encryption.go

package encryption

import (
	"crypto/aes"
	"crypto/cipher"
	"crypto/hmac"
	"crypto/md5"
	"crypto/rand"
	"crypto/sha256"
	"encoding/base64"
	"fmt"
	"gitlab.bob.co.za/bob-public-utils/bobgroup-go-utils/errors"
	"io"
)

func Hash(input string, key string) string {
	keyBytes := []byte(key)
	h := hmac.New(sha256.New, keyBytes)
	h.Write([]byte(input))
	return base64.StdEncoding.EncodeToString(h.Sum(nil))
}

func Md5HashString(bytesToHash []byte) string {
	hash := md5.Sum(bytesToHash)
	hashString := fmt.Sprintf("%X", hash)
	return hashString
}

func Encrypt(plaintext string, key string) (string, error) {
	if len(key) != 32 {
		return "", errors.New("key should be 32 bytes")
	}

	block, err := aes.NewCipher([]byte(key))
	if err != nil {
		return "", err
	}

	aesGcm, err := cipher.NewGCM(block)
	if err != nil {
		return "", err
	}

	nonce := make([]byte, aesGcm.NonceSize())
	if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
		return "", err
	}

	return string(aesGcm.Seal(nonce, nonce, []byte(plaintext), nil)), nil
}

func Decrypt(ciphertext string, key string) (string, error) {
	if len(key) != 32 {
		return "", errors.New("key should be 32 bytes")
	}

	block, err := aes.NewCipher([]byte(key))
	if err != nil {
		return "", err
	}

	aesGcm, err := cipher.NewGCM(block)
	if err != nil {
		return "", err
	}

	nonceSize := aesGcm.NonceSize()
	if len(ciphertext) < nonceSize {
		return "", errors.New("ciphertext too short")
	}