It’s possible, in an applet, that this code won’t work for
some Netscape Navigator versions, because they don’t have the
MessageDigest class included (perhaps this only concerns European
versions, because of some export restrictions to cryptographic code).
In that case, as far as I know, the only way to implement the SHA
is to follow Steve Reid’s originial C++ code step by step. But
there also exist some Java translations on the Net.
How It Works
You just call makeSHA("Hello World!"), and you’ll get
back a string consisting of the hex-view of the encoded bytes.
import java.io.*;
import java.lang.*;
import java.security.*;
import java.util.*;
public class mysha {
public static String toHexString(byte b)
{
int value = (b & 0x7F) + (b < 0 ? 128 : 0);
String ret = (value < 16 ? "0" : "");
ret += Integer.toHexString(value).toUpperCase();
return ret;
}
public static String makeSHA(String inputstring) {
String outputstring="";
try
{
// Objekt mit SHA" holen => initialize SHA object
MessageDigest md = MessageDigest.getInstance("SHA");
byte[] myText = inputstring.getBytes();
md.update(myText);
// Berechnen => Calculate
byte[] result = md.digest();
// Ausgeben => Output
for (int i = 0; i < result.length; ++i) {
outputstring=outputstring+toHexString(result[i]);
}
}
catch ( Exception e) {
System.out.println("Error"+e);
}
return outputstring;
}
public static void main(String arguments[]) {
// runs test-vector "abc"
System.out.println(makeSHA("abc"));
}
}
About the Author
Andreas Brandmaier
is a student at the University of Munich, working with statistical
databases using Perl and Java.
Java users are encouraged to submit samples of useful code for publication in the pages of Gamelan. Send your files and comments to editor@developer.com for consideration. Thank you.
