Re: [ANN] Lua 5.2.0 (work5) now available
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- Subject: Re: [ANN] Lua 5.2.0 (work5) now available
- From: pj@...
- Date: Sat, 6 Nov 2010 13:29:43 +1000
Joseph Stewart wrote:
> but what can't you do with 32-bit values that you need to do?
I wrote:
> Strong encryption ?
> In block cyphers, you need lots of XOR ops, and block sizes of
> 32 bits are inherently vulnerable but 64 bits are very tough...
Rob Kendrick wrote:
> It's difficult to see how simply doubling the number of bits
> you process at once removes an inherent vulnerability.
See: http://en.citizendium.org/wiki/Code_book_attack
DES and the generation of ciphers that followed it all used a 64-bit
block size. To completely break a single key, an attacker would need
a code book with 2^64 entries. Even to weaken it significantly takes
a code book with 2^32 entries with the same key, 32 gigabytes of data.
With any sensible re-keying policy, a code book attack is not a threat.
More recent ciphers such as AES use a 128-bit block size,
which makes code book attacks utterly impractical.
The algorithms we use down here at the consumer-level are still
64-bit-block-size, see e.g.:
http://www.kremlinencrypt.com/algorithms.htm
Michal Kottman wrote:
> encryption in pure Lua - of course you CAN do it, but IMHO it is better
> to "leave it to the experts" and use existing cryptography libraries,
> like OpenSSL (which even come with cryptography hardware support).
> ... luacrypto (http://github.com/mkottman/luacrypto - my fork ...)
Cryptography is fun...
Regards, Peter Billam
http://www.pjb.com.au pj@pjb.com.au (03) 6278 9410
"Was der Meister nicht kann, vermöcht es der Knabe, hätt er
ihm immer gehorcht?" Siegfried to Mime, from Act 1 Scene 2