Talk:Fortuna (PRNG)

Cryptography: Computer science High‑importance

	This article is within the scope of WikiProject Cryptography, a collaborative effort to improve the coverage of Cryptography on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.CryptographyWikipedia:WikiProject CryptographyTemplate:WikiProject CryptographyCryptography
High	This article has been rated as High-importance on the importance scale.
	This article is supported by WikiProject Computer science (assessed as High-importance).

Computing: Software / CompSci / Security Low‑importance

This article is within the scope of WikiProject Computing, a collaborative effort to improve the coverage of computers, computing, and information technology on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.ComputingWikipedia:WikiProject ComputingTemplate:WikiProject ComputingComputing

Low

This article has been rated as Low-importance on the project's importance scale.

This article is supported by WikiProject Software (assessed as Low-importance).

This article is supported by WikiProject Computer science (assessed as Mid-importance).

This article is supported by WikiProject Computer Security (assessed as Top-importance).

Things you can help WikiProject Computer science with:

Here are some tasks awaiting attention:

Article requests :
- Requested articles/Applied arts and sciences/Computer science, computing, and Internet
Cleanup :
- Computer science articles needing attention
- Computer science articles needing expert attention
Copyedit :
- Computing
Expand :
- Computer science
Infobox :
- Computer science articles without infoboxes
Maintain :
- Timeline of computing 2020–present
Photo :
- Find pictures for the biographies of computer scientists (see List of computer scientists)
- Computing articles needing images
Stubs :
- Computer science stubs
Unreferenced :
- WikiProject Computer science/Unreferenced BLPs
Project-related :
- Tag all relevant articles in Category:Computer science and sub-categories with {{WikiProject Computer science}}

Repeated blocks

I don't understand the flaw about repeated blocks created in counter mode. (Well sure, there will be repeated blocks after 2^128 blocks, but that's a silly huge number.)18.209.1.147 08:26, 29 December 2006 (UTC)[reply]

That's because it's wrong. The original version of the article said "repeated blocks would never be generated" or something along those lines; someone changed it to "would be generated", I fixed it, and later on someone broke it again. I'm about to clarify that bit of the article in the hope of making it less likely that well-intentioned people will break it. Gareth McCaughan 17:37, 29 December 2006 (UTC)[reply]

Size of entropy pools

How big is each entropy pool? Cmcqueen1975 (talk) 03:47, 8 December 2010 (UTC)[reply]

Unbounded; usually implemented with some sort of cryptographic hash. The FS&K Chapter suggests SHA_d-256(), although I don't know of any reason plain SHA-256 or any SHA-3 finalist (in 256-bit or greater mode) would not suffice. KMeyer (talk) 00:27, 24 May 2019 (UTC)[reply]

What about the Pseudo part?

Can someone please clarify what needs to be controlled in order for this algrorithm to produce a repeatable random sequence? Do you have to feed the pools with the same data on each run?199.34.4.20 (talk) 22:14, 4 October 2016 (UTC)[reply]

You have to control the "entropy" sources and timing, and the timing/size of reads, from some known starting state (current key, counter and pools value(s)). Fortuna will reseed from the pools every 100 ms, if pool 0 has gathered sufficient bytes of entropy input over that interval, on demand (if a read is made). It will also rekey (key erasure / forward secrecy) on every read operation, or every 1MB for large read operations. If those are all controlled, the same output is produced. KMeyer (talk) 00:34, 24 May 2019 (UTC)[reply]

Contradiction

These 2 sections have 2 sentences that contradicts the other if there are over 10 data requests a second (unless there is a limit on the amount of requests per second):

Seeding

The key is also changed after every data request (however small), so that a future key compromise doesn't endanger previous generator outputs.

Generator

Fortuna uses 32 pools, and restricts reseeding to happen at most 10 times per second. Aera23 (talk) 01:33, 24 July 2024 (UTC)[reply]