;
            }
        }
    }

    private static byte[] Decrypt(byte[] encryptedMsg, byte[] iv)
    {
        using (AesCryptoServiceProvider aesProvider = new AesCryptoServiceProvider())
        {
            aesProvider.Key = key;
            aesProvider.IV = iv;
            aesProvider.Mode = CipherMode.CBC;
            aesProvider.Padding = PaddingMode.PKCS7;
            using (MemoryStream memStream = new MemoryStream())
            {
                CryptoStream decStream = new CryptoStream(memStream, aesProvider.CreateDecryptor(), CryptoStreamMode.Write);
                decStream.Write(encryptedMsg, 0, encryptedMsg.Length);
                decStream.FlushFinalBlock();
                return memStream.ToArray();
            }
        }
    }

 }

DTO

public class EncryptResult
{
    public string EncryptedMsg { get; set; }
    public string IV { get; set; }
}

参考：

1. 如何使用FromBase64String创建长度为16的byte []？


2. 使用AesCryptoServiceProvider获取不正确的解密值

1. How to create byte[] with length 16 using FromBase64String
2. Getting incorrect decryption value using AesCryptoServiceProvider

推荐答案

Base64是一种将二进制值表示为文本的方式，这样您就不会与常用的控件代码冲突，例如换行符 \x0A 或 \0 为字符串终止符。 不将键入的文本转换为二进制。

Base64 is a way of representing binary values as text so that you do not conflict with common control codes like \x0A for newline or \0 for a string terminator. It is NOT for turning typed text in to binary.

这是您应该如何传递文本并让它退出。您可以用您想要的任何编码替换 UTF8 ，但您需要确保 Encoding.Whatever.GetBytes 是与

Here is how you should be passing the text in and getting it back out. You can replace UTF8 with whatever encoding you want, but you will need to make sure the Encoding.Whatever.GetBytes is the same encoding as the Encoding.Whatever.GetString

class Program
{
    static void Main(string[] args)
    {
        string valid128BitString = "AAECAwQFBgcICQoLDA0ODw==";
        string inputValue = "MyTest";
        string keyValue = valid128BitString;

        //Turns our text in to binary data
        byte[] byteValForString = Encoding.UTF8.GetBytes(inputValue);

        EncryptResult result = Aes128Utility.EncryptData(byteValForString, keyValue);
        EncryptResult encyptedValue = new EncryptResult();

        //(Snip)

        encyptedValue.IV = resultingIV;
        encyptedValue.EncryptedMsg = result.EncryptedMsg;

        string finalResult = Encoding.UTF8.GetString(Aes128Utility.DecryptData(encyptedValue, keyValue));
        Console.WriteLine(finalResult);

        if (String.Equals(inputValue, finalResult))
        {
            Console.WriteLine("Match");
        }
        else
        {
            Console.WriteLine("Differ");
        }

        Console.ReadLine();
    }
}

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