CODEWITHSUNDEEP
javaarraysmd5unsigned-integer
Fatima Tariq
Fatima Tariq

Reputation: 89

How to convert byte array to unsigned 128 bit integer in Java?

I am trying to hash strings using MD5. I need the hashed value as a 128 bit unsigned integer in Java.

MessageDigest md = MessageDigest.getInstance("MD5");

String toHash = "HashThis";
md.update(toHash.getBytes());
byte[] isHashed = md.digest();

How do I convert isHashed to an integer?

Upvotes: 0

Views: 1564

Answers (2)

Kayaman
Kayaman

Reputation: 73568

Use BigInteger.

BigInteger value = new BigInteger(isHashed);

To ensure that the resulting value is positive (as the byte array is expected to be in 2's complement), make sure the most significant bit is zero. This can be easily achieved by making the array 1 element bigger, with the first byte being 0.

Upvotes: 1

lodo
lodo

Reputation: 2383

Java does not have a 128 bit int type. But it has a BigInteger class, which have a constructor that takes a signum and a magnitude expressed as a byte[], as you require.

BigInteger value=new BigInteger(1,isHashed);

Upvotes: 1

Related Questions