crypto / sha1不匹配openssl命令

Question

I'm trying to compute sha1, but the sha1 is not matching with the openssl command.

I compute the hash for an empty file like so on my Macbook :

$ touch test.txt
$ openssl sha1 -hex test.txt
SHA1(test.txt)= da39a3ee5e6b4b0d3255bfef95601890afd80709

And here is the simple test code I have :

package main

import "fmt"
import "crypto/sha1"

func main() {
        hash := sha1.New()
        hash.Write([]byte{0x00})
        fmt.Printf("Hash got %x, expected da39a3ee5e6b4b0d3255bfef95601890afd80709", hash.Sum(nil))
}

Here is the output as you see the output does not match, anyone know what I'm doing wrong?

Hash got 5ba93c9db0cff93f52b521d7420e43f6eda2784f, expected da39a3ee5e6b4b0d3255bfef95601890afd80709

Answer 1

Your Go code is computing the SHA of an input of length 1, with a value of [ 0 ].

The touch command actually creates an empty file (zero length), so the equivalent Go code would be:

hash := sha1.New()
// hash.Write([]byte{}) 
data := hash.Sum(nil)
fmt.Printf("hash: %x", data)

The (commented) Write call above is a no-op. Playground

Your test code does not actually seem to read from a file. Anyway, per your request, here is what a full sha utility would look like in Go:

package main

import (
        "crypto/sha1"
        "fmt"
        "io"
        "log"
        "os"
)

func main() {
        if len(os.Args) < 2 {
                fmt.Printf("usage: %s <file>
", os.Args[0])
                os.Exit(1)
        }

        file := os.Args[1]

        f, err := os.Open(file)

        if err != nil {
                log.Fatal(err)
        }

        defer f.Close()

        hash := sha1.New()

        _, err = io.Copy(hash, f)

        if err != nil {
                log.Fatal(err)
        }

        fmt.Printf("%x
", hash.Sum(nil))
}

Testing it out, I get:

$ touch test.txt
$ go run sha.go test.txt
da39a3ee5e6b4b0d3255bfef95601890afd80709