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diff --git a/src/ext/equix/README.md b/src/ext/equix/README.md new file mode 100644 index 0000000000..d3e8c93125 --- /dev/null +++ b/src/ext/equix/README.md @@ -0,0 +1,77 @@ +# Equi-X + +Equi-X is a CPU-friendly [client puzzle](https://en.wikipedia.org/wiki/Client_Puzzle_Protocol) +with fast verification and small solution size (16 bytes). It is based on Equihash(60,3) with +two major changes: + +1. Blake2b hash function is replaced with [HashX](https://github.com/tevador/hashx). +2. XOR is replaced with modular addition. + +An Equi-X solution for nonce `X` is a set of eight 16-bit indices <code>i<sub>0</sub>, ..., i<sub>7</sub></code> such that: + +<code>H<sub>X</sub>(i<sub>0</sub>) + H<sub>X</sub>(i<sub>1</sub>) + H<sub>X</sub>(i<sub>2</sub>) + H<sub>X</sub>(i<sub>3</sub>) + H<sub>X</sub>(i<sub>4</sub>) + H<sub>X</sub>(i<sub>5</sub>) + H<sub>X</sub>(i<sub>6</sub>) + H<sub>X</sub>(i<sub>7</sub>) = 0 (mod 2<sup>60</sup>)</code> + +where <code>H<sub>X</sub></code> is a HashX function generated for nonce `X`. Equi-X is therefore a variant of the [subset sum problem](https://en.wikipedia.org/wiki/Subset_sum_problem). Each nonce value provides 2 solutions on average. + +Equi-X also has additional requirements that prove that the solution was found using the Wagner's algorithm. See the [Equihash paper](https://eprint.iacr.org/2015/946.pdf) for details. + +### Example solution + +``` +H(0x6c31) = 0xcfa5375c0a7f5d7 \ + (+) = 0xa73d9777f110000 \ +H(0x8803) = 0xd798601be690a29 / | + (+) = 0xefdaadb00000000 \ +H(0x80c2) = 0xcabd8974bbee8d5 \ | | + (+) = 0x489d16380ef0000 / | +H(0xa1db) = 0x7ddf8cc3530172b / | + (+) = 0 +H(0x6592) = 0x348a96fd685dcba \ | + (+) = 0x357120e8ffb8000 \ | +H(0x76b7) = 0x00e689eb975a346 / | | + (+) = 0x102552500000000 / +H(0x74a6) = 0xacccc4ad2d06bcd \ | + (+) = 0xdab431670048000 / +H(0xe259) = 0x2de76cb9d341433 / +``` + +## Performance + +|Algorithm |n |k |memory |solution size|verification <sup>1</sup>|CPU perf. <sup>2</sup>|GPU perf. <sup>3</sup>| +|----------|---|---|-------|-------------|------------|-----------|----------| +|**Equi-X**|60 |3 |1.8 MiB|16 bytes |~50 μs |2400 Sol/s| ? | +|Zcash |200|9 |144 MiB|1344 bytes |>150 μs |30 Sol/s |~400 Sol/s <sup>4</sup>| +|BTG |144|5 |2.5 GiB|100 bytes |~10 μs |1 Sol/s |~45 Sol/s <sup>5</sup>| + +1. Using AMD Ryzen 1700 with 1 thread. +1. Using AMD Ryzen 1700 with 16 threads. +1. Using NVIDIA GTX 1660 Ti. +1. Estimated from http://www.zcashbenchmarks.info/ (GTX 1070) +1. Estimated from https://miniz.ch/features/ + +## Build + +``` +git clone --recursive https://github.com/tevador/equix.git +cd equix +mkdir build +cd build +cmake .. +make +``` +``` +./equix-tests +./equix-bench --help +``` + +## Design notes + +See [devlog.md](devlog.md) + +## Donations + +You can support the development of Equi-X by sending XMR to this address: + +``` +85GkKXSD8EQ22EMC2ZKF64S6L6Lcm8Gr23VbAKB1zg6FUW81sUEmrvvRPoM3GCpUZSC9azCLdeityW2N3CVsV4CAC3p1evV +```
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