Go SHA-512 Hash Code Example (Online Runner)

Go SHA-512 hashing code example with runnable snippets to calculate SHA-512 for text and files.

Online calculator: use the site SHA-512 text tool.

Calculation method

Use crypto/sha512, hash UTF-8 bytes, and encode the 64-byte digest as hex.

Implementation notes

Package: built-in crypto/sha512.
Implementation: file hashing streams bytes to avoid loading large files into memory.
Notes: SHA-512 is unkeyed; use HMAC for integrity or a KDF for passwords.

Text hashing example

package main

import (
	"crypto/sha512"
	"encoding/hex"
	"fmt"
)

func sha512Text(text string) string {
	sum := sha512.Sum512([]byte(text))
	return hex.EncodeToString(sum[:])
}

func main() {
	fmt.Println(sha512Text("hello world"))
}

File hashing example

package main

import (
	"crypto/sha512"
	"encoding/hex"
	"fmt"
	"io"
	"os"
)

func sha512File(path string) (string, error) {
	file, err := os.Open(path)
	if err != nil {
		return "", err
	}
	defer file.Close()

	hash := sha512.New()
	if _, err := io.Copy(hash, file); err != nil {
		return "", err
	}
	return hex.EncodeToString(hash.Sum(nil)), nil
}

func main() {
	file, err := os.CreateTemp("", "sha512-example-*.bin")
	if err != nil {
		panic(err)
	}
	defer os.Remove(file.Name())
	if _, err := file.Write([]byte("example payload\n")); err != nil {
		panic(err)
	}
	if err := file.Close(); err != nil {
		panic(err)
	}

	value, err := sha512File(file.Name())
	if err != nil {
		panic(err)
	}
	fmt.Println(value)
}

Complete script (implementation + tests)

package main

import (
	"crypto/sha512"
	"encoding/hex"
	"fmt"
	"io"
	"os"
)

func sha512Hex(data []byte) string {
	sum := sha512.Sum512(data)
	return hex.EncodeToString(sum[:])
}

func sha512Text(text string) string {
	return sha512Hex([]byte(text))
}

func sha512File(path string) (string, error) {
	file, err := os.Open(path)
	if err != nil {
		return "", err
	}
	defer file.Close()

	hash := sha512.New()
	if _, err := io.Copy(hash, file); err != nil {
		return "", err
	}
	return hex.EncodeToString(hash.Sum(nil)), nil
}

func main() {
	vectors := map[string]string{
		"":                "cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e",
		"abc":             "ddaf35a193617abacc417349ae20413112e6fa4e89a97ea20a9eeee64b55d39a2192992a274fc1a836ba3c23a3feebbd454d4423643ce80e2a9ac94fa54ca49f",
		"message digest":  "107dbf389d9e9f71a3a95f6c055b9251bc5268c2be16d6c13492ea45b0199f3309e16455ab1e96118e8a905d5597b72038ddb372a89826046de66687bb420e7c",
		"abcdefghijklmnopqrstuvwxyz": "4dbff86cc2ca1bae1e16468a05cb9881c97f1753bce3619034898faa1aabe429955a1bf8ec483d7421fe3c1646613a59ed5441fb0f321389f77f48a879c7b1f1",
	}

	for input, expected := range vectors {
		if got := sha512Text(input); got != expected {
			panic(fmt.Sprintf("SHA-512 mismatch for %q: %s != %s", input, got, expected))
		}
	}

	file, err := os.CreateTemp("", "sha512-example-*.bin")
	if err != nil {
		panic(err)
	}
	defer os.Remove(file.Name())
	if _, err := file.Write([]byte("example payload\n")); err != nil {
		panic(err)
	}
	if err := file.Close(); err != nil {
		panic(err)
	}

	fileHash, err := sha512File(file.Name())
	if err != nil {
		panic(err)
	}
	fmt.Println("sha512(file)=", fileHash)
	fmt.Println("All SHA-512 test vectors passed.")
}