Documentation

Overview

    Package rand implements a cryptographically secure random number generator.

    Index

    Examples

    Constants

    This section is empty.

    Variables

    View Source
    var Reader io.Reader

      Reader is a global, shared instance of a cryptographically secure random number generator.

      On Linux and FreeBSD, Reader uses getrandom(2) if available, /dev/urandom otherwise. On OpenBSD, Reader uses getentropy(2). On other Unix-like systems, Reader reads from /dev/urandom. On Windows systems, Reader uses the RtlGenRandom API. On Wasm, Reader uses the Web Crypto API.

      Functions

      func Int

      func Int(rand io.Reader, max *big.Int) (n *big.Int, err error)

        Int returns a uniform random value in [0, max). It panics if max <= 0.

        func Prime

        func Prime(rand io.Reader, bits int) (p *big.Int, err error)

          Prime returns a number, p, of the given size, such that p is prime with high probability. Prime will return error for any error returned by rand.Read or if bits < 2.

          func Read

          func Read(b []byte) (n int, err error)

            Read is a helper function that calls Reader.Read using io.ReadFull. On return, n == len(b) if and only if err == nil.

            Example

              This example reads 10 cryptographically secure pseudorandom numbers from rand.Reader and writes them to a byte slice.

              Code:

              package main
              
              import (
              	"bytes"
              	"crypto/rand"
              	"fmt"
              )
              
              func main() {
              	c := 10
              	b := make([]byte, c)
              	_, err := rand.Read(b)
              	if err != nil {
              		fmt.Println("error:", err)
              		return
              	}
              	// The slice should now contain random bytes instead of only zeroes.
              	fmt.Println(bytes.Equal(b, make([]byte, c)))
              
              }
              
              false
              

              Types

              This section is empty.
              GOOS=linux, GOARCH=amd64