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'};

StringBuffer buf = new StringBuffer();

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

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

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

}

return buf.toString();

}