Re: Problem with MD5

Henry wrote:
> Hi,
>
> I try to create a finger print of a simple String with MessageDigest.
> I want to have a 128 digit fingerprint with numbers and letters
> but I receive just some ugly crap like Ÿ/þ¡³ù±íK.§—¬d¿.
> Please somebody tell me how I can get the beautiful 128 digit
> fingerprint as a String out of a byte array.
>
> MessageDigest md5 = MessageDigest.getInstance("MD5");
> md5.update("A stupid programmer".getBytes());
> System.out.println(new String(md5.digest()));

It's binary data, so conversion to String using the default encoding
is not likely to give you what you want. You could try converting to
hexadecimal:

byte[] digest=md5.digest();
StringBuffer sb=new StringBuffer();
for (int jj=0; jj<digest.length; ++jj) {
// Append two hexadecimal digits for each byte.
sb.append("0123456789ABCDEF".charAt((digest[jj]>>4) & 0x0F));
sb.append("0123456789ABCDEF".charAt(digest[jj] & 0x0F));
}
System.out.println(sb.toString());

--Mike Amling

Even easier, if you don't need leading zeros:

byte[] digest=md5.digest();
String hex = (new BigInteger(1, digest)).toString(16);

JK.

Michael Amling wrote:
> Henry wrote:
>
>> Hi,
>>
>> I try to create a finger print of a simple String with MessageDigest.
>> I want to have a 128 digit fingerprint with numbers and letters but I
>> receive just some ugly crap like Ÿ/þ¡³ù±íK.§—¬d¿.
>> Please somebody tell me how I can get the beautiful 128 digit
>> fingerprint as a String out of a byte array.
>>
>> MessageDigest md5 = MessageDigest.getInstance("MD5");
>> md5.update("A stupid programmer".getBytes());
>> System.out.println(new String(md5.digest()));
>
>
> It's binary data, so conversion to String using the default encoding
> is not likely to give you what you want. You could try converting to
> hexadecimal:
>
> byte[] digest=md5.digest();
> StringBuffer sb=new StringBuffer();
> for (int jj=0; jj<digest.length; ++jj) {
> // Append two hexadecimal digits for each byte.
> sb.append("0123456789ABCDEF".charAt((digest[jj]>>4) & 0x0F));
> sb.append("0123456789ABCDEF".charAt(digest[jj] & 0x0F));
> }
> System.out.println(sb.toString());
>
> --Mike Amling
>