AES对称加密算法实现：Java，C#，Golang，Python

　　高级加密标准（Advanced Encryption Standard，简写AES），是一种用来替代DES的对称加密算法，相比DES，AES安全性更高，加密速度更快，因此被广泛使用。

　　理论上看，AES可被破解，但是就目前的硬件性能来看，目前AES还是安全的，在开发工程中，如果要使用对称加密算法，应该首选AES。

　　下面使用介绍各语言中的DES加密解密实现：

　　声明　　

    1、加密解密过程分别使用比较多的ECB和CBC两种方式来实现，ECB性能更快，但是安全性没有CBC好，所以目前CBC用的比较多
    2、加密解密填充方式采用PKCS7，或者PKCS5，这两者在这里的加密解密过程中的结果可以认为是一样的
    3、CBC模式需要秘钥及初始向量，而ECB模式只需要秘钥即可，所以为了方便，下面封装的方法或者函数将通过判断是否存在初始向量来决定是使用CBC模式还是使用ECB模式

　　Java

　　首先，做一个封装：　　

　　

    import java.security.Key;
    
    import javax.crypto.Cipher;
    import javax.crypto.spec.IvParameterSpec;
    import javax.crypto.spec.SecretKeySpec;
    
    public class AesUtil {
    
        /**
        * DES加密
        *
        * @param value
        *            待机加密明文
        * @param secretKey
        *            秘钥
        * @param iv
        *            初始向量，如果未空，则将采用ECB模式，否则采用CBC模式
        *
        * @return 密文
        */
        public static String aesEncrypt(String value, String secretKey, String iv)
                throws Exception {
            if (value == null || value.length() == 0)
                return "";
    
            Cipher cipher = initCipher(Cipher.ENCRYPT_MODE, secretKey, iv);
            byte[] buffer = cipher.doFinal(value.getBytes("utf-8"));
            // 使用hex格式数据输出
            StringBuffer result = new StringBuffer();
            for (int i = 0; i < buffer.length; i++) {
                result.append(String.format("%02x", buffer[i]));
            }
            return result.toString();
    
        }
    
        /**
        * DES解密
        *
        * @param value
        *            密文
        * @param secretKey
        *            秘钥
        * @param iv
        *            初始向量，如果未空，则将采用ECB模式，否则采用CBC模式
        *
        * @return 解密后的明文
        */
        public static String aesDecrypt(String value, String secretKey, String iv)
                throws Exception {
            if (value == null || value.length() == 0)
                return "";
    
            // 转换hex格式数据未byte数组
            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 {
                // 获取秘钥数组
                byte[] secretBytes = secretKey.getBytes("utf-8");
                byte[] keyBytes = new byte[16];
                System.arraycopy(secretBytes, 0, keyBytes, 0,
                        Math.min(secretBytes.length, keyBytes.length));
                Key key = new SecretKeySpec(keyBytes, "AES");
    
                if (iv == null || iv.length() == 0) {
                    Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");// 采用ECB方式
                    cipher.init(mode, key);
                    return cipher;
                } else {
                    // 初始向量数组
                    byte[] ivBytes = iv.getBytes("utf-8");
                    byte[] ivKeyBytes = new byte[16];
                    System.arraycopy(ivBytes, 0, ivKeyBytes, 0,
                            Math.min(ivBytes.length, ivKeyBytes.length));
    
                    IvParameterSpec ivp = new IvParameterSpec(ivKeyBytes);
                    Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");// 采用CBC方式
                    cipher.init(mode, key, ivp);
                    return cipher;
                }
            } catch (Exception e) {
                e.printStackTrace();
                throw e;
            }
        }
    }

　　然后测试调用：　　

    public static void main(String[] args) {
        String text = "上山打老虎";
        String key = "123456";
        String iv = "abcdefg";
        try {
            String encryptText1 = AesUtil.aesEncrypt(text, key, iv);
            System.out.printf("【%s】经过【AES-CBC】加密后：%s
", text, encryptText1);

            String decryptText1 = AesUtil.aesDecrypt(encryptText1, key, iv);
            System.out.printf("【%s】经过【AES-CBC】解密后：%s
", encryptText1,
                    decryptText1);

            String encryptText2 = AesUtil.aesEncrypt(text, key, null);
            System.out.printf("【%s】经过【AES-ECB】加密后：%s
", text, encryptText2);

            String decryptText2 = AesUtil.aesDecrypt(encryptText2, key, null);
            System.out.printf("【%s】经过【AES-ECB】解密后：%s
", encryptText2,
                    decryptText2);

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

　　执行结果：

　　

　　C#

　　同样先做一个封装类：　　

　　

    using System;
    using System.Collections.Generic;
    using System.Security.Cryptography;
    using System.Text;
    
    namespace ConsoleApp1
    {
        public class AesHelper
        {
            #region AES
            /// <summary>
            /// 创建算法操作对象
            /// </summary>
            /// <param name="secretKey"></param>
            /// <param name="iv"></param>
            /// <returns></returns>
            private static RijndaelManaged CreateRijndaelManaged(string secretKey, string iv)
            {
                RijndaelManaged rijndaelManaged = new RijndaelManaged();
                rijndaelManaged.Padding = PaddingMode.PKCS7;
                rijndaelManaged.KeySize = 128;
                rijndaelManaged.BlockSize = 128;
    
                rijndaelManaged.Mode = CipherMode.CBC;
    
                byte[] secretBytes = Encoding.UTF8.GetBytes(secretKey);
                byte[] keyBytes = new byte[16];
                Array.Copy(secretBytes, keyBytes, Math.Min(secretBytes.Length, keyBytes.Length));
                rijndaelManaged.Key = keyBytes;
    
                if (string.IsNullOrEmpty(iv))
                {
                    rijndaelManaged.Mode = CipherMode.ECB;
                }
                else
                {
                    rijndaelManaged.Mode = CipherMode.CBC;
    
                    byte[] array = Encoding.UTF8.GetBytes(iv);
                    byte[] ivBytes = new byte[keyBytes.Length];
                    Array.Copy(array, ivBytes, Math.Min(array.Length, ivBytes.Length));
                    rijndaelManaged.IV = ivBytes;
                }
                return rijndaelManaged;
            }
            /// <summary>
            /// Aes加密
            /// </summary>
            /// <param name="value"></param>
            /// <param name="secretKey"></param>
            /// <param name="iv"></param>
            /// <returns></returns>
            public static string AesEncrypt(string value, string secretKey, string iv)
            {
                if (string.IsNullOrEmpty(value)) return string.Empty;
    
                using (RijndaelManaged rijndaelManaged = CreateRijndaelManaged(secretKey, iv))
                {
                    using (ICryptoTransform iCryptoTransform = rijndaelManaged.CreateEncryptor())
                    {
                        byte[] buffer = Encoding.UTF8.GetBytes(value);
                        buffer = iCryptoTransform.TransformFinalBlock(buffer, 0, buffer.Length);
                        //使用hex格式输出数据
                        StringBuilder result = new StringBuilder();
                        foreach (byte b in buffer)
                        {
                            result.AppendFormat("{0:x2}", b);
                        }
                        return result.ToString();
                        //或者使用下面的输出
                        //return BitConverter.ToString(buffer).Replace("-", "").ToLower();
                    }
                }
            }
            /// <summary>
            /// Aes解密
            /// </summary>
            /// <param name="value"></param>
            /// <param name="secretKey"></param>
            /// <param name="iv"></param>
            /// <returns></returns>
            public static string AesDecrypt(string value, string secretKey, string iv)
            {
                if (string.IsNullOrEmpty(value)) return string.Empty;
    
                using (RijndaelManaged rijndaelManaged = CreateRijndaelManaged(secretKey, iv))
                {
                    using (ICryptoTransform iCryptoTransform = rijndaelManaged.CreateDecryptor())
                    {
                        //转换hex格式数据为byte数组
                        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);
                        }
                        buffer = iCryptoTransform.TransformFinalBlock(buffer, 0, buffer.Length);
                        return Encoding.UTF8.GetString(buffer);
                    }
                }
            }
            #endregion
        }
    }

　　测试代码：　　

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

        string encryptText1 = AesHelper.AesEncrypt(text, key, iv);
        Console.WriteLine($"【{text}】经过【AES-CBC】加密后：{encryptText1}");

        string decryptText1 = AesHelper.AesDecrypt(encryptText1, key, iv);
        Console.WriteLine($"【{encryptText1}】经过【AES-CBC】解密后：{decryptText1}");

        string encryptText2 = AesHelper.AesEncrypt(text, key, null);
        Console.WriteLine($"【{text}】经过【AES-ECB】加密后：{encryptText2}");

        string decryptText2 = AesHelper.AesDecrypt(encryptText2, key, null);
        Console.WriteLine($"【{encryptText2}】经过【AES-ECB】解密后：{decryptText2}");
    }

　　执行结果：

　　

　　Golang

　　加密解密函数如下：

　　

package main

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

//AES加密
//iv为空则采用ECB模式，否则采用CBC模式
func AesEncrypt(value, secretKey, iv string) (string, error) {
    if value == "" {
        return "", nil
    }

    //根据秘钥生成16位的秘钥切片
    keyBytes := make([]byte, aes.BlockSize)
    copy(keyBytes, []byte(secretKey))
    //获取block
    block, err := aes.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, aes.BlockSize)
        copy(ivBytes, []byte(iv))

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

    //以hex格式数值输出
    encryptText := fmt.Sprintf("%x", result)
    return encryptText, nil
}

//AES解密
//iv为空则采用ECB模式，否则采用CBC模式
func AesDecrypt(value, secretKey, iv string) (string, error) {
    if value == "" {
        return "", nil
    }

    //根据秘钥生成8位的秘钥切片
    keyBytes := make([]byte, aes.BlockSize)
    copy(keyBytes, []byte(secretKey))
    //获取block
    block, err := aes.NewCipher(keyBytes)
    if err != nil {
        return "", err
    }

    //将hex格式数据转换为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, aes.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
}

　　单元测试：　　

package main

import (
    "fmt"
    "testing"
)

func TestAes(t *testing.T)  {
    text := "上山打老虎"
    key := "123456"
    iv := "abcdefg"

    encryptText1, _ := AesEncrypt(text, key, iv)
    fmt.Printf("【%s】经过【AES-CBC】加密后：%s
", text, encryptText1)

    decryptText1, _ := AesDecrypt(encryptText1, key, iv)
    fmt.Printf("【%s】经过【AES-CBC】解密后：%s
", encryptText1, decryptText1)

    encryptText2, _ := AesEncrypt(text, key, "")
    fmt.Printf("【%s】经过【AES-ECB】加密后：%s
", text, encryptText2)

    decryptText2, _ := AesDecrypt(encryptText2, key, "")
    fmt.Printf("【%s】经过【AES-ECB】解密后：%s
", encryptText2, decryptText2)
}

　　测试结果：

　　

　　Python

　　python的AES加密相对简单，同样的，需要安装pycrypto，可以使用pip安装：pip install pycryptodome（如果安装不了，先卸载旧版本再安装：pip uninstall pycrypto）。

　　直接上代码：　　

# 需要安装pycrypto，可以使用pip安装：pip install pycryptodome
from Crypto.Cipher import AES

BLOCK_SIZE = 16


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 = AES.new(bytes(key_bytes), AES.MODE_ECB)
        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 = AES.new(bytes(key_bytes), AES.MODE_CBC, bytes(iv_key_bytes))
        return cipher


def aes_encrypt(value, secret_key, iv_key):
    cipher = init_cipher(secret_key, iv_key)

    buffer = value.encode(encoding="utf-8")
    bufferList = list(buffer)

    # 数据进行 PKCS5Padding 的填充
    padding = BLOCK_SIZE - len(bufferList) % BLOCK_SIZE
    bufferList.extend([padding for x in range(0, padding)])

    buffer = cipher.encrypt(bytes(bufferList))
    return buffer.hex()  # 使用hex格式输出


def aes_decrypt(value, secret_key, iv_key):
    cipher = init_cipher(secret_key, iv_key)
    buffer = bytes.fromhex(value)  # 读取hex格式数据
    buffer = cipher.decrypt(buffer)
    result = buffer.decode("utf-8")

    # 去掉 PKCS5Padding 的填充
    return result[:-ord(result[len(result) - 1:])]


text = "上山打老虎"
key = "123456"
iv = "abcdefg"

encryptText1 = aes_encrypt(text, key, iv)
print("【", text, "】经过【AES-CBC】加密后：", encryptText1)

decryptText1 = aes_decrypt(encryptText1, key, iv)
print("【", encryptText1, "】经过【AES-CBC】解密后：", decryptText1)

encryptText2 = aes_encrypt(text, key, None)
print("【", text, "】经过【AES-ECB】加密后：", encryptText2)

decryptText2 = aes_decrypt(encryptText2, key, None)
print("【", encryptText2, "】经过【AES-ECB】解密后：", decryptText2)

　　执行结果：