How to get a MD5 hash from a string in Golang?

Question

This is how I started to get a md5 hash from a string:

import "crypto/md5"

var original = "my string comes here"
var hash = md5.New(original)

But obviously this is not how it works. Can someone provide me a working sample for this?

Powe

The very best answer to this question is in the comments by @Alexei Danchenkov below. I've implemented them in a quick runnable example here: play.golang.org/p/e7v_erP7Gc – Kathrinekathryn

Answer 1

Reference Sum，For me，following work well：

package main

import (
    "crypto/md5"
    "fmt"
)

func main() {
    data := []byte("hello")
    fmt.Printf("%x", md5.Sum(data))
}

Grudge

Answer 2

import (
    "crypto/md5"
    "encoding/hex"
)

func GetMD5Hash(text string) string {
   hash := md5.Sum([]byte(text))
   return hex.EncodeToString(hash[:])
}

Catalpa

Well done! I personally like that your simple wrapping works 'transparently' in the sense that so many other programming languages do the same thing... – Connecticut

what is the purpose of hash[:]? Thanks – Polygon

@Madeo it means a slice which referencing the storage of (variable) hash, for the detail You can see here blog.golang.org/slices-intro – Voigt

Answer 3

I found this solution to work well

package main

import (
    "crypto/md5"
    "encoding/hex"
    "fmt"
)

func main() {
    var str string = "hello world"

    hasher := md5.New()
    hasher.Write([]byte(str))
    fmt.Println(str)
    fmt.Println(hex.EncodeToString(hasher.Sum(nil)))
}

Govan

Answer 4

From crypto/md5 doc:

package main

import (
    "crypto/md5"
    "fmt"
    "io"
)

func main() {
    h := md5.New()
    io.WriteString(h, "The fog is getting thicker!")
    fmt.Printf("%x", h.Sum(nil))
}

Unparalleled

strings.Bytes doesn't exist anymore on -release, it's []byte(original) – Baro

Looks like Hash.Sum() needs a byte slice as first argument now. h.Sum([]byte{}) will fix this example. – Honniball

I have seen the documentation that this example is taken from but you haven't added anything to it, like an explanation for example. Why is io.WriteString() required? Why does h.Sum() require nil as an argument rather than taking the given string? A a GoNoob reading parroted examples is rather unedifying. – Kafiristan

@IanLewis Writer io.WriteString() is unrelated to the subject. fmt.Fprintf(h, "The fog is getting thicker!") would produce the same result. Even clearer would be a one-liner fmt.Printf("%x\n", md5.Sum([]byte("The quick brown fox jumps over the lazy dog."))). h.Sum(in) called with any in would append the md5-hash of h to in - i.e. concatenate them (see the source, line 88: golang.org/src/pkg/crypto/md5/md5.go?s=2281:2313#L88). – Karisakarissa

Well. I would like to get the string instead of printing it to the console O.o... – Eidetic

Answer 5

I use this to MD5 hash my strings:

import (
    "crypto/md5"
    "encoding/hex"
)

func GetMD5Hash(text string) string {
    hasher := md5.New()
    hasher.Write([]byte(text))
    return hex.EncodeToString(hasher.Sum(nil))
}

Universalize

Answer 6

Here is a function you could use to generate an MD5 hash:

// MD5 hashes using md5 algorithm
func MD5(text string) string {
    algorithm := md5.New()
    algorithm.Write([]byte(text))
    return hex.EncodeToString(algorithm.Sum(nil))
}

I put together a group of those utility hash functions here: https://github.com/shomali11/util

You will find FNV32, FNV32a, FNV64, FNV65a, MD5, SHA1, SHA256 and SHA512

Zoophilia

Well done, but your answer comes late... the same answer has already been provided three years before yours! – Connecticut

Answer 7

just another answer

// MD5 hashes using md5 algorithm
func MD5(text string) string {
    data := []byte(text)
    return fmt.Sprintf("%x", md5.Sum(data))
}

Tillietillinger

That's litterally the content of the accepted answer. – Kassiekassity

Improved and simplified version :), – Tillietillinger

Could you explain the difference between your answer and https://mcmap.net/q/203447/-how-to-get-a-md5-hash-from-a-string-in-golang ? – Kassiekassity