Talk:Double Ratchet Algorithm

Name of the article
Trevor Perrin has now renamed the ratcheting algorithm as "Double Ratchet", and Moxie Marlinspike has written that Axolotl actually referred to the full messaging protocol (double ratchet + prekeys + 3DH), which has now been renamed as "Signal Protocol". If this article is only about the ratcheting algorithm, I suggest that it be renamed as "Double ratchet". --Dodi 8238 (talk) 13:55, 31 March 2016 (UTC)


 * I went ahead and changed everything from Axolotl to "double ratchet", seeing that this isn't that controversial. --Dodi 8238 (talk) 14:41, 31 March 2016 (UTC)

Axolotl describes the double ratchet construction, not the full protocol. It's possible OWS used it internally that way, but nobody else did because their public documents only talked about the double ratchet part.

Also, there is not even a public statement by Trevor or anyone at OWS that they prefer the term Axolotl ratchet be replaced by double ratchet. In particular, the github reference should be removed because that repository has no public content https://github.com/trevp/double_ratchet

Finally there are actually various double ratchet constructions possible, depending upon your particular goals. — Preceding unsigned comment added by 78.250.123.11 (talk) 07:56, 9 April 2016 (UTC) [edited by 78.250.96.93 21:54, 10 April 2016‎ (UTC)]


 * Here is the GitHub diff in which Trevor Perrin changed the name of the "Axolotl Ratchet" to "Double Ratchet Algorithm" on 30 March 2016. The public content you're referring to is located here, and it isn't used as a reference anywhere in this article. (It is, however, linked to in the External links section.) Could you provide reliable sources that describe the other double ratchet constructions? Then we could expand this article so that it is more general, and not only about this particular example. --Dodi 8238 (talk) 08:18, 9 April 2016 (UTC) [edited 10:23, 9 April 2016 (UTC)]


 * I've now renamed the article as "Double Ratchet Algorithm" because it is mainly about the algorithm that was developed by Perrin and Marlinspike. The term "double ratchet" now redirects here, but that page can be converted into a general article about double ratchet constructions if enough secondary sources are found. --Dodi 8238 (talk) 10:11, 9 April 2016 (UTC)


 * Adding algorithm is definitely better because "double ratchet" alone apparently refers to a wrench. Afaik, any different double ratchets would be OR, so you can ignore them.  — Preceding unsigned comment added by 78.250.96.93 (talk) 22:21, 10 April 2016 (UTC)

What is a ratchet?
Hi, I looked up this article after reading several of the recent news reports about WhatsApp. I'm wondering what the definition of a ratchet actually is? This might be useful information to put into the article (or is it defined elsewhere? I couldn't find it...) for your average layman reader. Thanks, CaptRik (talk) 12:24, 7 April 2016 (UTC)


 * It's an applied cryptography term that mathematical cryptographers have not really formalized, but maybe they'll do so eventually. Just off the cuff : A ratchet is a stateful one-way algorithm for producing a succession of new key material so that even the participants cannot replicate the old key material, given certain cryptographic assumptions and assuming that they honestly destroy the old key material and state.
 * I suspect Diffie-Hellman ratchets were invented in OtR, maybe by Ian Goldberg. Axolotl combines a natural successor to the OtR's Diffie-Hellman ratchet with a kinda weak hash iteration ratchet invented by Silent Circle.  It gives you stronger forward secrecy properties than either one.
 * In fact, a huge advancement here is not so much the ratchet itself as the understanding that the ratchet state should be preserved long-term in between what the users view as sessions. I suspect Silent Circle should be credited with that, as they were interested in email-like applications.
 * At times, Axolotl is credited to both Moxie and Trevor. A priori, I'd suspect that's due to Moxie pushing for that extra long-term forward-secrecy, after understanding why it was valuable from seeing Silent Circle, but who knows.  — Preceding unsigned comment added by 78.250.96.93 (talk) 22:17, 10 April 2016 (UTC)

Ratcheting (cryptography) article requested
I added a request for a Ratcheting (cryptography) article to Requested_articles/Mathematics. Squideshi (talk) 21:20, 30 March 2019 (UTC)