安卓逆向--自吐算法(3DES和AES)

admin 2021年12月17日18:04:37评论160 views字数 2930阅读9分46秒阅读模式

一、3DES源码

String bs= "逆向有你a";DESedeKeySpec des3key = new DESedeKeySpec(("123456781234567812345678".getBytes(StandardCharsets.UTF_8)));//密钥必须是24个字节SecretKeyFactory keydes3 = SecretKeyFactory.getInstance("DESede");SecretKey secretKey3 = keydes3.generateSecret(des3key);Cipher cipher3des = Cipher.getInstance("DESede/ECB/PKCS5Padding");cipher3des.init(1,secretKey3);byte[] des3res = cipher3des.doFinal(bs.getBytes(StandardCharsets.UTF_8));System.out.println("3DES加密(字节):"+Arrays.toString(des3res));System.out.println("3DES加密(Hex):"+bytes2HexString(des3res));System.out.println("3DES加密(Base64):"+Base64.getEncoder().encodeToString(des3res));cipher3des.init(2,secretKey3);//初始化解密byte[] jm3desres = cipher3des.doFinal(Base64.getDecoder().decode("vN3o+PDQ0Yo8y5+InEzpwA==".getBytes(StandardCharsets.UTF_8)));System.out.println("3DES解密(Base64):"+new String(jm3desres));byte[] des3hexbyte =hexString2Bytes("BCDDE8F8F0D0D18A3CCB9F889C4CE9C0");jm3desres=cipher3des.doFinal(des3hexbyte);System.out.println("3DES解密(Hex):"+new String(jm3desres));


二、分析源码,需hook的内容

3DES除了key和DES有区别外,其他的iv向量和dofinal都一样,所以只要hook类javax.crypto.spec.DESedeKeySpec就可以了


三、hook源码

XposedBridge.hookAllConstructors(XposedHelpers.findClass(        "javax.crypto.spec.DESedeKeySpec",        loadPackageParam.classLoader),        new XC_MethodHook() {            /* access modifiers changed from: protected */            public void beforeHookedMethod(XC_MethodHook.MethodHookParam param) throws Throwable {                Log.e("逆向有你", "Stack:", new Throwable("stack dump"));                byte[] keybyte = new byte[24];                int offset = 0;                if (param.args.length != 1) {                    offset = ((Integer) param.args[1]).intValue();                }                System.arraycopy((byte[]) param.args[0], offset, keybyte, 0, 24);                String keyHex = b2s(keybyte);                String keyB64 = Base64.encodeToString(keybyte, 0);                Log.d("逆向有你", "3DESKey:" + new String(keybyte));                Log.d("逆向有你", "3DESKeyHex:" + keyHex);                Log.d("逆向有你", "3DESKeyB64:" + keyB64);                Log.d("逆向有你", "=====================3DESKey=========================");            }        });


四、AES算法源码

String bs= "逆向有你a";SecretKeySpec aeskey = new SecretKeySpec("1234567812345678".getBytes(StandardCharsets.UTF_8),"AES");//获取密钥的实例IvParameterSpec aesiv = new IvParameterSpec("1234567812345678".getBytes(StandardCharsets.UTF_8));//获取IV向量的实例Cipher aescp = Cipher.getInstance("AES/CBC/PKCS5Padding");//告诉系统加密模式还有填充方式aescp.init(1,aeskey,aesiv);//初始化加密方法byte[] aesres = aescp.doFinal(bs.getBytes(StandardCharsets.UTF_8));//使用dofinal加密System.out.println("aes加密(字节):"+Arrays.toString(aesres));System.out.println("aes加密(Hex):"+bytes2HexString(aesres));System.out.println("aes加密(Base64):"+Base64.getEncoder().encodeToString(aesres));aescp.init(2,aeskey,aesiv);//初始化解密byte[] jmaesres = aescp.doFinal(Base64.getDecoder().decode("MEpgbtD9muLvf6krtX86Og==".getBytes(StandardCharsets.UTF_8)));System.out.println("aes解密(Base64):"+new String(jmaesres));byte[] jmhexbyte =hexString2Bytes("304A606ED0FD9AE2EF7FA92BB57F3A3A");jmhexbyte=aescp.doFinal(jmhexbyte);System.out.println("aes解密(Hex):"+new String(jmhexbyte));


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安卓逆向--自吐算法(3DES和AES)

安卓逆向 -- 自吐算法(3DES和AES)

原文始发于微信公众号(web安全工具库):安卓逆向 -- 自吐算法(3DES和AES)

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  • 本文由 发表于 2021年12月17日18:04:37
  • 转载请保留本文链接(CN-SEC中文网:感谢原作者辛苦付出):
                   安卓逆向--自吐算法(3DES和AES)http://cn-sec.com/archives/564777.html

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