Timeline for What should I use for consequent AES key derivation?
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| Feb 15, 2019 at 8:50 | vote | accept | TheSKDown | ||
| Feb 13, 2019 at 19:10 | answer | added | Maarten Bodewes♦ | timeline score: 3 | |
| Feb 13, 2019 at 18:54 | comment | added | Maarten Bodewes♦ | @e-sushi That one is specific to password based KDF's, but I guess that it is the same for normal KDF's. | |
| Jan 30, 2019 at 7:40 | comment | added | e-sushi | To find an answer your comment question about the difference between hashes and HKDFs, check Q&As like this one. In short: KDFs must produce results that have certain randomness properties, and be very difficult to reverse while rd hashes only need to satisfy the property "difficult to reverse", without those randomness requirements. Hope that helps… | |
| Jan 30, 2019 at 7:37 | history | edited | e-sushi | CC BY-SA 4.0 |
added emphasis to edit so users don't miss it.
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| Jan 30, 2019 at 6:22 | history | edited | TheSKDown | CC BY-SA 4.0 |
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| Jan 30, 2019 at 6:14 | comment | added | forest | The Double Ratchet protocol takes that into account with the symmetric key ratchet. | |
| Jan 30, 2019 at 6:14 | comment | added | TheSKDown | But for a complete double ratchet I need DH key exchange and a KDF. As stated i already have thought about the DH key exchange since my AES keys are based on it. This leaves me with solving the second part (KDF), so what is the difference between a KDF and a hash function such as SHA-256. They seem to me as the same thing? | |
| Jan 30, 2019 at 6:03 | history | edited | TheSKDown | CC BY-SA 4.0 |
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| Jan 30, 2019 at 6:01 | comment | added | forest | That is not enough, no. You would need to use the full Double Ratchet protocol. | |
| Jan 30, 2019 at 6:00 | comment | added | TheSKDown | I will edit the question since it is not clear but yes I am trying to make it retroactive decryption difficult and I was wondering if hashing the old key is enough to "simulate" the ratchet state since the concept is one way function? | |
| Jan 30, 2019 at 5:55 | review | First posts | |||
| Jan 30, 2019 at 6:38 | |||||
| Jan 30, 2019 at 5:53 | comment | added | forest | Is there a reason you don't want to use an IV for the purpose of encrypting multiple messages with one key? Or is this about minimizing the risk of compromise by making retroactive decryption difficult? Try Double Ratchet. | |
| Jan 30, 2019 at 5:52 | history | asked | TheSKDown | CC BY-SA 4.0 |