Actualités en direct des projets (non traduites)
Nouvelles en VO
Minecraft@home - Xoroshiro128++ Guessing Order Optimization Project
- Détails
That said, this is a new CPU app! As time goes on, we'll be replacing configuration files for it to further refine the results, so work will be sent out in stages and we'll feel out how much workunits make sense for each stage.
I've included a fairly technical explanation from the primary author of the app, MC, longtime contributor to Minecraft@Home:
The Xoroshiro Guessing Order project aims to uncover exploitable statistical weaknesses in the xoroshiro128++ pseudorandom number generator (PRNG). Recent versions of Minecraft now use xoroshiro128++ for specific aspects of world generation, replacing Java's default PRNG. Unfortunately, this shift creates significant challenges for seedcracking projects, as no efficient algorithm currently exists to reconstruct the internal state of xoroshiro from its outputs.
Our primary goal is to develop a reliable method for recovering the PRNG's 128-bit seed from just two sequential 64-bit outputs. Currently, the most efficient known method (excluding SAT solvers) involves guessing 54 bits of the state, after which the remaining bits can be derived, a process requiring roughly 9 quadrillion attempts on average. Our aim is to significantly reduce this computational requirement.
Xoroshiro128++ belongs to the "xorshift" family of PRNGs, which means its core operations are linear. The internal state can therefore be represented as a binary vector within a 128-dimensional vector space, with state transitions represented as matrix multiplications. However, the primary challenge arises from its use of a non-linear "scrambler" function, which maps the internal state to its output. Due to this scrambler, there is no straightforward one-to-one relationship between the 128-dimensional internal state and the 128-bit output.
Fortunately, the scrambler function is imperfect. Most of the information provided by each output bit is concentrated in a relatively small subset, approximately a dozen dimensions, of the total 128-dimensional state. Even with a partial, lower-dimensional guess of the state, it is frequently possible to determine whether the guess is incorrect based on the known output. If we can identify low-dimensional subsets of the state space that are significantly constrained by the outputs, we can efficiently guess and verify these smaller portions first, rapidly eliminating incorrect possibilities.
Participants in our project analyze these lower-dimensional subsets of the state space, identifying those subsets most constrained by observed outputs. To facilitate this process, we use a large precomputed table that estimates the amount of information (in bits) xoroshiro's output data provides about each subset of state dimensions.
By ultimately identifying an optimal sequence of highly constrained subspaces, we can incrementally guess the state one dimension at a time, discarding incorrect possibilities early on. Achieving this optimal guessing order would produce a highly efficient algorithm capable of recovering the PRNG's internal state within a small number of attempts, significantly advancing future efforts in Minecraft seedcracking and related research.
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Minecraft@home - Loneliest Seed v1.08
- Détails
I know it's been a bit, life gets in the way sometimes. However, I've released v1.08 of the Loneliest Seed project which aims to address the checkpointing issue.
We're experimenting with a CPU project separate from this as well, so stay tuned for that! If the experiments go well on our end we're anticipating launching a CPU app that will aid us in our years-long research into finding methods of reversing PRNG states in the Xoroshiro128++ algorithm.
Best regards,
Minecraft@Home Team
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Yafu - Aliquot sequence 3126816 has terminated!!!
- Détails
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SRBase - base R402 Megaprime / proven
- Détails
The prime 32*402^683113-1 has 1.778.983 digits and entered the T5k PrimePages.
R402 is now proven!
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PrimeGrid - Peter Bergmann's Birthday Challenge
- Détails
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World Community Grid - Research Update from the MCM Team (March 2025)
- Détails
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- ODLK1 - Change of IP address
- Yafu - Aliquot sequence 3211812 has terminated!!!
- Yafu - Aliquot sequence 3264096, 3251448, 3192612, 3255870 have terminated!!!
- Einstein@home - Update on “Einstein@Home: Pulsar Seekers”
- Einstein@home - Update on “Einstein@Home: Pulsar Seekers”
- Yafu - Aliquot sequence 3197960 and 3270576 have terminated!!!