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10x faster than crypto/rand. Uses securely allocated memory. Forked from https://gitlab.com/NebulousLabs/fastrand
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README.md

fastrand

Cirrus CI GoDoc Go Report Card

go get github.com/awnumar/fastrand

fastrand implements a cryptographically secure pseudorandom number generator. The generator is seeded using the system's default entropy source, and thereafter produces random values via repeated hashing. As a result, fastrand can generate randomness much faster than crypto/rand, and generation cannot fail beyond a potential panic during init().

fastrand was forked from gitlab.com/NebulousLabs/fastrand. This version of the package uses securely allocated memory provided by github.com/awnumar/memguard.

fastrand also scales better than crypto/rand and math/rand when called in parallel. In fact, fastrand can even outperform math/rand when using enough threads.

Benchmarks

// 32 byte reads
BenchmarkRead32                     	10000000	       175 ns/op	 181.86 MB/s
BenchmarkReadCrypto32               	  500000	      2733 ns/op	  11.71 MB/s

// 512 kb reads
BenchmarkRead512kb                   	    1000	   1336217 ns/op	 383.17 MB/s
BenchmarkReadCrypto512kb             	      50	  33423693 ns/op	  15.32 MB/s

// 32 byte reads using 4 threads
BenchmarkRead4Threads32               	 3000000	       392 ns/op	 326.46 MB/s
BenchmarkReadCrypto4Threads32       	  200000	      7579 ns/op	  16.89 MB/s

// 512 kb reads using 4 threads
BenchmarkRead4Threads512kb           	    1000	   1899048 ns/op	1078.43 MB/s
BenchmarkReadCrypto4Threads512kb    	      20	  97423380 ns/op	  21.02 MB/s

Security

fastrand uses an algorithm similar to Fortuna, which is the basis for the /dev/random device in FreeBSD. However, although the techniques used by fastrand are known to be secure, the specific implementation has not been reviewed by a security professional. Use with caution.

The general strategy is to use crypto/rand at init to get 32 bytes of strong entropy. From there, the entropy is concatenated to a counter and hashed repeatedly, providing 64 bytes of random output each time the counter is incremented. The counter is 16 bytes, which provides strong guarantees that a cycle will not be seen throughout the lifetime of the program.

The sync/atomic package is used to ensure that multiple threads calling fastrand concurrently are always guaranteed to end up with unique counters.

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