AES-256-GCM 解码

Question

我尝试使用java7实现AES-256-GCM解码 我在 GCM 中遇到了 mac 检查失败响应 请大家帮帮我，谢谢大家。

import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

  public static void main(String[] args) throws Exception {
    String iv = "35d117c42d1c1835420b6b9942dd4f1b"; // utf-8
    String key = "3a7bd3e2360a3d29eea436fcfb7e44c7"; // utf-8
    String hexCipherString = "07a604fc0c143a6e"; // hex
    String hexAuthTagString = "984e81176ff260717beb184db3d73753"; //hex

    byte[] decodedCipherHexBtye = Hex.decodeHex(hexCipherString.toCharArray());
    byte[] base64Cipher = Base64.decodeBase64(decodedCipherHexBtye);
    byte[] decodedAuthTagHex = Hex.decodeHex(hexAuthTagString.toCharArray());
    byte[] base64AuthTag = Base64.decodeBase64(decodedAuthTagHex);

    SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
    byte[] gcmIv = iv.getBytes("UTF-8");

    Security.addProvider(new BouncyCastleProvider());
    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding", "BC");
    GCMParameterSpec params = new GCMParameterSpec(base64AuthTag.length * Byte.SIZE, gcmIv);
    cipher.init(Cipher.DECRYPT_MODE, skeySpec, params);
    cipher.updateAAD(base64AuthTag);
    byte[] result = cipher.doFinal(base64Cipher);
    System.out.println(Base64.encodeBase64(result));
  }

期待Base64Encode的预期结果：dGVzdA==

Answer 1

如何解决安全警告注释以实现安全代码。

警告中的核心问题是每次加密都需要一个随机生成的 IV（一组真正随机的字节）

当您制作 Cypher 时，这里有一个使用 Java 8 Oracle SE 的具体示例

       val cipher = Cipher.getInstance("some scheme", "some provider");

那么当我们安全地使用 Cypher 时，我们需要一个真正的随机初始化向量 IV 来正确解决这个警告也指向我们的问题，

事实证明，至少在 Oracle Java 8 中这很容易，

使用上述密码

    cipher.getIV()

密码对象的实例方法是安全的see

一般与IvParameterSpec一起使用

    ivParams = IvParameterSpec( cipher.getIV())
    cipher.init(Cipher.ENCRYPT_MODE, key, ivParams);

Answer 2

我找到了解决办法，修改代码如下：

  public static void main(String[] args) throws Exception {
    String iv = "35d117c42d1c1835420b6b9942dd4f1b"; // utf-8
    String key = "3a7bd3e2360a3d29eea436fcfb7e44c7"; // utf-8
    String hexCipherString = "07a604fc0c143a6e"; // hex
    String hexAuthTagString = "984e81176ff260717beb184db3d73753"; //hex

    byte[] decodedCipherHexBtye = Hex.decodeHex(hexCipherString.toCharArray());
    byte[] decodedAuthTagHex = Hex.decodeHex(hexAuthTagString.toCharArray());

    SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes("UTF-8"), "AES");
    byte[] gcmIv = iv.getBytes("UTF-8");

    Security.addProvider(new BouncyCastleProvider());
    Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding", "BC");
    GCMParameterSpec params = new GCMParameterSpec(decodedAuthTagHex.length * Byte.SIZE, gcmIv);
    cipher.init(Cipher.DECRYPT_MODE, skeySpec, params);
    cipher.update(decodedCipherHexBtye);
    byte[] result = cipher.doFinal(decodedAuthTagHex);
    
    System.out.println(new String(result));
  }

参考这篇文章 Tag mismatch error in AES-256-GCM Decryption using Java

Answer 3

这是使用 AES-256 进行加密和解密的最简单方法。

if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
     String decryptedData = AESUtils.decrypt("Your Encrypted Data");
     System.out.println(decryptedData);
}

public class AESUtils {
private static final String ENCRYPTION_KEY = "RwcmlVpg";
private static final String ENCRYPTION_IV = "5183666c72eec9e4";

@RequiresApi(api = Build.VERSION_CODES.O)
public static String encrypt(String src) {
    try {
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, makeKey(), makeIv());
        byte[] origignal= Base64.encode(cipher.doFinal(src.getBytes()),Base64.DEFAULT);
        return new String(origignal);
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

@RequiresApi(api = Build.VERSION_CODES.O)
public static String decrypt(String src) {
    String decrypted = "";
    try {
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, makeKey(), makeIv());
        byte[] decode = Base64.decode(src, Base64.NO_WRAP);
        decrypted= new String(cipher.doFinal(decode), "UTF-8");
    } catch (Exception e) {
        Log.v("AES Exception", String.valueOf(e));

        throw new RuntimeException(e);
    }
    return decrypted;
}

static AlgorithmParameterSpec makeIv() {
    try {
        return new IvParameterSpec(ENCRYPTION_IV.getBytes("UTF-8"));
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }
    return null;
}

static Key makeKey() {
    try {
        MessageDigest md = MessageDigest.getInstance("SHA-256");
        byte[] key = md.digest(ENCRYPTION_KEY.getBytes("UTF-8"));
        return new SecretKeySpec(key, "AES");
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }

    return null;
}
}