AES Encryption and Decryption in GO

example.go

package main

import (
	"crypto/aes"
	"crypto/cipher"
	"crypto/rand"
	"crypto/sha256"
	"fmt"
	"io"
)

const SECRET = "Hello This is a new secret! Now even longer"

func main() {
	encryptedData, _ := encrypt("Testing AES encryption!")
	fmt.Printf("%x \n", encryptedData)
	result, _ := decrypt(encryptedData)
	fmt.Printf("%s\n", result)

}

func encrypt(text string) ([]byte, error) {
	key := sha256.Sum256([]byte(SECRET))
	block, err := aes.NewCipher(key[:])
	if err != nil {
		return nil, err
	}

	fmt.Printf("%d bytes NewCipher key with block size of %d bytes\n", len(key), block.BlockSize())

	cipherText := make([]byte, len(text)+aes.BlockSize)
	iv := cipherText[:aes.BlockSize]
	if _, err = io.ReadFull(rand.Reader, iv); err != nil {
		return nil, err
	}

	fmt.Printf("IV: %x\n", iv)

	enc := cipher.NewCFBEncrypter(block, iv)
	enc.XORKeyStream(cipherText[aes.BlockSize:], []byte(text))
	return cipherText, nil
}

func decrypt(cipherData []byte) (string, error) {
	key := sha256.Sum256([]byte(SECRET))
	block, err := aes.NewCipher(key[:])
	if err != nil {
		return "", err
	}

	if len(cipherData) < aes.BlockSize {
		return "", fmt.Errorf("Invalid text")
	}

	data := cipherData[aes.BlockSize:]
	iv := cipherData[:aes.BlockSize]

	cfb := cipher.NewCFBDecrypter(block, iv)
	cfb.XORKeyStream(data, data)

	return string(data), nil
}