user_passwor.go

package main

import (
    "fmt"
    "log"

    "golang.org/x/crypto/bcrypt"
)

func main() {
    userPassword1 := "some user-provided password"

    // Generate "hash" to store from user password
    hash, err := bcrypt.GenerateFromPassword([]byte(userPassword1), bcrypt.DefaultCost)
    if err != nil {
        // TODO: Properly handle error
        log.Fatal(err)
    }
    fmt.Println("Hash to store:", string(hash))
    // Store this "hash" somewhere, e.g. in your database

    // After a while, the user wants to log in and you need to check the password he entered
    userPassword2 := "some user-provided password"
    hashFromDatabase := hash

    // Comparing the password with the hash
    if err := bcrypt.CompareHashAndPassword(hashFromDatabase, []byte(userPassword2)); err != nil {
        // TODO: Properly handle error
        log.Fatal(err)
    }

    fmt.Println("Password was correct!")
}