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Message-ID: <20110414044418.GA24064@openwall.com>
Date: Thu, 14 Apr 2011 08:44:18 +0400
From: Solar Designer <solar@...nwall.com>
To: crypt-dev@...ts.openwall.com
Subject: Re: Answering and asking some of the first questions
On Wed, Apr 13, 2011 at 09:49:35AM -0300, Yuri Gonzaga wrote:
> 1. I have started to implement the bcrypt using SystemVerilog language and
> Altera's Quartus II design software. The ExpandKey of EksBlowFish is almost
> done, including SBoxes initialization, F function and the 18 rounds. Then, I
> will get into the setup stage and, later, finish the bcrypt.
Note that some parts of bcrypt are not actually performance critical -
you may leave those for the host system's CPU. In JtR's BF_std.c, only
this loop:
count = salt[4];
do {
...
} while (--count);
is performance-critical, or you may look at crypt_blowfish for simpler
code (lacking some optimizations not relevant to you):
http://www.openwall.com/crypt/
> 2. I am thinking of use the JTAG port avaiable in the development boards to
> receive the input parameters and send back the result. This a serial port
> that connects to a USB port on the Computer. Maybe, David has any suggestion
> to this part.
I assume it connects via an adapter. Sounds fine unless you've got a
more suitable port.
> 3. I have downloaded the JtR source code. In the "c3_fmt.c" file, there is a
> function named "crypt_all()", which looks like to be the right point where I
> will change the code to communicate to the hardware implementation. Input
> parameters are the strings "saved_key[index]" and "saved_salt", and output
> result is the string "crypt_out[index]".
You might also want to look at this sample:
http://cvsweb.openwall.com/cgi/cvsweb.cgi/Owl/packages/john/john/src/dummy.c
You'll need to define a new "format" and register it in john.c like it's
done for existing ones.
> Based in the article, where is the third input parameter, "cost"?
It's encoded in the salt string.
In BF_fmt.c and BF_std.c in JtR, the "cost" is decoded into salt[4]:
/*
* Binary salt type, also keeps the number of rounds.
*/
typedef BF_word BF_salt[4 + 1];
> There is an API to access the JTAG communication port inside the C code. So,
> I will pass the parameters through the JTAG port, the FPGA will calculate
> the hash and send it back to the computer. Finally, I will receive that in
> the JtR using the API I mentioned.
Sounds fine. These hashes are slow enough that the communication method
does not matter much.
> How do I can present the working code to you?
Since this initial task is closely related to JtR, you may create this
wiki page:
http://openwall.info/wiki/john/FPGA
and upload your files to there. To upload a file to the wiki, click on
the picture icon while editing the page.
Thanks,
Alexander
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