CITS3002 Computer Networks  
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(Old) performance of the basic building blocks

Message digest algorithms (on 233MHz Pentium-II, but speed scales linearly):

Algorithms Calculation (KB/sec)
MD5 36,250
SHA-1 20,428

Symmetric key algorithms (233MHz Pentium-II):

Algorithms Setup (ms) Encryption (KB/sec) Decryption (KB/sec)
DES (56 bit) 6.3 4,386 4,557
Triple-DES (112 bit) 22 1,596 1,620
RC4 (128 bits) 29.8 27,325 28,132
RC5 (128 bit) 352 4,576 4,691

Asymmetric key algorithms (233MHz Pentium-II):

  512 bits (KB/s) 1024 bits (KB/s) 2048 bits (KB/s)
RSA encryption 10.5 4.23 0.436
RSA decryption 5.28 2.87 1.4

The command-line openssl program provides speeds on contemporary machines: 

    linux>  openssl
    OpenSSL> speed md5
    To get the most accurate results, try to run this
    program when this computer is idle.
    Doing md5 for 3s on 16 size blocks: 1722968 md5's in 2.80s
    Doing md5 for 3s on 64 size blocks: 1469874 md5's in 2.80s
     ....
    type    16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
    md5     9833.40k    33603.65k    92756.49k   167532.74k   217651.97k

For large amounts of data, we first encrypt the data with a symmetric algorithm and then encrypt the symmetric key with an asymmetric algorithm.
Hybrid protocols are used in most current cryptographic architectures, such as SSL.

CITS3002 Computer Networks, Lecture 12, Cryptography's role in networking, p18, 22nd May 2024.