将Java sha512crypt转换为C＃

Question

I am trying to duplicate the following JAVA code into C# but I don't think I'm doing it right o_o

(The code is taken from ftp://ftp.arlut.utexas.edu/pub/java_hashes/Sha512Crypt.java )

JAVA variables:

ctx, alt_ctx = MessageDigest

key = String (the password to hash)

salt = String (salt to add to the hash)

        /*                  ---JAVA---                    //
        ////////////////////////////////////////////////////
        ctx.reset();

        ctx.update(key, 0, key.length);
        ctx.update(salt, 0, salt.length);

        alt_ctx.reset();
        alt_ctx.update(key, 0, key.length);
        alt_ctx.update(salt, 0, salt.length);
        alt_ctx.update(key, 0, key.length);

        alt_result = alt_ctx.Digest();
        //////////////////////////////////////////////////*/

C# variables:

ctx, alt_ctx = HashAlgorithm (SHA512Managed)

key and salt are same as in JAVA...

 //                       --- C# EQUIV ? ---                    //
        int TESTINGINT;
        ctx = null;
        ctx = new SHA512Managed();
        ctx.TransformBlock(key, 0, key.Length, key, 0);
        ctx.TransformBlock(salt, 0, salt.Length, salt, 0);

        alt_ctx = null;
        alt_ctx = new SHA512Managed();

        alt_ctx.TransformBlock(key, 0, key.Length, key, 0);
        alt_ctx.TransformBlock(salt, 0, salt.Length, salt, 0);
        alt_ctx.TransformBlock(key, 0, key.Length, key, 0);

        alt_result = alt_ctx.TransformFinalBlock(key, 0, key.Length); //most likely wrong here

        //?????????????????????????????????????????????????????????//

Like I said, pretty sure this is wrong... Wondering if anyone knows the exact translation.

I've also been looking at http://www.obviex.com/samples/hash.aspx for some help. This however does not give me the same output and does not have any # rounds to do.

Given the word "beta" I'm trying to ultimately replicate the following (one line)

$6$rounds=60000$ZIFtW/dNUcD/k$O57sTkYwuRpQcgpnIdKLShfCVR7.vGzfMhvvWn7Mg8trGJsWADChhs6S5ONybnSBWHEHIQKw66a4i/YrA4y/y1

Thanks for your help

Answer 1

So after doing some thorough testing, I've fixed my C# to the following which seems to be the equivalent...

ctx = new SHA512Managed();

byte[] digestA = new byte[key.Length + salt.Length];

ctx.TransformBlock(key, 0, key.Length, digestA, 0);
ctx.TransformBlock(salt, 0, salt.Length, digestA, key.Length);

byte[] digestB = new byte[key.Length * 2 + salt.Length];

ctx.TransformBlock(key, 0, key.Length, digestB, 0);
ctx.TransformBlock(salt, 0, salt.Length, digestB, key.Length);
ctx.TransformBlock(key, 0, key.Length, digestB, key.Length + salt.Length);

alt_ctx = new SHA512Managed();

alt_result = alt_ctx.ComputeHash(digestB);