SHA256 Hashes #

// [_SHA256 hashes_](https://en.wikipedia.org/wiki/SHA-2) 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 (
	"crypto/sha256"
	"fmt"
)

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.
	h.Write([]byte(s))

	// 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.Println(s)
	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
1af1dfa857bf1d8814fe1af8983c18080019922e557f15a8a...


# 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](https://en.wikipedia.org/wiki/Cryptographic_hash_function)!