非对称加密算法-EW帮帮网

典型算法：RSA

需要生成一个密钥对，包含公钥和私钥，密钥不是随便写的

密钥对生成 http://web.chacuo.net/netrsakeypair

公钥加密的数据，私钥才能解密

私钥加密的数据，公钥才能解密
一般公钥是公开的，私钥保密，私钥包含公钥，从公钥无法推导出私钥
加密处理安全，但是性能极差，单次加密长度有限制
RSA算法既可用于加密解密，也可用于数据签名

RSA_Base64

私钥的格式

pkcs1格式通常开头是 -----BEGIN RSA PRIVATE KEY-----

pkcs8格式通常开头是 -----BEGIN PRIVATE KEY-----

Java中的私钥必须是pkcs8格式

RSA密钥的解析

//公钥
byte[] keyBytes = Base64Decoder.decodeBuffer(key);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(keySpec);
//私钥
byte[] keyBytes = Base64Decoder.decodeBuffer(key);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(keySpec);

RSA加解密

Cipher cipher = Cipher.getInstance("RSA/None/NOPadding");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] bt_encrypted = cipher.doFinal(bt_plaintext);

Cipher cipher = Cipher.getInstance("RSA/None/NOPadding");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] bt_original = cipher.doFinal(bt_encrypted);

RSA模式和填充细节

a) None模式与ECB模式是一致的

b) NOPadding

明文最多字节数为密钥字节数

填充字节0, 加密后的密文不变

密文与密钥等长

c) PKCS1Padding

明文最大字节数为密钥字节数-11

每一次的填充不一样，使得加密后的密文会变

密文与密钥等长

把PKCS1Padding加密后的密文，用NOPadding去解密，会怎么样呢?

没有指明加密模式和填充方式，表示使用默认的RSA/ECB/NOPadding

加密后的字节数组可以编码成Hex、Base64

RSA密钥的转换

https://www.cnblogs.com/wyzhou/p/9738964.html

openssl rsa -pubin -in public.pem -text //以文本格式输出公钥内容

openssl rsa -in private.pem -text //以文本格式输出私钥内容

a) 从PEM格式密钥中提取modulus、publicExponent、privateExponent

b) modulus、publicExponent、privateExponent转PEM格式

c) 还有极少数的modulus、publicExponent、privateExponent用十进制表示

RSA密钥的解析

先解码变成16进制数

根据最后一个00和0203 分开数据

B260571…为stringN

010001为stringE

BigInteger N = new BigInteger(stringN, 16); //16改10就可以把十进制转成大数
BigInteger E = new BigInteger(stringE, 16); 
RSAPublicKeySpec spec = new RSAPublicKeySpec(N, E);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(spec);

RSA_Hex加解密的方式与RSA_Base64一致
多种加密算法的常见结合套路

随机生成AES密钥AESKey

AESKey密钥用于AES加密数据，得到数据密文cipherText

使用RSA对AESKey加密，得到密钥密文cipherKey

提交密钥密文cipherKey和数据密文cipherText给服务器

RSA算法通杀hook

Java.perform(function () {

    function showStacks() {
        console.log(
            Java.use("android.util.Log")
                .getStackTraceString(
                    Java.use("java.lang.Throwable").$new()
                )
        );
    }

    var ByteString = Java.use("com.android.okhttp.okio.ByteString");
    function toBase64(tag, data) {
        console.log(tag + " Base64: " + ByteString.of(data).base64());
    }
    function toHex(tag, data) {
        console.log(tag + " Hex: " + ByteString.of(data).hex());
    }
    function toUtf8(tag, data) {
        console.log(tag + " Utf8: " + ByteString.of(data).utf8());
    }

    // toUtf8("xiaojianbang",[48, 49, 50, 51, 52]);
    // toBase64("xiaojianbang",[48, 49, 50, 51, 52]);
    // toHex("xiaojianbang",[48, 49, 50, 51, 52]);

    var messageDigest = Java.use("java.security.MessageDigest");
    messageDigest.update.overload('byte').implementation = function (data) {
        console.log("MessageDigest.update('byte') is called!");
        console.log("=======================================================");
        return this.update(data);
    }
    messageDigest.update.overload('java.nio.ByteBuffer').implementation = function (data) {
        console.log("MessageDigest.update('java.nio.ByteBuffer') is called!");
        console.log("=======================================================");
        return this.update(data);
    }
    messageDigest.update.overload('[B').implementation = function (data) {
        console.log("MessageDigest.update('[B') is called!");
        showStacks();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " update data";
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        console.log("=======================================================");
        return this.update(data);
    }
    messageDigest.update.overload('[B', 'int', 'int').implementation = function (data, start, length) {
        console.log("MessageDigest.update('[B', 'int', 'int') is called!");
        showStacks();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " update data";
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        console.log("=======================================================", start, length);
        return this.update(data, start, length);
    }

    messageDigest.digest.overload().implementation = function () {
        console.log("MessageDigest.digest() is called!");
        showStacks();
        var result = this.digest();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " digest result";
        toUtf8(tag, result);
        toHex(tag, result);
        toBase64(tag, result);
        console.log("=======================================================");
        return result;
    }
    messageDigest.digest.overload('[B').implementation = function (data) {
        console.log("MessageDigest.digest('[B') is called!");
        showStacks();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " digest data";
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        var result = this.digest(data);
        var tags = algorithm + " digest result";
        toUtf8(tag, result);
        toHex(tags, result);
        toBase64(tags, result);
        console.log("=======================================================");
        return result;
    }
    messageDigest.digest.overload('[B', 'int', 'int').implementation = function (data, start, length) {
        console.log("MessageDigest.digest('[B', 'int', 'int') is called!");
        showStacks();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " digest data";
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        var result = this.digest(data, start, length);
        var tags = algorithm + " digest result";
        toHex(tags, result);
        toBase64(tags, result);
        console.log("=======================================================", start, length);
        return result;
    }

    var mac = Java.use("javax.crypto.Mac");
    mac.init.overload('java.security.Key', 'java.security.spec.AlgorithmParameterSpec').implementation = function (key, AlgorithmParameterSpec) {
        console.log("Mac.init('java.security.Key', 'java.security.spec.AlgorithmParameterSpec') is called!");
        console.log("=======================================================");
        return this.init(key, AlgorithmParameterSpec);
    }
    mac.init.overload('java.security.Key').implementation = function (key) {
        console.log("Mac.init('java.security.Key') is called!");
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " init Key";
        var keyBytes = key.getEncoded();
        toUtf8(tag, keyBytes);
        toHex(tag, keyBytes);
        toBase64(tag, keyBytes);
        console.log("=======================================================");
        return this.init(key);
    }
    mac.update.overload('byte').implementation = function (data) {
        console.log("Mac.update('byte') is called!");
        return this.update(data);
    }
    mac.update.overload('java.nio.ByteBuffer').implementation = function (data) {
        console.log("Mac.update('java.nio.ByteBuffer') is called!");
        console.log("=======================================================");
        return this.update(data);
    }
    mac.update.overload('[B').implementation = function (data) {
        console.log("Mac.update('[B') is called!");
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " update data";
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        console.log("=======================================================");
        return this.update(data);
    }
    mac.update.overload('[B', 'int', 'int').implementation = function (data, start, length) {
        console.log("Mac.update('[B', 'int', 'int') is called!");
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " update data";
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        console.log("=======================================================", start, length);
        return this.update(data, start, length);
    }
    mac.doFinal.overload().implementation = function () {
        console.log("Mac.doFinal() is called!");
        var result = this.doFinal();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " doFinal result";
        toUtf8(tag, result);
        toHex(tag, result);
        toBase64(tag, result);
        console.log("=======================================================");
        return result;
    }
    mac.doFinal.overload('[B').implementation = function (data) {
        console.log("Mac.doFinal.overload('[B') is called!");
        return this.doFinal(data);
    }
    mac.doFinal.overload('[B', 'int').implementation = function (output, outOffset) {
        console.log("Mac.doFinal.overload('[B', 'int') is called!");
        console.log("=======================================================");
        return this.doFinal(output, outOffset);
    }

    var cipher = Java.use("javax.crypto.Cipher");
    cipher.init.overload('int', 'java.security.cert.Certificate').implementation = function () {
        console.log("Cipher.init('int', 'java.security.cert.Certificate') is called!");
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }
    cipher.init.overload('int', 'java.security.Key', 'java.security.SecureRandom').implementation = function () {
        console.log("Cipher.init('int', 'java.security.Key', 'java.security.SecureRandom') is called!");
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }
    cipher.init.overload('int', 'java.security.cert.Certificate', 'java.security.SecureRandom').implementation = function () {
        console.log("Cipher.init('int', 'java.security.cert.Certificate', 'java.security.SecureRandom') is called!");
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }
    cipher.init.overload('int', 'java.security.Key', 'java.security.AlgorithmParameters', 'java.security.SecureRandom').implementation = function () {
        console.log("Cipher.init('int', 'java.security.Key', 'java.security.AlgorithmParameters', 'java.security.SecureRandom') is called!");
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }
    cipher.init.overload('int', 'java.security.Key', 'java.security.spec.AlgorithmParameterSpec', 'java.security.SecureRandom').implementation = function () {
        console.log("Cipher.init('int', 'java.security.Key', 'java.security.spec.AlgorithmParameterSpec', 'java.security.SecureRandom') is called!");
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }
    cipher.init.overload('int', 'java.security.Key', 'java.security.AlgorithmParameters').implementation = function () {
        console.log("Cipher.init('int', 'java.security.Key', 'java.security.AlgorithmParameters') is called!");
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }

    cipher.init.overload('int', 'java.security.Key').implementation = function () {
        console.log("Cipher.init('int', 'java.security.Key') is called!");
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " init Key";
        var className = JSON.stringify(arguments[1]);
        if(className.indexOf("OpenSSLRSAPrivateKey") === -1){
            var keyBytes = arguments[1].getEncoded();
            toUtf8(tag, keyBytes);
            toHex(tag, keyBytes);
            toBase64(tag, keyBytes);
        }
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }
    cipher.init.overload('int', 'java.security.Key', 'java.security.spec.AlgorithmParameterSpec').implementation = function () {
        console.log("Cipher.init('int', 'java.security.Key', 'java.security.spec.AlgorithmParameterSpec') is called!");
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " init Key";
        var keyBytes = arguments[1].getEncoded();
        toUtf8(tag, keyBytes);
        toHex(tag, keyBytes);
        toBase64(tag, keyBytes);
        var tags = algorithm + " init iv";
        var iv = Java.cast(arguments[2], Java.use("javax.crypto.spec.IvParameterSpec"));
        var ivBytes = iv.getIV();
        toUtf8(tags, ivBytes);
        toHex(tags, ivBytes);
        toBase64(tags, ivBytes);
        console.log("=======================================================");
        return this.init.apply(this, arguments);
    }

    cipher.doFinal.overload('java.nio.ByteBuffer', 'java.nio.ByteBuffer').implementation = function () {
        console.log("Cipher.doFinal('java.nio.ByteBuffer', 'java.nio.ByteBuffer') is called!");
        console.log("=======================================================");
        return this.doFinal.apply(this, arguments);
    }
    cipher.doFinal.overload('[B', 'int').implementation = function () {
        console.log("Cipher.doFinal('[B', 'int') is called!");
        console.log("=======================================================");
        return this.doFinal.apply(this, arguments);
    }
    cipher.doFinal.overload('[B', 'int', 'int', '[B').implementation = function () {
        console.log("Cipher.doFinal('[B', 'int', 'int', '[B') is called!");
        console.log("=======================================================");
        return this.doFinal.apply(this, arguments);
    }
    cipher.doFinal.overload('[B', 'int', 'int', '[B', 'int').implementation = function () {
        console.log("Cipher.doFinal('[B', 'int', 'int', '[B', 'int') is called!");
        console.log("=======================================================");
        return this.doFinal.apply(this, arguments);
    }
    cipher.doFinal.overload().implementation = function () {
        console.log("Cipher.doFinal() is called!");
        console.log("=======================================================");
        return this.doFinal.apply(this, arguments);
    }

    cipher.doFinal.overload('[B').implementation = function () {
        console.log("Cipher.doFinal('[B') is called!");
        showStacks();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " doFinal data";
        var data = arguments[0];
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        var result = this.doFinal.apply(this, arguments);
        var tags = algorithm + " doFinal result";
        toUtf8(tags, result);
        toHex(tags, result);
        toBase64(tags, result);
        console.log("=======================================================");
        return result;
    }
    cipher.doFinal.overload('[B', 'int', 'int').implementation = function () {
        console.log("Cipher.doFinal('[B', 'int', 'int') is called!");
        showStacks();
        var algorithm = this.getAlgorithm();
        var tag = algorithm + " doFinal data";
        var data = arguments[0];
        toUtf8(tag, data);
        toHex(tag, data);
        toBase64(tag, data);
        var result = this.doFinal.apply(this, arguments);
        var tags = algorithm + " doFinal result";
        toUtf8(tags, result);
        toHex(tags, result);
        toBase64(tags, result);
        console.log("=======================================================", arguments[1], arguments[2]);
        return result;
    }

});

数字签名算法

签名

PrivateKey priK = getPrivateKey(str_priK);
Signature sig = Signature.getInstance("SHA256withRSA");
sig.initSign(priK);
sig.update(data);
sig.sign();

验证

PublicKey pubK = getPublicKey(str_pubK);
Signature sig = Signature.getInstance("SHA256withRSA");
sig.initVerify(pubK);
sig.update(data);
sig.verify(sign);

非对称加密算法

典型算法：RSA

RSA_Base64

数字签名算法

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