How to properly seed random number generator

In Go, setting the seed for a random number generator typically involves the math/rand package. This package provides functionality for pseudo-random number generation. The rand.Seed function is used to initialize the seed for the default random number generator. If no seed is set, the random number generator defaults to seed 1, which causes the same sequence of random numbers to be generated each time the program runs.

To generate different sequences of random numbers, we should provide a varying seed before using the random number generator. Typically, we use the current time as the seed because it is always changing. Here is an example of how to set the random number seed:

go
package main

import (
    "fmt"
    "math/rand"
    "time"
)

func main() {
    // Use the current time's nanosecond timestamp to initialize the seed
    rand.Seed(time.Now().UnixNano())

    // Generate a random number
    randomNumber := rand.Intn(100) // Generate a random number in [0, 100)
    fmt.Println(randomNumber)
}

In this code snippet, we use time.Now().UnixNano() to obtain the current time's nanosecond timestamp and pass it as a parameter to the rand.Seed function. This way, each time the program runs, the seed changes due to time variation, resulting in the random number generator producing different sequences of random numbers.

It is important to note that the math/rand package generates pseudo-random numbers, which are produced by deterministic algorithms. Therefore, they are not suitable for all scenarios, especially those with high security requirements. For random numbers requiring cryptographic security, the crypto/rand package should be used.