SHA1 Algorithm(Using Java)

SHA is a cryptographic message digest algorithm similar to MD5. SHA-1 hash considered to be one of the most secure hashing functions, producing a 160-bit digest (40 hex numbers) from any data with a maximum size of 2⁶⁴ bits. While Java has built in classes to compute SHA 1 hash, it's quite uneasy to use them for a simple task -- calculate SHA-1 hash and return 40 byte hexadecimal string.


Hello Buddies  here is the small example of the SHA1 algorithm using Java..

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class SHADemo {
 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)));
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class SHADemo {
 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 SHA1(String text)
throws NoSuchAlgorithmException, UnsupportedEncodingException  {
MessageDigest md;
md = MessageDigest.getInstance("SHA-1");
byte[] sha1hash = new byte[40];
md.update(text.getBytes("iso-8859-1"), 0, text.length());
sha1hash = md.digest();
return convertToHex(sha1hash);
}
public static void main(String ar[]) throws Exception
{
        String sha1_ad1 = SHADemo.SHA1("encryptme");
        System.out.println(sha1_ad1);

}
}
out put is..
99552371f24b195043148eb3e59d9fe84eb7efea