Encryption speeds-- which is faster, OFB or CFB?

Google · 2010-12-10 20:16:48

I have been trying to figure this out. I have found conflicting results. In some cases they say CFB is faster and in other resources I have found that OFB can save speed using a few techniques. Which would be faster? Any way to figure this out?

cactus · 2010-12-11 00:08:52

http://en.wikipedia.org/wiki/Cipher_mod … _.28CFB.29
http://en.wikipedia.org/wiki/Cipher_mod … _.28OFB.29

Presumably, they are both _really close_ to the same speed, and would be limited by the block cipher itself (I see this said often, but sometimes see it said that OFB is faster. So not entirely sure.)

I generally use CTR for my ssh connections, as it is parallelizable.

host * 
  ciphers aes128-ctr,aes192-ctr,aes256-ctr

I prefer aes-128 based on this: http://www.schneier.com/blog/archives/2 … w_aes.html

might also be helpful: http://stackoverflow.com/questions/1220 … tr-ocb-cfb

Last edited by cactus (2010-12-11 00:11:40)

cactus · 2010-12-11 00:20:01

Also this is a _great_ presentation.
http://www.bsdcan.org/2010/schedule/events/183.en.html

Google · 2010-12-11 13:31:42

Thanks, it seems really hard to figure out which is faster. I see conflicting statements quite often. I am enjoying the links though, lots of nice information.

Arch Linux

#1 2010-12-10 20:16:48

Encryption speeds-- which is faster, OFB or CFB?

#2 2010-12-11 00:08:52

Re: Encryption speeds-- which is faster, OFB or CFB?

#3 2010-12-11 00:20:01

Re: Encryption speeds-- which is faster, OFB or CFB?

#4 2010-12-11 13:31:42

Re: Encryption speeds-- which is faster, OFB or CFB?

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