FastHash | smhasher | |
---|---|---|
3 | 30 | |
19 | 1,704 | |
- | - | |
6.7 | 6.7 | |
6 months ago | 12 days ago | |
C# | C++ | |
MIT License | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
FastHash
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The Smallest Hash Table
I've implemented your RecSplit method in my MPHF benchmark library (written in C#). The suite is not yet public, but I do want to say thank you for your fantastic method/code/paper. In my own rabbithole research, I stumbled upon several artifacts of your rabbithole trail. Most notably the stuff on StackOverflow, which helped my own research.
I've releaed a set og fast hash functions[1] to help gain an understanding of speed vs. quality. My biggest takeaway is that most generic hash functions can be specialized for integer inputs[2], which often reduce latency by quite a lot, making MPFH more attractive over simple iteration on small sets, as the overhead of hashing is considerably smaller.
[1] https://github.com/Genbox/FastHash
[2] https://github.com/Genbox/FastHash/blob/master/src/FastHash/...
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The quick and practical “MSI” hash table
It was made (by Sanmayce) to optimize for instruction-level pipelining, and use the fact that modern CPUs have multiple execution ports. But due to those changes, it is not compatible with FNV1a anymore.
The trick of reading in stripes is employed by many of the fastest hashes. It is kinda funny to see how one author prefers a switch case over for loops, where others prefer while loops. The differences can sometimes have a big impact on what optimizations the compiler decides to use.
[1] https://github.com/Genbox/FastHash/blob/master/src/FastHash....
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Ask HN: What Are You Working On? (August 2022)
At the moment I'm working on FastHash[1], a pet project of mine to port a few high-performance non-cryptographic hash functions to C#.
I'm also trying to build FastLinq, a value-by-reference Language Integrated Query (LINQ) optimized for high-performance scenarios. It is kind of a weird mix as LINQ in .NET is known for its high overhead.
Finally, I'm working on an Office setting synchronization application. I heard a podcast with Paul Thurrott complaining about the lack of sync solutions, so I thought I would do one for fun.
[1] https://github.com/Genbox/FastHash
smhasher
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GxHash - A new (extremely) fast and robust hashing algorithm 🚀
The algorithm passes all SMHasher quality tests and uses rounds of AES block cipher internally, so it is quite robust! For comparison XxH3, t1ha0 and many others don't pass SMHasher (while being slower).
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The PolymurHash universal hash function
Confirmed, I tested it. https://github.com/rurban/smhasher
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Show HN: Discohash – simply, quality, fast hash
There's lots of great hash functions out there: some are super fast, like xxhash and highly optimized, others are also super fast umash and based on interesting math ideas from finite fields^1, while maintaining high quality (according to SMHasher). Others are also fast and interesting (tabulation hash, that may sometimes be seemingly universal), one of the main originators of those ideas are Mikkel Thorup^2. Anyway, a couple of years ago I also tried my hand at building hashes and created a few that passed SMHasher (tifuhash ~ a floating point hash, beamsplitter - a seemingly-universal tabulation style hash, and this one discohash - a "more traditional" ARX-based design (addition rotation xor)^3 ).
0: https://github.com/rurban/smhasher/blob/master/xxh3.h
1: https://pvk.ca/Blog/2022/12/29/fixing-hashing-modulo-alpha-e...
2: https://arxiv.org/abs/1505.01523
3: https://eprint.iacr.org/2018/898.pdf https://crypto.polito.it/content/download/480/2850/file/docu...
4: https://en.wikipedia.org/wiki/BLAKE_(hash_function)
Discohash (posted here) is the fastest one I made, it's simple and doesn't rely on any arch-specific optimizations or vector instructions (AVX etc ~ tho I suppose...they could be added? I'm definitely no expert in them, I barely get away with doing the C/C++ implementations!)
The main mixing round function is:
mix(const int A) {
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A Vulnerability in Implementations of SHA-3, Shake, EdDSA
ubsan, asan, valgrind tests are missing. some do offer symbolic verification of the algo, but not the implementations.
See my https://github.com/rurban/smhasher#crypto paragraph, and
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Academic Urban Legends
The spinach story reminds me a lot on the false recommendation of siphash for hash table DDOS prevention. https://github.com/rurban/smhasher#security
The authors came up in their widely cited paper with a proper solution to spread the random hash seed into the inner loop, vastly enhancing its security by avoiding trivial hash collision attacks. But a secure, slow hash function can never prevent from normal hash seed attacks, when the random seed is known somehow. esp. with dynamic languages it's trivial to get the seed externally.
Other trivial countermeasures must be used then, which also don't make hash tables 10x slower, keeping them practical.
- SHA-1 is out. NIST recommends switching to the SHA-2 and SHA-3 groups of hash algorithms as soon as possible, with an official deadline of Dec. 31, 2030.
- Adventures in Advent of Code
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New ScyllaDB Go Driver: Faster Than GoCQL and Its Rust Counterpart
This is the best, most comprehensive hash test suite I know of: https://github.com/rurban/smhasher/
you might want to particularly look into murmur, spooky, and metrohash. I'm not exactly sure of what the tradeoffs involved are, or what your need is, but that site should serve as a good starting point at least.
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What do you typically use for non-cryptographic hash functions?
Here is a good comparison table, as you can see, BLAKE can perform in secure way much faster than crc32, so my original point, - to use non weak hashes unless you really have a reason/requirement not to do so
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What hash function you use for hash maps / hash tables?
smhasher is a great place to testing results for a massive number of hash algorithms.
What are some alternatives?
PicoPico - Pico-8 Player
xxHash - Extremely fast non-cryptographic hash algorithm
reframe - LeapTable 🦘- The fastest way to build, deploy, and manage LLM-powered agents on tabular data (dataframes, SQL tables and Spreadsheets). [Moved to: https://github.com/peterwnjenga/leaptable]
wyhash - The FASTEST QUALITY hash function, random number generators (PRNG) and hash map.
skeleton - A fully featured UI toolkit for Svelte + Tailwind. [Moved to: https://github.com/skeletonlabs/skeleton]
BLAKE3 - the official Rust and C implementations of the BLAKE3 cryptographic hash function
needle - A CLI tool that finds a needle (opening/intro and ending/credits) in a haystack (TV or anime episode).
Hashids.java - Hashids algorithm v1.0.0 implementation in Java
aHash - aHash is a non-cryptographic hashing algorithm that uses the AES hardware instruction
png-decoder - A pure-Rust, no_std compatible PNG decoder
pyroscope-rs - Pyroscope Profiler for Rust. Profile your Rust applications.
rustls - A modern TLS library in Rust