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2 More number for the questions about SSL overheads....
4 The following numbers were generated on a Pentium pro 200, running Linux.
5 They give an indication of the SSL protocol and encryption overheads.
7 The program that generated them is an unreleased version of ssl/ssltest.c
8 which is the SSLeay ssl protocol testing program. It is a single process that
9 talks both sides of the SSL protocol via a non-blocking memory buffer
10 interface.
12 How do I read this? The protocol and cipher are reasonable obvious.
13 The next number is the number of connections being made. The next is the
14 number of bytes exchanged between the client and server side of the protocol.
15 This is the number of bytes that the client sends to the server, and then
16 the server sends back. Because this is all happening in one process,
17 the data is being encrypted, decrypted, encrypted and then decrypted again.
18 It is a round trip of that many bytes. Because the one process performs
19 both the client and server sides of the protocol and it sends this many bytes
20 each direction, multiply this number by 4 to generate the number
21 of bytes encrypted/decrypted/MACed. The first time value is how many seconds
22 elapsed doing a full SSL handshake, the second is the cost of one
23 full handshake and the rest being session-id reuse.
25 SSLv2 RC4-MD5 1000 x 1 12.83s 0.70s
26 SSLv3 NULL-MD5 1000 x 1 14.35s 1.47s
27 SSLv3 RC4-MD5 1000 x 1 14.46s 1.56s
28 SSLv3 RC4-MD5 1000 x 1 51.93s 1.62s 1024bit RSA
29 SSLv3 RC4-SHA 1000 x 1 14.61s 1.83s
30 SSLv3 DES-CBC-SHA 1000 x 1 14.70s 1.89s
31 SSLv3 DES-CBC3-SHA 1000 x 1 15.16s 2.16s
33 SSLv2 RC4-MD5 1000 x 1024 13.72s 1.27s
34 SSLv3 NULL-MD5 1000 x 1024 14.79s 1.92s
35 SSLv3 RC4-MD5 1000 x 1024 52.58s 2.29s 1024bit RSA
36 SSLv3 RC4-SHA 1000 x 1024 15.39s 2.67s
37 SSLv3 DES-CBC-SHA 1000 x 1024 16.45s 3.55s
38 SSLv3 DES-CBC3-SHA 1000 x 1024 18.21s 5.38s
40 SSLv2 RC4-MD5 1000 x 10240 18.97s 6.52s
41 SSLv3 NULL-MD5 1000 x 10240 17.79s 5.11s
42 SSLv3 RC4-MD5 1000 x 10240 20.25s 7.90s
43 SSLv3 RC4-MD5 1000 x 10240 58.26s 8.08s 1024bit RSA
44 SSLv3 RC4-SHA 1000 x 10240 22.96s 11.44s
45 SSLv3 DES-CBC-SHA 1000 x 10240 30.65s 18.41s
46 SSLv3 DES-CBC3-SHA 1000 x 10240 47.04s 34.53s
48 SSLv2 RC4-MD5 1000 x 102400 70.22s 57.74s
49 SSLv3 NULL-MD5 1000 x 102400 43.73s 31.03s
50 SSLv3 RC4-MD5 1000 x 102400 71.32s 58.83s
51 SSLv3 RC4-MD5 1000 x 102400 109.66s 59.20s 1024bit RSA
52 SSLv3 RC4-SHA 1000 x 102400 95.88s 82.21s
53 SSLv3 DES-CBC-SHA 1000 x 102400 173.22s 160.55s
54 SSLv3 DES-CBC3-SHA 1000 x 102400 336.61s 323.82s
56 What does this all mean? Well for a server, with no session-id reuse, with
57 a transfer size of 10240 bytes, using RC4-MD5 and a 512bit server key,
58 a Pentium pro 200 running Linux can handle the SSLv3 protocol overheads of
59 about 49 connections a second. Reality will be quite different :-).
61 Remember the first number is 1000 full ssl handshakes, the second is
62 1 full and 999 with session-id reuse. The RSA overheads for each exchange
63 would be one public and one private operation, but the protocol/MAC/cipher
64 cost would be quite similar in both the client and server.
66 eric (adding numbers to speculation)
68 --- Appendix ---
69 - The time measured is user time but these number a very rough.
70 - Remember this is the cost of both client and server sides of the protocol.
71 - The TCP/kernel overhead of connection establishment is normally the
72 killer in SSL. Often delays in the TCP protocol will make session-id
73 reuse look slower that new sessions, but this would not be the case on
74 a loaded server.
75 - The TCP round trip latencies, while slowing individual connections,
76 would have minimal impact on throughput.
77 - Instead of sending one 102400 byte buffer, one 8k buffer is sent until
78 - the required number of bytes are processed.
79 - The SSLv3 connections were actually SSLv2 compatible SSLv3 headers.
80 - A 512bit server key was being used except where noted.
81 - No server key verification was being performed on the client side of the
82 protocol. This would slow things down very little.
83 - The library being used is SSLeay 0.8.x.
84 - The normal measuring system was commands of the form
85 time ./ssltest -num 1000 -bytes 102400 -cipher DES-CBC-SHA -reuse
86 This modified version of ssltest should be in the next public release of
87 SSLeay.
89 The general cipher performance number for this platform are
91 SSLeay 0.8.2a 04-Sep-1997
92 built on Fri Sep 5 17:37:05 EST 1997
93 options:bn(64,32) md2(int) rc4(idx,int) des(ptr,risc1,16,long) idea(int) blowfish(ptr2)
94 C flags:gcc -DL_ENDIAN -DTERMIO -O3 -fomit-frame-pointer -m486 -Wall -Wuninitialized
95 The 'numbers' are in 1000s of bytes per second processed.
96 type 8 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes
97 md2 131.02k 368.41k 500.57k 549.21k 566.09k
98 mdc2 535.60k 589.10k 595.88k 595.97k 594.54k
99 md5 1801.53k 9674.77k 17484.03k 21849.43k 23592.96k
100 sha 1261.63k 5533.25k 9285.63k 11187.88k 11913.90k
101 sha1 1103.13k 4782.53k 7933.78k 9472.34k 10070.70k
102 rc4 10722.53k 14443.93k 15215.79k 15299.24k 15219.59k
103 des cbc 3286.57k 3827.73k 3913.39k 3931.82k 3926.70k
104 des ede3 1443.50k 1549.08k 1561.17k 1566.38k 1564.67k
105 idea cbc 2203.64k 2508.16k 2538.33k 2543.62k 2547.71k
106 rc2 cbc 1430.94k 1511.59k 1524.82k 1527.13k 1523.33k
107 blowfish cbc 4716.07k 5965.82k 6190.17k 6243.67k 6234.11k
108 sign verify
109 rsa 512 bits 0.0100s 0.0011s
110 rsa 1024 bits 0.0451s 0.0012s
111 rsa 2048 bits 0.2605s 0.0086s
112 rsa 4096 bits 1.6883s 0.0302s