安卓逆向 -- 算法基础(数字签名)

public  static String  pubkey="MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDkluCxbqyIIVEG6wq3xwOncwtO" +
"Ew45xvjOdEuxBG5MCGIGfik7s2XB3Znz2ih7RWkQdOTWTLRfNKqGLCDXZrVfM6i6" +
"jJlxrPlHt8JlDPKmu5QGLsap5DGwdShnL29bLEpmql4UbxPo0NsCq91rt90m60H6" +
"4br6yURdv/Pr6jyOEQIDAQAB";
public  static String prikey="MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAOSW4LFurIghUQbr" +
"CrfHA6dzC04TDjnG+M50S7EEbkwIYgZ+KTuzZcHdmfPaKHtFaRB05NZMtF80qoYs" +
"INdmtV8zqLqMmXGs+Ue3wmUM8qa7lAYuxqnkMbB1KGcvb1ssSmaqXhRvE+jQ2wKr" +
"3Wu33SbrQfrhuvrJRF2/8+vqPI4RAgMBAAECgYEAoSn3FWIQZpIGzLfegJ/h5ado" +
"6wzoVLgCJ5062H1lPloSsr00WREsxzh0GMdRD0hqwN2JkcXWzeEV8S8foH6blEQ3" +
"Utycz1LzN8cOJRWlXz/+aPCjGMQKbAARXQOpY6LYj2Y9cB5OayoIh2/afsZbS6gv" +
"yJYZQNVDBGwmfJibEAECQQD7yE7gxwCHtjd8l/yhm87TROVaLUlq1jZXWsYNx8ts" +
"qq/gXUueIssn4b3VTof4Htog1ZE1kGcSNg4ccKIiH6KRAkEA6Gsc9uskNnqB/DdL" +
"SfvD5iZ03I4REAnpMueV9NHAA+cbOJtqSYUxEjW6jvzRo2MdqrlxOvRdUQZNKUZ+" +
"pzzzgQJBAM2B7X/ibjhXLmrv0zBFcEdZEKrOFAKz3Z7nZIiS7yM/HlbPT40/cPqY" +
"cs3MT4biB8CNEPzbZIWkwVfNR0j68UECQE3QfvQUqh0rSxXclXKBvobx3TJyxjeu" +
"ecs3SjebekRUPgLn1eAjndhQ8NMqxi2D48zjJYvtgMi96VumZIUtnQECQQCh46wV" +
"zSQ+iQcqBRipaNNa6ipAg1h60wh3omoBZQubQQYtDsmIbhT2AUZy6usBi65nd1I3" +
"UefrOu9gIHGeU3br";
public static PublicKey getPublickKey(String key)throws Exception{
byte[] keyBytes= new BASE64Decoder().decodeBuffer(key);
    X509EncodedKeySpec keys = new X509EncodedKeySpec(keyBytes);//实例化key
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    PublicKey publicKey = keyFactory.generatePublic(keys);
return publicKey;
}
public static PrivateKey getPrivatekey(String key)throws Exception{
byte[] bytes = new BASE64Decoder().decodeBuffer(key);
    PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(bytes);
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
return privateKey;
}
public static byte[] encrypt(byte[] enstr)throws Exception{
    PublicKey publickKey = getPublickKey(pubkey);
    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
    cipher.init(Cipher.ENCRYPT_MODE,publickKey);
byte[] bytes = cipher.doFinal(enstr);
return bytes;
}
public static byte[] decrypt(byte[] destr)throws Exception{
    PrivateKey privatekey = getPrivatekey(prikey);
    Cipher cipht = Cipher.getInstance("RSA/ECB/PKCS1Padding");
    cipht.init(Cipher.DECRYPT_MODE,privatekey);
byte[] bytes= cipht.doFinal(destr);
return bytes;
}
public static byte[] sign(byte[] bytes)throws Exception{
    PrivateKey privatekey = getPrivatekey(prikey);
    Signature sig = Signature.getInstance("SHA256withRSA");
    sig.initSign(privatekey);
    sig.update(bytes);
return sig.sign();
}
public static boolean verify(byte[] bytes,byte[] sign)throws Exception{
    PublicKey publickKey = getPublickKey(pubkey);
    Signature sig = Signature.getInstance("SHA256withRSA");
    sig.initVerify(publickKey);
    sig.update(bytes);
return sig.verify(sign);
}
public static void main(String[] args) throws Exception{
    System.out.println("逆向有你");
    String bs= "逆向有你a";
byte[] signs = sign(bs.getBytes(StandardCharsets.UTF_8));
    System.out.println("数字签名（字节）："+Arrays.toString(signs));
    System.out.println("数字签名（Hex）："+bytes2HexString(signs));
    System.out.println("数字签名（Base64）："+Base64.getEncoder().encodeToString(signs));
boolean bl=verify(bs.getBytes(StandardCharsets.UTF_8),signs);
    System.out.println("验证结果："+bl);
}
运行结果：
数字签名（字节）：[26, -47, -18, 125, -106, -61, -56, -89, -97, 17, -16, -119, -86, 126, -81, -101, -91, -6, 5, -91, 93, 26, -11, -65, -84, 85, -112, -82, -123, -35, -115, 55, -113, -37, 80, -127, -128, -37, -78, 17, -45, -116, -4, 59, -103, -115, 27, 85, 69, -100, 23, 25, -33, 67, 88, -34, -59, 78, 18, 6, 57, -39, 54, -73, 100, -59, 77, 91, 75, -119, 118, 89, 95, 94, -82, -101, -74, -55, -15, -34, -9, -3, -93, -42, 22, 44, -7, -58, -116, -125, 78, 37, -25, 120, -58, -93, 86, 3, -30, -7, 55, 30, 45, 36, -112, -42, -104, 106, 1, -103, -24, 35, 60, 18, -71, -114, 83, 46, 107, 48, 16, -88, 113, -77, 46, 124, -92, -50]
数字签名（Hex）：1AD1EE7D96C3C8A79F11F089AA7EAF9BA5FA05A55D1AF5BFAC5590AE85DD8D378FDB508180DBB211D38CFC3B998D1B55459C1719DF4358DEC54E120639D936B764C54D5B4B8976595F5EAE9BB6C9F1DEF7FDA3D6162CF9C68C834E25E778C6A35603E2F9371E2D2490D6986A0199E8233C12B98E532E6B3010A871B32E7CA4CE
数字签名（Base64）：GtHufZbDyKefEfCJqn6vm6X6BaVdGvW/rFWQroXdjTeP21CBgNuyEdOM/DuZjRtVRZwXGd9DWN7FThIGOdk2t2TFTVtLiXZZX16um7bJ8d73/aPWFiz5xoyDTiXneMajVgPi+TceLSSQ1phqAZnoIzwSuY5TLmswEKhxsy58pM4=
验证结果：true

var signData="逆向有你a";
var pubkey1="-----BEGIN PUBLIC KEY-----\n" +
"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQD3XSdz1MnzazBEN5KOfTx0IyVJ\n" +
"Z5wb57isrCuHDhnYXwtmdhQalgII0fozeeFpMpAvlnmHC1kpW7XVGvZnLx3bWbCE\n" +
"bf+pMSW4kmQuI+5cxRUJbCl7sdaODBrINgERHPICVC18AJLThEVMHyjuR6Jn4zQm\n" +
"yYNbReSktY/BrFTvMQIDAQAB\n" +
"-----END PUBLIC KEY-----";
var privatekey="-----BEGIN PRIVATE KEY-----\n" +
"MIICeAIBADANBgkqhkiG9w0BAQEFAASCAmIwggJeAgEAAoGBAPddJ3PUyfNrMEQ3\n" +
"ko59PHQjJUlnnBvnuKysK4cOGdhfC2Z2FBqWAgjR+jN54WkykC+WeYcLWSlbtdUa\n" +
"9mcvHdtZsIRt/6kxJbiSZC4j7lzFFQlsKXux1o4MGsg2AREc8gJULXwAktOERUwf\n" +
"KO5HomfjNCbJg1tF5KS1j8GsVO8xAgMBAAECgYEA6eG1JMrj63jEmStmMb1txG1a\n" +
"mu4Q5z2QGgtr2HVXsIIlGEq6tWxyHf7TL4qkuz9onuYKn8n2Eqm44fZtVaBx+5ES\n" +
"zRpIvlTvaxmVu0HZ1hYAzUw1XyRnXNMKpL5tT4GCjm8+QGPzlGxgXI1sNg8r9Jaw\n" +
"9zRUYeA6LQR9RIMkHWUCQQD8QojjVoGjtiunoh/N8iplhUszZIavAEvmDIE+kVy+\n" +
"pA7hvlukLw6JMc7cfTcnHyxDo9iHVIzrWlTuKRq9KWVLAkEA+wgJS2sgtldnCVn6\n" +
"tJKFVwsHrWhMIU29msPPbNuWUD23BcKE/vehIyFu1ahNA/TiM40PEnzprQ5JfPxU\n" +
"16S78wJANTfMLTnYy7Lo7sqTLx2BuD0wqjzw9QZ4/KVytsJv8IAn65P/PVn4FRV+\n" +
"8KEx+3zmF7b/PT2nJRe/hycAzxtmlQJBAMrFwQxEqpXfoAEzx4lY2ZBn/nmaR/SW\n" +
"4VNEXCbocVC7qT1j1R5HVMgV13uKiTtq8dUGWmhqsi7x3XayNK5ECPUCQQDZaAN6\n" +
"tvIHApz9OLsXSw0jZirQ6KEYdharXbIVDy1W1sVE3lzLbqLdFp1bxAHQIvsYS5PM\n" +
"A9veSJh372RLJKkj\n" +
"-----END PRIVATE KEY-----";
function signa(src){
let signature=new KJUR.crypto.Signature({alg:"SHA256withRSA",prvkeypem:privatekey});   
    signature.updateString(src);
let a = signature.sign();
let sign = hextob64(a);
console.log(sign);
}
function signa1(src){
var key = KEYUTIL.getKey(privatekey);
var signature=new KJUR.crypto.Signature({alg:"SHA256withRSA"});
    signature.init(key);
    signature.updateString(src);
var a = signature.sign();
var sign = hextob64(a);
console.log(sign);
return sign;
}
function yanzheng(){
var a=signa1(signData);
var signatureVf = new KJUR.crypto.Signature({alg:"SHA256withRSA",prvkeypem:pubkey1});
    signatureVf.updateString(signData);
var b = signatureVf.verify(b64tohex(a));
console.log("jsrsasign verify: "+b);
}
signa1(signData)
yanzheng()