DES對稱加密算法實現：Java，C#，Golang，Python

　　數據加密標准（DES，Data Encryption Standard，簡寫DES）是一種采用塊密碼加密的對稱密鑰算法，加密分組長度為64位，其中8、16、24、32、40、48、56、64 等8位是校驗位，其余56位作為秘鑰。

　　DES加密解密需要一個秘鑰，使用這個秘鑰加密的數據只能使用這個秘鑰解密，這樣，如果兩個客戶端在傳輸數據前先使用DES進行加密，那么就算傳輸密文被竊取，不知道秘鑰就沒辦法解密，這就保證了數據的安全性。

　　DES是比較的老的加密算法，現已被證實可被破解，能不用就不用吧，可使用AES加密算法代替：AES對稱加密算法實現：Java，C#，Golang，Python。

　　下面使用介紹各語言中的DES加密解密實現：

　　聲明　　

    1、加密解密過程分別使用比較多的ECB和CBC兩種方式來實現，ECB性能更快，但是安全性沒有CBC好，所以目前CBC用的比較多
    2、加密解密填充方式采用PKCS7，或者PKCS5，這兩者在這里的加密解密過程中的結果可以認為是一樣的
    3、CBC模式需要秘鑰及初始向量，而ECB模式只需要秘鑰即可，所以為了方便，下面封裝的方法或者函數將通過判斷是否存在初始向量來決定是使用CBC模式還是使用ECB模式

　　Java

　　Java中默認采用ECB模式，可以先做一個封裝：　　

　　

    import java.security.Key;
    
    import javax.crypto.Cipher;
    import javax.crypto.SecretKeyFactory;
    import javax.crypto.spec.DESKeySpec;
    import javax.crypto.spec.IvParameterSpec;
    
    public class DesUtil {
    
        /**
        * DES加密
        *
        * @param value
        *            待機加密明文
        * @param secretKey
        *            秘鑰
        * @param iv
        *            初始向量，如果未空，則將采用ECB模式，否則采用CBC模式
        *
        * @return 密文
        */
        public static String desEncrypt(String value, String secretKey, String iv)
                throws Exception {
            if (value == null || value.length() == 0)
                return "";
    
            Cipher cipher = initCipher(Cipher.ENCRYPT_MODE, secretKey, iv);
            byte[] bytes = cipher.doFinal(value.getBytes("utf-8"));
    
            // 使用hex格式數據輸出
            StringBuffer result = new StringBuffer();
            for (int i = 0; i < bytes.length; i++) {
                result.append(String.format("%02x", bytes[i]));
            }
            return result.toString();
    
        }
    
        /**
        * DES解密
        *
        * @param value
        *            密文
        * @param secretKey
        *            秘鑰
        * @param iv
        *            初始向量，如果未空，則將采用ECB模式，否則采用CBC模式
        *
        * @return 解密后的明文
        */
        public static String desDecrypt(String value, String secretKey, String iv)
                throws Exception {
            if (value == null || value.length() == 0)
                return "";
    
            // 轉換hex格式數據未byte數組
            int length = value.length();
            byte[] buffer = new byte[length / 2];
            for (int i = 0; i < buffer.length; i++) {
                buffer[i] = (byte) Integer.parseInt(
                        value.substring(i * 2, i * 2 + 2), 16);
            }
    
            Cipher cipher = initCipher(Cipher.DECRYPT_MODE, secretKey, iv);
            buffer = cipher.doFinal(buffer);
            return new String(buffer, "utf-8");
        }
    
        private static Cipher initCipher(int mode, String secretKey, String iv)
                throws Exception {
    
            try {
                // 獲取秘鑰數組
                byte[] secretBytes = secretKey.getBytes("utf-8");
                byte[] keyBytes = new byte[8];
                System.arraycopy(secretBytes, 0, keyBytes, 0,
                        Math.min(secretBytes.length, keyBytes.length));
                DESKeySpec dks = new DESKeySpec(keyBytes);
                SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
                Key key = keyFactory.generateSecret(dks);
    
                if (iv == null || iv.length() == 0) {
                    Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");// 采用ECB方式
                    cipher.init(mode, key);
                    return cipher;
                } else {
                    // 初始向量數組
                    byte[] ivBytes = iv.getBytes("utf-8");
                    byte[] ivKeyBytes = new byte[8];
                    System.arraycopy(ivBytes, 0, ivKeyBytes, 0,
                            Math.min(ivBytes.length, ivKeyBytes.length));
    
                    IvParameterSpec ivp = new IvParameterSpec(ivKeyBytes);
                    Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");// 采用CBC方式
                    cipher.init(mode, key, ivp);
                    return cipher;
                }
            } catch (Exception e) {
                e.printStackTrace();
                throw e;
            }
        }
    }

　　然后我們可以調用這個封裝好的類去進行加密解密：　　

    public static void main(String[] args) {
        String text = "上山打老虎";
        String key = "123456";// 秘鑰
        String iv = "abcdefg";// 初始向量
        try {
            String encryptText1 = DesUtil.desEncrypt(text, key, iv);
            System.out.printf("【%s】經過【DES-CBC】加密后：%s\n", text, encryptText1);

            String decryptText1 = DesUtil.desDecrypt(encryptText1, key, iv);
            System.out.printf("【%s】經過【DES-CBC】解密后：%s\n", encryptText1,
                    decryptText1);

            String encryptText2 = DesUtil.desEncrypt(text, key, null);
            System.out.printf("【%s】經過【DES-ECB】加密后：%s\n", text, encryptText2);

            String decryptText2 = DesUtil.desDecrypt(encryptText2, key, null);
            System.out.printf("【%s】經過【DES-ECB】解密后：%s\n", encryptText2,
                    decryptText2);

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

　　執行結果：

　　

 

　　C#

　　C#中默認采用CBC模式，同樣做一個封裝類：　　　　

　　

    using System;
    using System.Collections.Generic;
    using System.Security.Cryptography;
    using System.Text;
    
    namespace ConsoleApp1
    {
        public class DesHelper
        {
            #region DES
            /// <summary>
            /// 創建算法操作對象
            /// </summary>
            /// <param name="secretKey">秘鑰</param>
            /// <param name="iv">初始向量為空則采用ECB，否則采用CBC</param>
            /// <returns></returns>
            private static DESCryptoServiceProvider CreateCryptoServiceProvider(string secretKey, string iv)
            {
                DESCryptoServiceProvider des = new DESCryptoServiceProvider();
    
                //秘鑰數組
                byte[] secretBytes = Encoding.UTF8.GetBytes(secretKey);
                byte[] keyBytes = new byte[8];
                Array.Copy(secretBytes, keyBytes, Math.Min(secretBytes.Length, keyBytes.Length));
                des.Key = keyBytes;
    
                if (!string.IsNullOrEmpty(iv))
                {
                    //初始向量數組
                    byte[] array = Encoding.UTF8.GetBytes(iv);
                    byte[] ivBytes = new byte[keyBytes.Length];
                    Array.Copy(array, ivBytes, Math.Min(array.Length, ivBytes.Length));
                    des.IV = ivBytes;
    
                    des.Mode = CipherMode.CBC;//CBC模式
                }
                else
                {
                    des.Mode = CipherMode.ECB;//ECB模式
                }
    
                des.Padding = PaddingMode.PKCS7;//填充方式
                return des;
            }
            /// <summary> 
            /// Des加密 
            /// </summary> 
            /// <param name="value">待加密的明文</param> 
            /// <param name="secretKey">秘鑰</param>
            /// <param name="iv">初始向量為空則采用ECB，否則采用CBC</param>
            /// <returns>密文</returns> 
            public static string DesEncrypt(string value, string secretKey, string iv)
            {
                if (string.IsNullOrEmpty(value)) return string.Empty;
    
                using (DESCryptoServiceProvider des = CreateCryptoServiceProvider(secretKey, iv))
                {
                    byte[] buffer = Encoding.UTF8.GetBytes(value);
                    System.IO.MemoryStream ms = new System.IO.MemoryStream();
                    using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(buffer, 0, buffer.Length);
                        cs.FlushFinalBlock();
                        buffer = ms.ToArray();
    
                        //使用hex格式數據輸出
                        StringBuilder result = new StringBuilder();
                        foreach (byte b in buffer)
                        {
                            result.AppendFormat("{0:x2}", b);
                        }
                        return result.ToString();
                        //或者使用下面的輸出
                        //return BitConverter.ToString(buffer).Replace("-", "").ToLower();
                    }
                }
            }
            /// <summary> 
            /// Des解密 
            /// </summary> 
            /// <param name="value">密文</param> 
            /// <param name="secretKey">秘鑰</param>
            /// <param name="iv">初始向量為空則采用ECB，否則采用CBC</param>
            /// <returns>解密后的明文</returns> 
            public static string DesDecrypt(string value, string secretKey, string iv)
            {
                if (string.IsNullOrEmpty(value)) return string.Empty;
    
                using (DESCryptoServiceProvider des = CreateCryptoServiceProvider(secretKey, iv))
                {
                    //轉換hex格式數據為byte數組
                    byte[] buffer = new byte[value.Length / 2];
                    for (var i = 0; i < buffer.Length; i++)
                    {
                        buffer[i] = (byte)Convert.ToInt32(value.Substring(i * 2, 2), 16);
                    }
                    System.IO.MemoryStream ms = new System.IO.MemoryStream();
                    using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(buffer, 0, buffer.Length);
                        cs.FlushFinalBlock();
                        return Encoding.UTF8.GetString(ms.ToArray());
                    }
                }
            }
            #endregion
        }
    }

　　然后測試加密解密：

    static void Main(string[] args)
    {
        string text = "上山打老虎";
        string key = "123456"; // 秘鑰
        string iv = "abcdefg"; // 初始向量

        string encryptText1 = DesHelper.DesEncrypt(text, key, iv);
        Console.WriteLine($"【{text}】經過【DES-CBC】加密后：{encryptText1}");

        string decryptText1 = DesHelper.DesDecrypt(encryptText1, key, iv);
        Console.WriteLine($"【{encryptText1}】經過【DES-CBC】解密后：{decryptText1}");

        string encryptText2 = DesHelper.DesEncrypt(text, key, null);
        Console.WriteLine($"【{text}】經過【DES-ECB】加密后：{encryptText2}");

        string decryptText2 = DesHelper.DesDecrypt(encryptText2, key, null);
        Console.WriteLine($"【{encryptText2}】經過【DES-ECB】解密后：{decryptText2}");
    }

　　執行結果：

　　

 

　　Golang

　　可能因為ECB模式不太安全，所有go中並沒有封裝好ECB模式的直接加密解密過程，但是我們還是可以實現：　　　　

　　

package main

import (
    "bytes"
    "crypto/cipher"
    "crypto/des"
    "fmt"
    "strconv"
)

//DES加密
//iv為空則采用ECB模式，否則采用CBC模式
func DesEncrypt(value, secretKey, iv string) (string, error) {
    if value == "" {
        return "", nil
    }

    //根據秘鑰生成8位的秘鑰切片
    keyBytes := make([]byte, des.BlockSize)
    copy(keyBytes, []byte(secretKey))
    //獲取block
    block, err := des.NewCipher(keyBytes)
    if err != nil {
        return "", err
    }

    blocksize := block.BlockSize()
    valueBytes := []byte(value)

    //填充
    fillsize := blocksize - len(valueBytes)%blocksize
    repeat := bytes.Repeat([]byte{byte(fillsize)}, fillsize)
    valueBytes = append(valueBytes, repeat...)

    result := make([]byte, len(valueBytes))

    //加密
    if iv == "" {
        temp := result
        for len(valueBytes) > 0 {
            block.Encrypt(temp, valueBytes[:blocksize])
            valueBytes = valueBytes[blocksize:]
            temp = temp[blocksize:]
        }
    } else {
        //向量切片
        ivBytes := make([]byte, des.BlockSize)
        copy(ivBytes, []byte(iv))

        encrypter := cipher.NewCBCEncrypter(block, ivBytes)
        encrypter.CryptBlocks(result, valueBytes)
    }

    //以hex格式數值輸出
    encryptText := fmt.Sprintf("%x", result)
    return encryptText, nil
}

//DES解密
//iv為空則采用ECB模式，否則采用CBC模式
func DesDecrypt(value, secretKey, iv string) (string, error) {
    if value == "" {
        return "", nil
    }

    //根據秘鑰生成8位的秘鑰切片
    keyBytes := make([]byte, des.BlockSize)
    copy(keyBytes, []byte(secretKey))
    //獲取block
    block, err := des.NewCipher(keyBytes)
    if err != nil {
        return "", err
    }

    //將hex格式數據轉換為byte切片
    valueBytes := []byte(value)
    var encryptedData = make([]byte, len(valueBytes)/2)
    for i := 0; i < len(encryptedData); i++ {
        b, err := strconv.ParseInt(value[i*2:i*2+2], 16, 10)
        if err != nil {
            return "", err
        }
        encryptedData[i] = byte(b)
    }

    result := make([]byte, len(encryptedData))

    if iv == "" {
        blocksize := block.BlockSize()
        temp := result
        for len(encryptedData) > 0 {
            block.Decrypt(temp, encryptedData[:blocksize])
            encryptedData = encryptedData[blocksize:]
            temp = temp[blocksize:]
        }
    } else {
        //向量切片
        ivBytes := make([]byte, des.BlockSize)
        copy(ivBytes, []byte(iv))

        //解密
        blockMode := cipher.NewCBCDecrypter(block, ivBytes)
        blockMode.CryptBlocks(result, encryptedData)
    }

    //取消填充
    unpadding := int(result[len(result)-1])
    result = result[:(len(result) - unpadding)]
    return string(result), nil
}

　　調用測試：　　

package main

import (
    "fmt"
    "testing"
)

func TestDes(t *testing.T)  {
    text := "上山打老虎"
    key := "123456" // 秘鑰
    iv := "abcdefg" // 初始向量

    encryptText1, _ := DesEncrypt(text, key, iv)
    fmt.Printf("【%s】經過【DES-CBC】加密后：%s\n", text, encryptText1)

    decryptText1, _ := DesDecrypt(encryptText1, key, iv)
    fmt.Printf("【%s】經過【DES-CBC】解密后：%s\n", encryptText1, decryptText1)

    encryptText2, _ := DesEncrypt(text, key, "")
    fmt.Printf("【%s】經過【DES-ECB】加密后：%s\n", text, encryptText2)

    decryptText2, _ := DesDecrypt(encryptText2, key, "")
    fmt.Printf("【%s】經過【DES-ECB】解密后：%s\n", encryptText2, decryptText2)
}

　　執行結果：

　　

 

　　Python

　　python一般需要安裝pyDes包來實現DES加密解密，可以使用pip來安裝：　　

    pip install pyDes

　　默認也是采用ECB模式，所以要多注意，python相對簡單，封裝測試就放一起了：　　

# 需要安裝pyDes包：pip install pyDes
from pyDes import des, PAD_PKCS5, CBC, ECB

BLOCK_SIZE = 8


def init_cipher(secret_key, iv_key):
    secret_bytes = secret_key.encode(encoding="utf-8")
    key_bytes = []
    if len(secret_bytes) >= BLOCK_SIZE:
        key_bytes = secret_bytes[:BLOCK_SIZE]
    else:
        key_bytes.extend(secret_bytes)
        key_bytes.extend([0 for x in range(0, BLOCK_SIZE - len(secret_bytes))])

    if iv_key is None or len(iv_key) == 0:
        cipher = des(key_bytes, ECB, None, padmode=PAD_PKCS5)
        return cipher
    else:
        iv_bytes = iv_key.encode(encoding="utf-8")
        iv_key_bytes = []
        if len(iv_bytes) >= BLOCK_SIZE:
            iv_key_bytes = iv_bytes[:BLOCK_SIZE]
        else:
            iv_key_bytes.extend(iv_bytes)
            iv_key_bytes.extend([0 for x in range(0, BLOCK_SIZE - len(iv_bytes))])

        cipher = des(key_bytes, CBC, iv_key_bytes, padmode=PAD_PKCS5)
        return cipher


def des_encrypt(value, secret_key, iv_key):
    cipher = init_cipher(secret_key, iv_key)
    buffer = value.encode(encoding="utf-8")
    buffer = cipher.encrypt(buffer)
    return buffer.hex()  # 使用hex格式輸出


def des_decrypt(value, secret_key, iv_key):
    cipher = init_cipher(secret_key, iv_key)
    buffer = bytes.fromhex(value)  # 讀取hex格式數據
    buffer = cipher.decrypt(buffer)
    return buffer.decode("utf-8")


text = "上山打老虎"
key = "123456" # 秘鑰
iv = "abcdefg" # 初始向量

encryptText1 = des_encrypt(text, key, iv)
print("【", text, "】經過【DES-CBC】加密后：", encryptText1)

decryptText1 = des_decrypt(encryptText1, key, iv)
print("【", encryptText1, "】經過【DES-CBC】解密后：", decryptText1)

encryptText2 = des_encrypt(text, key, None)
print("【", text, "】經過【DES-ECB】加密后：", encryptText2)

decryptText2 = des_decrypt(encryptText2, key, None)
print("【", encryptText2, "】經過【DES-ECB】解密后：", decryptText2)

　　執行結果：