How is information protected using encryption and decryption methods?

Information protection using encryption and decryption methods involves transforming data into a format that is inaccessible without a special key or algorithm.

Main stages:

1. Encryption — the original data (plaintext) is transformed into encrypted text (ciphertext) using an algorithm and a key. This prevents unauthorized access.

2. Decryption — the reverse process, where the encrypted text is transformed back into the original data using a key.

In Go, packages from the standard library are often used for this, such as crypto/aes for symmetric encryption or crypto/rsa for asymmetric encryption.

Example of simple symmetric encryption with AES:

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

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
}

Thus, encryption ensures data confidentiality, and decryption allows authorized users to restore the data.