Security Basics mailing list archives
Re: splited file encrypted with blowfish secure?
From: "Shreyas Zare" <shreyas () technitium com>
Date: Wed, 5 Nov 2008 11:36:04 +0530
Hi, No. That would be same if the entire file was intact. When two blocks of plain text are same then it would be problem. Also, 16MB in here is the file split size and not the block size. Block size depends upon the algorithm used and also its key bit length. If two blocks of plain text in the file are same then in the same file the cipher text would repeat. So splitting the file wont have any special impact. Regards, On Wed, Nov 5, 2008 at 12:10 AM, Ansgar Wiechers <bugtraq () planetcobalt net> wrote:
On 2008-11-04 Andre Pawlowski wrote:I have a question about the security of my encryption. I have written a program in php which splits a file in small parts, encrypts each of them with blowfish and put it together. It uses the same key for every encryption of the parts. The reason I do it like this is that php is only allowed to use 16MB of memory space and so it cannot encrypt or decrypt large files. Here is my question. Is it less secure when I encrypt a file not as one big file? I mean, is it easier for someone to get the key or plain data of a file if he has 100 parts encrypted with the same key in comparison with only having one big file?Yes. http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation#Electronic_codebook_.28ECB.29 Regards Ansgar Wiechers -- "All vulnerabilities deserve a public fear period prior to patches becoming available." --Jason Coombs on Bugtraq
-- ("There are only 10 kinds of people in this world: those who know binary and those who don't.") Shreyas Zare Co-Founder, Technitium eMail: shreyas () technitium com ..::< The Technitium Team >::.. Visit us at www.technitium.com Contact us at theteam () technitium com Join Sci-Tech News group and get the latest science & technology news in your inbox. Visit http://tech.groups.yahoo.com/group/sci-tech-news to join.
Current thread:
- splited file encrypted with blowfish secure? Andre Pawlowski (Nov 04)
- Re: splited file encrypted with blowfish secure? Ansgar Wiechers (Nov 04)
- Re: splited file encrypted with blowfish secure? Shreyas Zare (Nov 05)
- Re: splited file encrypted with blowfish secure? Roscoe (Nov 10)
- <Possible follow-ups>
- Re: splited file encrypted with blowfish secure? Andre Pawlowski (Nov 12)
- Re: splited file encrypted with blowfish secure? Sam Stelfox (Nov 24)
- Re: splited file encrypted with blowfish secure? Ansgar Wiechers (Nov 04)