Blocksize versus file size was: Re: twofish keysize
Per Tunedal Casual
pt at radvis.nu
Tue Apr 20 18:45:43 CEST 2004
At 16:26 2004-04-20, C. D. Rok wrote:
>Per Tunedal Casual wrote:
>> BTW I've been told it isn't wise to encrypt files larger than a few MB
>> using a block size of 64 bits.
>I wasn't aware of this; is it cipher dependent od does it apply to
>all block ciphers? Any pointers to additinal info?
It appears to apply to all block ciphers, but it should be "a few HUNDRED
megabytes", according to what I found with Google:
"Blowfish has a 64 bit block size and a key length of anywhere from 32 bits
to 448 bits. ... It should be noted that, like other block cyphers with a
64 bit block, it is risky to encrypt extremely large texts (more than a few
hundred megabytes) with a single key. If more data is to be encrypted a
block cipher with a larger block size should be used."
More information about the Gnupg-users