Android's RAS encryption algorithm test example _android

Copy Code code as follows:

Import Java.security.Key;
Import Java.security.KeyFactory;
Import Java.security.KeyPair;
Import Java.security.KeyPairGenerator;
Import Java.security.PrivateKey;
Import Java.security.PublicKey;
Import Java.security.interfaces.RSAPrivateKey;
Import Java.security.interfaces.RSAPublicKey;
Import Java.security.spec.PKCS8EncodedKeySpec;
Import Java.security.spec.X509EncodedKeySpec;

Import Javax.crypto.Cipher;

Import Sun.misc.BASE64Decoder;
Import Sun.misc.BASE64Encoder;


public class Rsahelper {


public static PublicKey Getpublickey (String key) throws Exception {
Byte[] keybytes;
Keybytes = (new Base64decoder ()). Decodebuffer (key);

X509encodedkeyspec Keyspec = new X509encodedkeyspec (keybytes);
Keyfactory keyfactory = keyfactory.getinstance ("RSA");
PublicKey PublicKey = Keyfactory.generatepublic (Keyspec);
return publickey;
}

public static Privatekey Getprivatekey (String key) throws Exception {
Byte[] keybytes;
Keybytes = (new Base64decoder ()). Decodebuffer (key);

Pkcs8encodedkeyspec Keyspec = new Pkcs8encodedkeyspec (keybytes);
Keyfactory keyfactory = keyfactory.getinstance ("RSA");
Privatekey Privatekey = keyfactory.generateprivate (Keyspec);
return privatekey;
}


public static String getkeystring (key key) throws Exception {
byte[] keybytes = key.getencoded ();
String s = (new Base64encoder ()). Encode (keybytes);
return s;
}


public static void Main (string[] args) throws Exception {

Keypairgenerator Keypairgen = keypairgenerator.getinstance ("RSA");
Number of key digits
Keypairgen.initialize (1024);
Key pair
KeyPair KeyPair = Keypairgen.generatekeypair ();

Public
PublicKey PublicKey = (rsapublickey) keypair.getpublic ();

Private
Privatekey Privatekey = (rsaprivatekey) keypair.getprivate ();

String publickeystring = getkeystring (PublicKey);
System.out.println ("public:\n" + publickeystring);

String privatekeystring = getkeystring (Privatekey);
System.out.println ("private:\n" + privatekeystring);

Encryption and Decryption class
Cipher Cipher = cipher.getinstance ("RSA");//cipher.getinstance ("rsa/ecb/pkcs1padding");

Plaintext
Byte[] PlainText = "We are all very well!" Mail: @sina. com ". GetBytes ();

Encryption
Cipher.init (Cipher.encrypt_mode, PublicKey);
byte[] Enbytes = cipher.dofinal (plaintext);

Get key through key string
PublicKey = Getpublickey (publickeystring);
Privatekey = Getprivatekey (privatekeystring);

Decrypt
Cipher.init (Cipher.decrypt_mode, Privatekey);
Byte[]debytes = Cipher.dofinal (enbytes);

publickeystring = getkeystring (PublicKey);
System.out.println ("public:\n" +publickeystring);

privatekeystring = getkeystring (Privatekey);
System.out.println ("private:\n" + privatekeystring);

string s = new string (debytes);
System.out.println (s);


}

}