RE: [Passwordsafe-devel] Symbian port?

[Rony S. <ro...@gm...>]

Hi Joe,

Short answer: Blowfish is used in CBC mode. See _writecbc and _readcbc
in Util.cpp (these are called from PWSFile.cpp). IV is m_ipthing, which
is read from the file (called IP in notes.txt). See MakeBlowFish() in
Util.cpp to understand how a key is generated.

Mid-length answer: See
http://www.rsasecurity.com/rsalabs/faq/2-1-4-3.html for a description of
what CBC mode is. The basic idea is to protect against the same
plaintext block producing the same ciphertext block under the same
encryption key.

Longer answer: http://www.rsasecurity.com/rsalabs/faq/sections.html, for
the big picture. Hopefully, this will help understand the rationale
behind how SHA-1 etc. are used in the system.

	enjoy,

		Rony

P.S. - I've updated notes.txt, thanks to comments on minor bugs in the
current implementation.

> -----Original Message-----
> From: pas...@li... 
> [mailto:pas...@li...] On 
> Behalf Of Joe Carter
> Sent: Wednesday, January 28, 2004 13:01
> Cc: pas...@li...
> Subject: Re: [Passwordsafe-devel] Symbian port?
> 
> 
> Thanks for the pointers, I've got these documents now.
> I'm starting to play with BlowfishJ to try and decrypt the 
> current (v2) 
> archives.
> I'm confused about how I use the key in conjunction with the random 8 
> byte block
> and the SHA-1 bit. BlowfishJ gives an option for either ECB 
> or CBC too, with the CBC option taking an extra parameter.
> 
> Sorry if this is really dense (or I should RTFM), but can 
> someone tell me which bits of data go where?
> 
> Data I can see...
> password key
> (from the file format)
> 8 byte random block
> SHA-1 block (how big is this btw?)
> 
> What BlowfishJ wants:
> key
> CBCIV parameter (if I use CBC) - no idea what this is!
> 
> I've tried a simple attempt with ECB but that doesn't appear 
> to work so 
> I obviously
> need to use the random block somehow... Is this the CBC?
> 
> Thanks
> 
> Joe
> 
> 
> Rony Shapiro wrote:
> 
> >Hi Joe,
> >
> >The file format is documented in the files notes.txt and 
> formatV2.txt 
> >in the CVS repository. Let me know if you have troble 
> finding them, and 
> >I'll send you a copy.
> >
> >	Rony
> >  
> >
>