fastrand

README

fastrand

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Documentation

Overview

Package 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 at init.

The method used in this package is similar to the Fortuna algorithm, which is used in used in FreeBSD for /dev/urandom. This package uses techniques that are known to be secure, however the exact implementation has not been heavily reviewed by cryptographers.

Index

• Variables
• func BigIntn(n *big.Int) *big.Int
• func Bytes(n int) []byte
• func Intn(n int) int
• func Perm(n int) []int
• func Read(b []byte)
• func Uint64n(n uint64) uint64

Variables

var Reader io.Reader

Reader is a global, shared instance of a cryptographically strong pseudo- random generator. It uses blake2b as its hashing function. Reader is safe for concurrent use by multiple goroutines.

Functions

func BigIntn

func BigIntn(n *big.Int) *big.Int

BigIntn returns a uniform random *big.Int in [0,n). It panics if n <= 0.

func Bytes

func Bytes(n int) []byte

Bytes is a helper function that returns n bytes of random data.

func Intn

func Intn(n int) int

Intn returns a uniform random int in [0,n). It panics if n <= 0.

func Perm

func Perm(n int) []int

Perm returns a random permutation of the integers [0,n).

func Read

func Read(b []byte)

Read is a helper function that calls Reader.Read on b. It always fills b completely.

func Uint64n

func Uint64n(n uint64) uint64

Uint64n returns a uniform random uint64 in [0,n). It panics if n == 0.