Security with Go

Hashing small files

If a file is small enough to be contained in memory, the ReadFile() method works quickly. It loads the whole file into memory and then digests the data. The sum will be calculated with multiple different hash algorithms for demonstration:

package mainimport (   "crypto/md5"   "crypto/sha1"   "crypto/sha256"   "crypto/sha512"   "fmt"   "io/ioutil"   "log"   "os")func printUsage() {   fmt.Println("Usage: " + os.Args[0] + " <filepath>")   fmt.Println("Example: " + os.Args[0] + " document.txt")}func checkArgs() string {   if len(os.Args) < 2 {      printUsage()      os.Exit(1)   }   return os.Args[1]}func main() {   filename := checkArgs()   // Get bytes from file   data, err := ioutil.ReadFile(filename)   if err != nil {      log.Fatal(err)   } // Hash the file and output ...