applied cryptography - protocols, algorithms, and source code in c

All told more than 60000 separate words were

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Unformatted text preview: ferential between an exhaustive search for 8-byte keys and an exhaustive search of 4-, 5-, 6-, 7-, and 8-byte keys. All specialized brute-force hardware and parallel implementations will work here. Testing a million keys per second (either with one machine or with multiple machines in parallel), it is feasible to crack lowercase-letter and lowercase-letter-and-number keys up to 8 bytes long, alphanumeric-character keys up to 7 bytes long, printable character and ASCII-character keys up to 6 bytes long, and 8-bit-ASCII-character keys up to 5 bytes long. Table 8.1 Number of Possible Keys of Various Keyspaces 4-Byte 5-Byte 6-Byte 3.1*108 2.2*109 5.7*1010 7.4*1011 4.4*1012 2.8*1014 7-Byte 8.0*109 7.8*1010 3.5*1012 7.0*1013 5.6*1014 7.2*1016 8-Byte 2.1*1011 2.8*1012 2.2*1014 6.6*1015 7.2*1016 1.8*1019 Lowercase letters (26): 460,000 1.2*107 Lowercase letters and digits (36): 1,700,000 6.0*107 Alphanumeric characters (62): 1.5*107 9.2*108 Printable characters (95): 8.1*107 7.7*109 ASCII characters (128): 2.7*108 3.4*1010 8-bit ASCII characters (256): 4.3*109 1.1*1012 Table 8.2 Exhaustive Search of Various Keyspaces (assume one million attempts per second) 4-Byte Lowercase letters (26): Lowercase letters and digits (36): Alphanumeric characters (62): Printable characters (95): ASCII characters (128): 8-bit ASCII characters (256): 5-Byte 6-Byte 7-Byte 8-Byte .5 seconds 12 seconds 5 minutes 2.2 hours 2.4 days 1.7 1 minute 36 minutes 22 hours 33 days seconds 15 seconds 15 minutes 16 hours 41 days 6.9 years 1.4 minutes 4.5 minutes 1.2 hours 2.1 hours 8.5 days 9.5 hours 51 days 13 days 8.9 years 2.2 years 210 years 18 years 2300 years 2300 years 580,000 years Previous Table of Contents Next Products | Contact Us | About Us | Privacy | Ad Info | Home Use of this site is subject to certain Terms & Conditions, Copyright © 1996-2000 EarthWeb Inc. All rights reserved. Reproduction whole or in part in any form or medium without express written permission of EarthWeb is prohibited. Read EarthWeb's privacy statement. To access the contents, click the chap...
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