This document shows the approximate amount of time required for a computer or a cluster of computers to guess various passwords. The figures shown are approximate and are the maximum time required to guess each password using a simple brute force "key-search" attack, it may (and probably will) be possible to guess correctly without trying all the combinations shown using other methods of attack or by having a "lucky guess".
See the bottom of the page for details about the classes of attack.
10 Characters
Just numbers. As you can see choosing a password from such a small range of characters is a bad idea.
| Numerals | 0123456789 | ||||||
|---|---|---|---|---|---|---|---|
| Password | Class of Attack | ||||||
| Length | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| 2 | 100 | Instant | Instant | Instant | Instant | Instant | Instant |
| 3 | 1000 | Instant | Instant | Instant | Instant | Instant | Instant |
| 4 | 10,000 | Instant | Instant | Instant | Instant | Instant | Instant |
| 5 | 100,000 | 10 Secs | Instant | Instant | Instant | Instant | Instant |
| 6 | 1 Million | 1½ Mins | 10 Seconds | Instant | Instant | Instant | Instant |
| 7 | 10 Million | 17 Mins | 1½ Mins | 1½ Mins | Instant | Instant | Instant |
| 8 | 100 Million | 2¾ Hours | 17 Mins | 1½ Mins | 10 Seconds | Instant | Instant |
| 9 | 1000 Million | 28 Hours | 2¾ Hours | 17 Mins | 1½ Mins | 10 Seconds | Instant |
26 Characters
The full alphabet, either upper or lower case (not both in this case).
| Upper Case Alpha | ABCDEFGHIJKLMNOPQRSTUVWXYZ | ||||||
|---|---|---|---|---|---|---|---|
| Lower Case Alpha | abcdefghijklmnopqrstuvwxyz | ||||||
| Password | Class of Attack | ||||||
| Length | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| 2 | 676 | Instant | Instant | Instant | Instant | Instant | Instant |
| 3 | 17,576 | <> | Instant | Instant | Instant | Instant | Instant |
| 4 | 456,976 | 46 Secs | 5 Secs | Instant | Instant | Instant | Instant |
| 5 | 11.8 Million | 20 Mins | 2 Mins | 12 Secs | Instant | Instant | Instant |
| 6 | 308.9 Million | 8½ Hours | 51½ Mins | 5 Mins | 30 Secs | 3 Secs | Instant |
| 7 | 8 Billion | 9 Days | 22 Hours | 2¼ Hours | 13 Mins | 1¼ Mins | 8 Secs |
| 8 | 200 Billion | 242 Days | 24 Days | 2½ Days | 348 Mins | 35 Mins | 3½ Mins |
| 9 | 5.4 Trillion | 17 Years | 21 Months | 63 Days | 6¼ Days | 15 Hours | 1½ Hours |
| 10 | 141 Trillion | 447 Years | 45 Years | 4½ Years | 163 Days | 16 Days | 39¼ Hours |
| 12 | 95 Quadrillion | 302,603 Years | 30,260 Years | 3,026 Years | 302 Years | 30 Years | 3 Years |
| 15 | 1.6 Sextillion | 53 Trillion years | 532 Million years | 53 Million years | 5 Million years | 531,855 Years | 53,185 Years |
| 20 | 19.9 Octillion | 63 Quadrillion years | 6.3 Quadrillion years | 631 Trillion years | 63.1 Trillion years | 6.3 Trillion years | 631 Billion years |
36 Characters
The full alphabet, either upper or lower case (not both in this case) plus numbers.
| Upper Case Alpha | ABCDEFGHIJKLMNOPQRSTUVWXYZ | ||||||
|---|---|---|---|---|---|---|---|
| Lower Case Alpha | abcdefghijklmnopqrstuvwxyz | ||||||
| Numerals | 0123456789 | ||||||
| Password | Class of Attack | ||||||
| Length | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| 2 | 1,296 | Instant | Instant | Instant | Instant | Instant | Instant |
| 3 | 46,656 | 4 Secs | Instant | Instant | Instant | Instant | Instant |
| 4 | 1.6 million | ||||||
| 5 | 60.4 million | ||||||
52 Characters
This time we're trying the full alphabet but using a mixture of upper and lower case letters, that effectively doubles the number of combinations when compared with just using a single case.
| Mixed Alpha | AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz | ||||||
|---|---|---|---|---|---|---|---|
| Password | Class of Attack | ||||||
| Length | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| 2 | 2,704 | Instant | Instant | Instant | Instant | Instant | Instant |
| 3 | 140,608 | 14 Secs | <> | Instant | Instant | Instant | Instant |
| 4 | 7.3 Million | 12½ Mins | 1¼ Mins | 8 Secs | Instant | Instant | Instant |
| 5 | 380 Million | 10½ Hours | 1 Hour | 6 Minutes | 38 Secs | 4 Secs | Instant |
| 6 | 19 Billion | 23 Days | 2¼ Days | 5½ Hours | 33 Mins | 3¼ Mins | 19 Secs |
| 7 | 1 Trillion | 3¼ Years | 119 Days | 12 Days | 28½ Hours | 3 Hours | 17 Mins |
| 8 | 53 Trillion | 169½ Years | 17 Years | 1½ Years | 62 Days | 6 Days | 15 Hours |
| 9 | 2.7 Quadrillion | 8,815 Years | 881 Years | 88 Years | 9 Years | 322 Days | 32 Days |
62 Characters
Mixed upper and lower case alphabetic characters plus numbers.
| Mixed Alpha and Numerals | 0123456789AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz | ||||||
|---|---|---|---|---|---|---|---|
| Password | Class of Attack | ||||||
| Length | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| 2 | 3,844 | Instant | Instant | Instant | Instant | Instant | Instant |
| 3 | 238,328 | 23 Secs | <> | Instant | Instant | Instant | Instant |
| 4 | 15 Million | 24½ Mins | 2½ Mins | 15 Secs | <> | Instant | Instant |
| 5 | 916 Million | 1 Day | 2½ Hours | 15¼ Mins | 1½ Mins | 9 Secs | Instant |
| 6 | 57 Billion | 66 Days | 6½ Days | 16 Hours | 1½ Hours | 9½ Mins | 56 Secs |
| 7 | 3.5 Trillion | 11 Years | 1 Year | 41 Days | 4 Days | 10 Hours | 58 Mins |
| 8 | 218 Trillion | 692 Years | 69¼ Years | 7 Years | 253 Days | 25¼ Days | 60½ Hours |
96 Characters
Mixed upper and lower case alphabet plus numbers and common symbols.
| Mixed Alpha, Numerals & Symbols | 0123456789AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz | ||||||
|---|---|---|---|---|---|---|---|
| Password | Class of Attack | ||||||
| Length | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| 2 | 9,216 | Instant | Instant | Instant | Instant | Instant | Instant |
| 3 | 884,736 | 88½ Secs | 9 Secs | Instant | Instant | Instant | Instant |
| 4 | 85 Million | 2¼ Hours | 14 Mins | 1½ Mins | 8½ Secs | Instant | Instant |
| 5 | 8 Billion | 9½ Days | 22½ Hours | 2¼ Hours | 13½ Mins | 1¼ Mins | 8 Secs |
| 6 | 782 Billion | 2½ Years | 90 Days | 9 Days | 22 Hours | 2 Hours | 13 Mins |
| 7 | 75 Trillion | 238 Years | 24 Years | 2½ Years | 87 Days | 8½ Days | 20 Hours |
| 8 | 7.2 Quadrillion | 22,875 Years | 2,287 Years | 229 Years | 23 Years | 2¼ Years | 83½ Days |
Examples
These are just a couple of examples to show the resilience of certain types of password, using the information in the tables above you will be able to make your own examples.
| Sample Passwords | Class of Attack | ||||||
|---|---|---|---|---|---|---|---|
| Pwd | Combinations | Class A | Class B | Class C | Class D | Class E | Class F |
| darren | 308.9 Million | 8½ Hours | 51½ Mins | 5 Mins | 30 Secs | 3 Secs | Instant |
| Land3rz | 3.5 Trillion | 11 Years | 1 Year | 41 Days | 4 Days | 10 Hours | 58 Mins |
| B33r&Mug | 7.2 Quadrillion | 22,875 Years | 2,287 Years | 229 Years | 23 Years | 2¼ Years | 83½ Days |
Classes of Attack
These are just some example speeds, I'd be interested to hear from people with more information about the speed taken to crack various types of passwords with various hardware.
A. 10,000 Passwords/sec
Typical for recovery of Microsoft Office passwords on a Pentium 100
B. 100,000 Passwords/sec
Typical for recovery of Windows Password Cache (.PWL Files) passwords on a Pentium 100
C. 1,000,000 Passwords/sec
Typical for recovery of ZIP or ARJ passwords on a Pentium 100
D. 10,000,000 Passwords/sec
Fast PC, Dual Processor PC.
E. 100,000,000 Passwords/sec
Workstation, or multiple PC's working together.
F. 1,000,000,000 Passwords/sec
Typical for medium to large scale distributed computing, Supercomputers.
Distributed.net's Project Bovine RC5-64 possibly the fastest computer on earth has recently reached a speed of 76.1 Billion passwords per second!