Secure Data Encryption and Decryption in Go Using AES

package main

import (
	"crypto/aes"
	"crypto/cipher"
	"crypto/rand"
	"encoding/base64"
	"fmt"
	"io"
)

// Function to generate a random 32-byte key.
func generateRandomKey() ([]byte, error) {
	key := make([]byte, 32)
	_, err := rand.Read(key)
	if err != nil {
		return nil, err
	}
	return key, nil
}

// Function to encrypt plaintext using the given key.
func encrypt(plaintext []byte, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

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

	stream := cipher.NewCFBEncrypter(block, iv)
	stream.XORKeyStream(ciphertext[aes.BlockSize:], plaintext)

	return ciphertext, nil
}

// Function to decrypt ciphertext using the given key.
func decrypt(ciphertext []byte, key []byte) ([]byte, error) {
	block, err := aes.NewCipher(key)
	if err != nil {
		return nil, err
	}

	if len(ciphertext) < aes.BlockSize {
		return nil, fmt.Errorf("ciphertext too short")
	}
	iv := ciphertext[:aes.BlockSize]
	ciphertext = ciphertext[aes.BlockSize:]

	stream := cipher.NewCFBDecrypter(block, iv)
	stream.XORKeyStream(ciphertext, ciphertext)

	return ciphertext, nil
}

func main() {
	// Example usage
	plaintext := []byte("This is the plaintext to be encrypted!89")

	key, err := generateRandomKey()
	if err != nil {
		fmt.Println("Error generating key:", err)
		return
	}

	ciphertext, err := encrypt(plaintext, key)
	if err != nil {
		fmt.Println("Error encrypting:", err)
		return
	}

	fmt.Println("Ciphertext:", base64.StdEncoding.EncodeToString(ciphertext))

	decryptedText, err := decrypt(ciphertext, key)
	if err != nil {
		fmt.Println("Error decrypting:", err)
		return
	}

	fmt.Println("Decrypted text:", string(decryptedText))
}