Android md5 encryption and rsa encryption and decryption implementation code

Source: Internet
Author: User
Tags md5 encryption modulus

Copy codeThe Code is as follows: import java. io. UnsupportedEncodingException;
Import java. security. MessageDigest;
Import java. security. NoSuchAlgorithmException;
Public class MD5 {
/*
* MD5 Encryption
*/
Public static String getDigest (String str ){
MessageDigest messageDigest = null;
Try {
MessageDigest = MessageDigest. getInstance ("MD5 ");
MessageDigest. reset ();
MessageDigest. update (str. getBytes ("UTF-8 "));
} Catch (NoSuchAlgorithmException e ){
E. printStackTrace ();
} Catch (UnsupportedEncodingException e ){
E. printStackTrace ();
}
Byte [] byteArray = messageDigest. digest ();
StringBuffer md5StrBuff = new StringBuffer ();
For (int I = 0; I <byteArray. length; I ++ ){
If (Integer. toHexString (0xFF & byteArray [I]). length () = 1)
Md5StrBuff. append ("0"). append (Integer. toHexString (0xFF & byteArray [I]);
Else
Md5StrBuff. append (Integer. toHexString (0xFF & byteArray [I]);
}
Return md5StrBuff. toString (). toUpperCase ();
}
}

Copy codeThe Code is as follows: import java. math. BigInteger;
Import java. security. Key;
Import java. security. KeyFactory;
Import java. security. PublicKey;
Import java. security. spec. RSAPublicKeySpec;
Import javax. crypto. Cipher;
Import org. bouncycastle. jce. provider. BouncyCastleProvider;
Public class RSAUtil {
/**
* Encryption
*
* @ Param message
* @ Return
*/
Public static String encrypt (String message ){
Byte [] result = null;
Try {
Result = encrypt (message, getPublicKey ());
} Catch (Exception e ){
E. printStackTrace ();
}
Return toHexString (result );
}
/**
* Decryption
*
* @ Param message
* @ Return
*/
Public static String decrypt (String message ){
Byte [] result = null;
Try {
Result = decrypt (message, getPublicKey ());
} Catch (Exception e ){
E. printStackTrace ();
}
Return new String (result );
}
/**
* Encryption (public key encryption and private key encryption)
*
* @ Param message refers to the message to be encrypted.
* @ Param key public key or private key
* @ Return
* @ Throws Exception
*/
Private static byte [] encrypt (String message, Key key) throws Exception {
Cipher cipher = Cipher. getInstance ("RSA", new BouncyCastleProvider ());
Cipher. init (Cipher. ENCRYPT_MODE, key );
// Handle Chinese Characters
Return cipher. doFinal (message. getBytes ("gb2312 "));
}
/**
* Decryption (if the public key is encrypted, the private key is used for decryption; if the private key is encrypted, the public key is used for decryption)
*
* @ Param message refers to the message to be decrypted.
* @ Param key public key or private key
* @ Return
* @ Throws Exception
*/
Private static byte [] decrypt (String message, Key key) throws Exception {
Cipher cipher = Cipher. getInstance ("RSA", new BouncyCastleProvider ());
Cipher. init (Cipher. DECRYPT_MODE, key );
Return cipher. doFinal (toBytes (message ));
}
/**
* Obtain the Public Key through the module length and Public Key Index
*
* @ Param modulus mode length
* @ Param publicExponent Public Key Index
* @ Return
* @ Throws Exception
*/
Public static PublicKey getPublicKey (){
PublicKey publicKey = null;
String modulus = "140865665237544398577638791993321201143991791099370252934699963963887058026979531275917645451893685346013654333931757603593193739776986525943697469996693704995753266331593233395038088698299308180612215713544577462613426793519824197226393059683065343801412208205295045502348474411031999124137863144916358656019 ";
String publicExponent = "65537 ";
BigInteger m = new BigInteger (modulus );
BigInteger e = new BigInteger (publicExponent );
RSAPublicKeySpec keySpec = new RSAPublicKeySpec (m, e );
Try {
KeyFactory keyFactory = KeyFactory. getInstance ("RSA", new BouncyCastleProvider ());
PublicKey = keyFactory. generatePublic (keySpec );
} Catch (Exception e1 ){
E1.printStackTrace ();
}
Return publicKey;
}
Private static final byte [] toBytes (String s ){
Byte [] bytes;
Bytes = new byte [s. length ()/2];
For (int I = 0; I <bytes. length; I ++ ){
Bytes [I] = (byte) Integer. parseInt (s. substring (2 * I, 2 * I + 2), 16 );
}
Return bytes;
}
Public static String toHexString (byte [] B ){
StringBuilder sb = new StringBuilder (B. length * 2 );
For (int I = 0; I <B. length; I ++ ){
Sb. append (HEXCHAR [(B [I] & 0xf0) >>> 4]);
Sb. append (HEXCHAR [B [I] & 0x0f]);
}
Return sb. toString ();
}
Private static char [] HEXCHAR = {'0', '1', '2', '3', '4', '5', '6', '7 ', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F '};
}

Copy codeThe Code is as follows: import android. app. Activity;
Import android. OS. Bundle;
Import android. util. Log;
Public class MainActivity extends Activity {
@ Override
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. main );
String info = "I don't know when to like it. I will come to see you every night. ";
Log. d ("zhangxy", MD5.getDigest (info ));
// Public key encryption
Log. d ("zhangxy", RSAUtil. encrypt (info ));
// Public Key decryption (encrypted by private key)
Log. d ("zhangxy", RSAUtil. decrypt ("decrypt "));
}
}

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.