IMPLEMENTATION OF SHA-1 ALGORITHM using JAVA

AIM:

To  write a java program to calculate the message digest of a text using the SHA-1 algorithm

ALGORITHM:

Step 1: Input the plain text

Step 2: Append padding bits

Step 3: Append length

Step 4:Initialize  buffer.

Step 5: Process message in 512-bit (16word)blocks

Step 6: Encrypted in hexa decimal format

Step 7: Display the encrypted text.

PROGRAM:

importjava.security.*;

public class SHA1 {

public static void main(String[] a) {

try {

MessageDigest md = MessageDigest.getInstance("SHA1");

System.out.println("Message digest object info: ");

System.out.println(" Algorithm = " +md.getAlgorithm());

System.out.println(" Provider = " +md.getProvider());

System.out.println(" ToString = " +md.toString());

 String input = "";

md.update(input.getBytes());

byte[] output = md.digest();

System.out.println();

System.out.println("SHA1(\""+input+"\") = " +bytesToHex(output));

input = "abc";

md.update(input.getBytes());

output = md.digest();

System.out.println();

System.out.println("SHA1(\""+input+"\") = " +bytesToHex(output));

input = "abcdefghijklmnopqrstuvwxyz";

md.update(input.getBytes());

output = md.digest();

System.out.println();

System.out.println("SHA1(\"" +input+"\") = " +bytesToHex(output));

System.out.println(""); }

catch (Exception e) {

System.out.println("Exception: " +e);

 }

 }

public static String bytesToHex(byte[] b) {

 char hexDigit[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

StringBufferbuf = new StringBuffer();

for (int j=0; j<b.length; j++) {

buf.append(hexDigit[(b[j] >> 4) & 0x0f]);

buf.append(hexDigit[b[j] & 0x0f]); }

returnbuf.toString();

}

}

OUTPUT: