Timeline for Can you explain “weak keys” for DES?
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| Dec 5, 2022 at 15:09 | comment | added | Ilmari Karonen | @tonythestark: Utimately, it comes the PC-1 permutation in the DES specification, which I linked to in my answer above. (Note that the linked Wikipedia page just gives the permutation as a table with no explanation, but it actually has a very simple structure: horizontally adjacent entries in the table always differ by 8 and vertically adjacent ones by 9 for the left half and 7 for the right half. Now consider that a byte has 8 bits…) | |
| Dec 5, 2022 at 11:35 | comment | added | tonythestark | and how do we come up with the fact that these keys have KL, KR that repeat with a period of 2 ? Where does this comes from ? | |
| Oct 22, 2017 at 10:39 | comment | added | gen | "In particular, because DES is a Feistel cipher, and therefore each DES round is its own inverse (except for the swapping of the half-blocks),", does this mean that DES(LR) = RL for a weak key where the plaintext is split into two halves L and R? | |
| Mar 17, 2017 at 10:46 | history | edited | CommunityBot |
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| Nov 9, 2016 at 14:35 | history | edited | Ilmari Karonen | CC BY-SA 3.0 |
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| Nov 9, 2016 at 12:08 | comment | added | Basile Bruneau | @Ilmari Karonen: thank you for your clear explanation! However, it doesn't prove that these are the only weak keys, does it? It proves well that these four keys are weak, but I don't see why they should be the only weak keys. Thank you! | |
| Dec 9, 2013 at 0:01 | vote | accept | Bush | ||
| Dec 8, 2013 at 23:58 | history | edited | Ilmari Karonen | CC BY-SA 3.0 |
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| Dec 8, 2013 at 23:41 | history | answered | Ilmari Karonen | CC BY-SA 3.0 |