In this post, we will learn how we can implement String/Password Base64 Encrypt and Base64 Decrypt as well as Hexadecimal (Base 16) Encrypt and Hexadecimal (Base 16) Decrypt with the help of a jar which is EncryptDecryptA143mk.jar Consists of 4 functions/methods understand its working as follows.

ppackage EncryptDecryptA143mk; import java.io.UnsupportedEncodingException; import java.security.NoSuchAlgorithmException; public class TestEncryptDecryptA143mk { public static void main(String args []) throws Exception { try { EncryptDecryptA143mk td= new EncryptDecryptA143mk(); /* Base64EEncryptDecrypt*/ String encrypted=td.EncryptA143MK("https://a143mk.blogspot.com"); String decrypted=td.DecryptA143MK(encrypted); System.out.println("\n*******Base64 String To EncryptDecrypt *******"); System.out.println("Base64 Encrypted String: " + encrypted); System.out.println("Base64 Decrypted String: " + decrypted); /* Hexadecimal EncryptDecrypt */ String encryptedMd5=td.HexDecryptA143MK("https://a143mk.blogspot.com"); String decryptedMd5=td.HexEncryptA143MK(encryptedMd5); System.out.println("\n*******Hexadecimal String To EncryptDecrypt *******"); System.out.println("Hexadecimal Encrypted of string: " + encryptedMd5); System.out.println("Hexadecimal Decrypted of string: " + decryptedMd5 ); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
Output:

MD5:
MD5 algorithm is a cryptography hash function producing a 128-bit (16-byte) hash value, typically expressed in text format as a 32 digit hexadecimal number. do non mistake hashing algorithms with encryption algorithm.

package encryption; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; /** * * @author Manoj */ class AeSimpleMD5 { private static String convertToHex(byte[] data) { StringBuffer buf = new StringBuffer(); for (int i = 0; i < data.length; i++) { int halfbyte = (data[i] >>> 4) & 0x0F; int two_halfs = 0; do { if ((0 <= halfbyte) && (halfbyte <= 9)) buf.append((char) ('0' + halfbyte)); else buf.append((char) ('a' + (halfbyte - 10))); halfbyte = data[i] & 0x0F; } while(two_halfs++ < 1); } return buf.toString(); } public static String MD5(String text) throws NoSuchAlgorithmException, UnsupportedEncodingException { MessageDigest md; md = MessageDigest.getInstance("MD5"); byte[] md5hash = new byte[32]; md.update(text.getBytes("iso-8859-1"), 0, text.length()); md5hash = md.digest(); return convertToHex(md5hash); } } public class MD5encryption { public static void main(String[] args) throws IOException { BufferedReader userInput = new BufferedReader (new InputStreamReader(System.in)); System.out.println("Enter string:"); String rawString = userInput.readLine(); try { System.out.println("MD5 hash of string: " + AeSimpleMD5.MD5(rawString)); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
Output:

Base64 is a group of similar binary-to-text encoding schemes that represent binary data in an ASCII (American Standard Code for Information Interchange) string format by translating it into a radix-64 representation.  The term Base64 originates from a specific MIME (Multipurpose Internet Mail Extensions) content transfer encoding.The encoded string with above characters is safe to be transferred over network supporting text data without fear of losing data in confusion of control characters.It is most popular form of the “Base Encoding”.
The following is the character subset of US-ASCII that is used for Base64.
 [a-z] – 26 characters
 [A-Z] – 26 characters
 [0-9] – 10 characters
 [+] - 1 character [filler character]
 [/] - 1 character [filler character]
 [=] - Used for Padding purposes, as explained later.

Encoding a string to base 64
This is as simple as getting an instance of encoder and input the string as bytes to encode it.

String str = "Manoj@Kumar.com";// Encode data using BASE64 String encoded = DatatypeConverter.printBase64Binary(str.getBytes());

 Decoding a string to base 64
This is also very simple. Just get the instance of Base64.Decoder and use it to decode the base 64 encoded string.

String str = "TWFub2pAS3VtYXIuY29t"; // Decode data using BASE64 String decoded = new String(DatatypeConverter.parseBase64Binary(str));

import java.io.*; import javax.xml.bind.*; public class EncodeString64 { public static void main(String[] args) throws UnsupportedEncodingException { String str = "Manoj@Kumar.com"; // encode data using BASE64 String encoded = DatatypeConverter.printBase64Binary(str.getBytes()); System.out.println("Encoded value is \t" + encoded); // Decode data String decoded = new String(DatatypeConverter.parseBase64Binary(encoded)); System.out.println("Decoded value is \t" + decoded); System.out.println("Original value is \t" + str); } }

Output:      
                                              Encoded value is          TWFub2pAS3VtYXIuY29t
                                              Decoded value is          Manoj@kumar.com
                                              Original value is           Manoj@kumar.com