package rand

Import Path
	crypto/rand (on golang.org and go.dev)

Dependency Relation
	imports 15 packages, and imported by 5 packages

Involved Source Files eagain.go Package rand implements a cryptographically secure random number generator. rand_batched.go rand_linux.go rand_unix.go util.go
Code Examples 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))) }
Package-Level Functions (total 3)
Int returns a uniform random value in [0, max). It panics if max <= 0.
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.
Read is a helper function that calls Reader.Read using io.ReadFull. On return, n == len(b) if and only if err == nil.
Package-Level Variables (only one)
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.