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Message-ID: <90454692ddbe4b7f2587ed221a9d2bfd@smtp.hushmail.com> Date: Mon, 27 Jul 2015 11:33:31 +0200 From: magnum <john.magnum@...hmail.com> To: john-dev@...ts.openwall.com Subject: Re: auditing our use of FMT_* flags On 2015-07-27 10:27, Kai Zhao wrote: > formats.h: 51~60 > > /* > * This flag must be set for formats that do UCS-2, UTF-16 or some other > wide > * encoding internally (eg. most Microsoft formats). The most common problem > * with formats not fully Unicode-aware is when a format like this is > hard-coded > * to convert from ISO-8859-1 (ie. by just inserting 0x00, effectively just > * casting every char to a short). Such formats MUST set FMT_UNICODE and > MUST > * NOT set FMT_UTF8, or users will get false negatives when using UTF-8 or > * codepages. > */ > #define FMT_UNICODE 0x00000004 > > "Such formats MUST set FMT_UNICODE and MUST NOT set FMT_UTF8" > Here "Such formats" points to "The most common problem with formats..." ? > > Can anyone explain this ? Is there any example ? > > I have found that there are only two formats which set FMT_UNICODE and > NOT set FMT_UTF8. They are: > > opencl_mscash_fmt_plug.c, opencl_nt_fmt_plug.c This means they can currently only convert ISO-8859-1 to UTF-16/UCS-2. This is how Hashcat and most other crackers do it, because it's simple and fast code. > There are 27 formats which both set FMT_UNICODE and SET FMT_UTF8. This means they can convert any supported encoding to UTF-16/UCS-2. That involves a lot more code. The flags ensure we bail with error instead of chugging along with false negatives: $ ../run/john -form:nt-opencl test.in -w:rockyou_utf8.lst -enc:utf8 This format does not yet support other encodings than ISO-8859-1 $ ../run/john -form:nt-opencl test.in -w:rockyou_8859_1.lst -enc:8859-1 Loaded 1 password hash (nt-opencl, NT [MD4 OpenCL]) Press 'q' or Ctrl-C to abort, almost any other key for status 0g 0:00:00:00 DONE (2015-07-27 11:29) 0g/s 7708p/s 7708c/s 7708C/s elles1992..Vk122503 Session completed magnum
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