[Bug 54180] Re: [rfe] sshd ought to support 'none' cipher

[Daniel J Blueman]

Problem is that SSH performance is still 10-30x slower with encryption.
On a 3.6GHz Intel Penryn with plenty of memory bandwidth [1], we see
around 67MB/s - 109MB/s [2]. Moving from 'secret' aes-128-cbc (the
default) to 'top-secret' aes-256-cbc (the most secure) is almost free.

Moving from MD5 hashing reduces performance too [3].

--- [1]

$ sudo hdparm -T /dev/sda
/dev/sda:
 Timing cached reads:   18030 MB in  2.00 seconds = 9026.75 MB/sec

--- [2]

$ for c in 3des-cbc aes128-cbc aes192-cbc aes256-cbc aes128-ctr
aes192-ctr aes256-ctr arcfour128 arcfour256 arcfour blowfish-cbc
cast128-cbc; do echo using cipher $c; ssh -c $c localhost dd
if=/dev/zero bs=32k count=10000 >/dev/null; done

3des-cbc		22.6 MB/s
aes128-cbc	63.8 MB/s
aes192-cbc	67.6 MB/s
aes256-cbc	67.4 MB/s
aes128-ctr	74.9 MB/s
aes192-ctr	73.6 MB/s
aes256-ctr	73.3 MB/s
arcfour128	109 MB/s
arcfour256	108 MB/s
arcfour		107 MB/s
blowfish-cbc	75.0 MB/s
cast128-cbc	62.0 MB/s

--- [3]

$ for m in hmac-md5 hmac-sha1 umac-64 hmac-ripemd160; do echo using
digest $m; ssh -c arcfour128 -m $m localhost dd if=/dev/zero bs=32k
count=10000 >/dev/null; done

hmac-md5	108 MB/s
hmac-sha1	97.9 MB/s
hmac-ripemd160	83.0 MB/s

-- 
[rfe] sshd ought to support 'none' cipher
https://bugs.launchpad.net/bugs/54180
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