Java常用加密算法应用MD5，SHA，RSA

protected byte[] encrypt(byte[] obj) ...{

try ...{

MessageDigest md5 = MessageDigest.getInstance("MD5");

md5.update(obj);

return md5.digest();

} catch (NoSuchAlgorithmException e) ...{

e.printStackTrace();

}

}

protected byte[] encrypt(byte[] obj) ...{

try ...{

MessageDigest sha = MessageDigest.getInstance("SHA");

sha.update(obj);

return sha.digest();

} catch (NoSuchAlgorithmException e) ...{

e.printStackTrace();

}

}

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.interfaces.RSAPrivateKey;

import java.security.interfaces.RSAPublicKey;
import javax.crypto.Cipher;
/** *//**

* <b>RSAEncrypt</b>

* <p>

* @author maqujun

* @see

*/

public class RSAEncrypt ...{
/** *//**

* Main method for RSAEncrypt.

* @param args

*/

public static void main(String[] args) ...{

try ...{

RSAEncrypt encrypt = new RSAEncrypt();



String encryptText = "encryptText";

KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");

keyPairGen.initialize(1024);

KeyPair keyPair = keyPairGen.generateKeyPair();

// Generate keys

RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();



byte[] e = encrypt.encrypt(publicKey, encryptText.getBytes());

byte[] de = encrypt.decrypt(privateKey,e);

System.out.println(encrypt.bytesToString(e));

System.out.println(encrypt.bytesToString(de));

} catch (Exception e) ...{

e.printStackTrace();

}

}



/** *//**

* Change byte array to String.

* @return byte[]

*/

protected String bytesToString(byte[] encrytpByte) ...{

String result = "";

for (Byte bytes : encrytpByte) ...{

result += (char) bytes.intValue();

}

return result;

}



/** *//**

* Encrypt String.

* @return byte[]

*/

protected byte[] encrypt(RSAPublicKey publicKey, byte[] obj)  ...{

if (publicKey != null) ...{

try ...{

Cipher cipher = Cipher.getInstance("RSA");

cipher.init(Cipher.ENCRYPT_MODE, publicKey);

return cipher.doFinal(obj);

} catch (Exception e) ...{

e.printStackTrace();

}

}

return null;

}
/** *//**

* Basic decrypt method

* @return byte[]

*/

protected byte[] decrypt(RSAPrivateKey privateKey, byte[] obj) ...{

if (privateKey != null) ...{

try ...{

Cipher cipher = Cipher.getInstance("RSA");

cipher.init(Cipher.DECRYPT_MODE, privateKey);

return cipher.doFinal(obj);

} catch (Exception e) ...{

e.printStackTrace();

}

}



return null;

}

}