Date: Sun, 18 Dec 2011 16:38:10 +0530 From: piyush mittal <piyush.cse29@...il.com> To: john-dev@...ts.openwall.com Subject: Re: Bit slice implementation of DES based hashes At last a new twist came. The character equivalent of Ox0123456789ABCDEF is a sequence of special characters i.e NON ASCII.Therefore it is mandatory to use Unicode in oracle and then I hope we also need to change whole code of Bit slice DES to Unicode because there every calculation is going on with respect to ASCII char only . On Sun, Dec 18, 2011 at 6:38 AM, piyush mittal <piyush.cse29@...il.com>wrote: > You really don't need salts and iterations of DES_bs_crypt(). You need >> different ones, which you may implement externally to your slight >> revision of DES_bs_crypt_LM(). >> > > Yes *Of course.*May be today I will be able to finish out the whole work*. > * > > > Thanks > > > > > > On Sun, Dec 18, 2011 at 3:54 AM, Solar Designer <solar@...nwall.com>wrote: > >> On Sat, Dec 17, 2011 at 10:01:24PM +0530, piyush mittal wrote: >> > Yes, that is true that we can call DES_bs_set_key() with same fixed key >> > for all layers.But what about different plain text that we need i.e if >> we >> > see into struct fmt_main initialisation it sends all stored list of >> > password through method set_key(). >> >> Just because the format method is named set_key() doesn't imply that it >> has to call DES_bs_set_key(). In your case, it sounds like it should not. >> Instead, according to what you're saying, it should either initialize a >> bit layer in B or it should save the password as-is e.g. in a >> saved_key entry (like some formats do) and then have crypt_all() >> process those passwords into their bit layers in B before calling a >> revision of DES_bs_crypt_LM(). >> >> > > As I suggested, DES_bs_crypt_LM() is a closer match. DES_bs_crypt() >> > > adds salts and iterations, which you don't need. >> > >> > No.Salt and iterations also exist in oracle.Salt here is user name and >> we >> > need two iterations. >> >> You really don't need salts and iterations of DES_bs_crypt(). You need >> different ones, which you may implement externally to your slight >> revision of DES_bs_crypt_LM(). >> >> > Let me summarise you what actually going on. >> > >> > 1.Concatenate user name(i.e salt) and password to get plain text >> string(i.e >> > input plain text for DES). >> > 2.Encrypt plain text string in CBC mode using fixed key >> 0x0123456789ABCDEF. >> > 3.Encrypt the plain text string again in CBC mode but using the last >> block >> > of o/p of previous step as the encryption key. >> > >> > so if I will apply DES_bs_crypt_LM() then step 2 can be done but step 3 >> > again needs number of modifications >> >> Please don't worry about efficiency for your initial implementation. >> When you don't worry about efficiency, you can just use a trivial >> revision of DES_bs_crypt_LM() (with B initialization removed) for both >> step 2 and step 3 above. You will need to replace K between steps 2 and >> 3, but you can do it externally to the function. >> >> Of course, the goal of bitslicing is to improve performance, so you will >> need to worry about it at some point, but initially your goal is just to >> get things working. >> >> Thanks, >> >> Alexander >> > > > > -- > Piyush Mittal > Department of Computer Science and Engineering > National Institute of Technology,Rourkela > INDIA > > > -- Piyush Mittal Department of Computer Science and Engineering National Institute of Technology,Rourkela INDIA Content of type "text/html" skipped
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