Go by Example: SHA256 Hashes

SHA256 hashes are frequently used to compute short identities for binary or text blobs. For example, TLS/SSL certificates use SHA256 to compute a certificate’s signature. Here’s how to compute SHA256 hashes in Go.

package main

Go implements several hash functions in various crypto/* packages.

import (
func main() {
    s := "sha256 this string"

Here we start with a new hash.

    h := sha256.New()

Write expects bytes. If you have a string s, use []byte(s) to coerce it to bytes.


This gets the finalized hash result as a byte slice. The argument to Sum can be used to append to an existing byte slice: it usually isn’t needed.

    bs := h.Sum(nil)
    fmt.Printf("%x\n", bs)

Running the program computes the hash and prints it in a human-readable hex format.

$ go run sha256-hashes.go
sha256 this string

You can compute other hashes using a similar pattern to the one shown above. For example, to compute SHA512 hashes import crypto/sha512 and use sha512.New().

Note that if you need cryptographically secure hashes, you should carefully research hash strength!

Next example: Base64 Encoding.