Passwords - A Bad Mnemonic System: Difference between revisions
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Guess we have a pin number: 3401, this number is coded in the following scheme with a word, let's say ''c-r-a-p''. |
Guess we have a pin number: 3401, this number is coded in the following scheme with a word, let's say ''c-r-a-p'' supposed to be an easy reminder. |
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<pre> |
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___0______1______2______3______4______5______6______7______8______9__ |
___0______1______2______3______4______5______6______7______8______9__ |
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| | | | | | | | | | | |
| | | | | | | | | | | |
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| Line 14: | Line 14: | ||
| | P | | | | | | | | | |
| | P | | | | | | | | | |
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|______|______|______|______|______|______|______|______|______|______| |
|______|______|______|______|______|______|______|______|______|______| |
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</pre> |
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---- |
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In the next step all the blank fields are filled up with random characters. |
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<pre> |
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___0______1______2______3______4______5______6______7______8______9__ |
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| | | | | | | | | | | |
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| F | I | W | C | K | N | O | E | S | Y | |
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|______|______|______|______|______|______|______|______|______|______| |
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| | | | | | | | | | | |
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| H | F | V | O | R | G | T | D | F | U | |
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|______|______|______|______|______|______|______|______|______|______| |
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| | | | | | | | | | | |
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| A | G | E | L | P | H | M | D | A | C | |
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|______|______|______|______|______|______|______|______|______|______| |
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| | | | | | | | | | | |
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| T | P | F | O | M | W | Z | K | S | K | |
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|______|______|______|______|______|______|______|______|______|______| |
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</pre> |
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'''Conclusion:''' This is really a bad mnemonic system for bank PINs. The odds sank from 1 in 3000 to 1 in 8 (if three attempts are allowed), because there are only about 20-30 words in the whole scheme. |
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Some banks allow customers to use their own pins and it is believed that about a third uses a birthday. |
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[[Passwords - Design Errors And Operational Issues|Back (Design Errors)]] | [[Passwords - Table of Contents|Table of Contents]] | [[Passwords - System Issues|Next (System Issues)]] |
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Latest revision as of 20:50, 8 November 2004
Guess we have a pin number: 3401, this number is coded in the following scheme with a word, let's say c-r-a-p supposed to be an easy reminder.
___0______1______2______3______4______5______6______7______8______9__ | | | | | | | | | | | | | | | C | | | | | | | |______|______|______|______|______|______|______|______|______|______| | | | | | | | | | | | | | | | | R | | | | | | |______|______|______|______|______|______|______|______|______|______| | | | | | | | | | | | | A | | | | | | | | | | |______|______|______|______|______|______|______|______|______|______| | | | | | | | | | | | | | P | | | | | | | | | |______|______|______|______|______|______|______|______|______|______|
In the next step all the blank fields are filled up with random characters.
___0______1______2______3______4______5______6______7______8______9__ | | | | | | | | | | | | F | I | W | C | K | N | O | E | S | Y | |______|______|______|______|______|______|______|______|______|______| | | | | | | | | | | | | H | F | V | O | R | G | T | D | F | U | |______|______|______|______|______|______|______|______|______|______| | | | | | | | | | | | | A | G | E | L | P | H | M | D | A | C | |______|______|______|______|______|______|______|______|______|______| | | | | | | | | | | | | T | P | F | O | M | W | Z | K | S | K | |______|______|______|______|______|______|______|______|______|______|
Conclusion: This is really a bad mnemonic system for bank PINs. The odds sank from 1 in 3000 to 1 in 8 (if three attempts are allowed), because there are only about 20-30 words in the whole scheme.
Some banks allow customers to use their own pins and it is believed that about a third uses a birthday.
Back (Design Errors) | Table of Contents | Next (System Issues)