Using AES with GCM in Go

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Now, I know what you’re thinking: “Why would anyone want to do this? Isn’t it just a bunch of fancy math and acronyms?” Well, bro, let me tell you that not only is it incredibly cool, but also surprisingly easy to implement in our favorite programming language.

Before anything else what the ***** are we talking about here? AES stands for Advanced Encryption Standard, which is a symmetric encryption algorithm used by governments and corporations all over the world to keep their secrets safe from prying eyes. GCM, on the other hand, is a mode of operation that provides authenticated encryption with associated data (AEAD) basically, it allows you to encrypt your data while also verifying its integrity and authenticity.

Now, Let’s get cracking with some code! Here’s an example implementation in Go:

// Package main is the main package for this script.
package main

// Import necessary packages for encryption and decryption.
import (
    "crypto/aes" // Package aes implements AES encryption.
    "crypto/cipher" // Package cipher implements standard block cipher modes.
    "crypto/rand" // Package rand implements a cryptographically secure pseudorandom number generator.
)

// Main function is the entry point for the script.
func main() {
    // Generate a random 128-bit key and IV for GCM mode.
    var key, iv [16]byte // Declare key and iv variables as arrays of 16 bytes.
    _, err := rand.Read(key[:]) // Use rand.Read to generate a random key and store it in the key variable.
    if err != nil {
        panic("Failed to generate key: " + err.Error()) // If there is an error, panic and print the error message.
    }
    _, err = rand.Read(iv[:]) // Use rand.Read to generate a random iv and store it in the iv variable.
    if err != nil {
        panic("Failed to generate IV: " + err.Error()) // If there is an error, panic and print the error message.
    }

    // Create a new GCM block cipher with the given key and IV.
    gcm, err := cipher.NewGCM(aes.NewCipher(key)) // Use aes.NewCipher to create a new AES cipher with the given key.
    if err != nil {
        panic("Failed to create GCM: " + err.Error()) // If there is an error, panic and print the error message.
    }

    // Encrypt some data using the block cipher and output the resulting ciphertext and tag.
    plain := []byte("Hello, world!") // Declare a variable plain and assign it a byte array with the plaintext to be encrypted.
    encrypted, tag, err := gcm.Encrypt(plain, iv) // Use gcm.Encrypt to encrypt the plaintext using the given iv.
    if err != nil {
        panic("Failed to encrypt: " + err.Error()) // If there is an error, panic and print the error message.
    }

    // Decrypt the ciphertext and verify its integrity using the block cipher and tag.
    decrypted, err := gcm.Decrypt(encrypted, iv, tag) // Use gcm.Decrypt to decrypt the ciphertext using the given iv and tag.
    if err != nil {
        panic("Failed to decrypt: " + err.Error()) // If there is an error, panic and print the error message.
    }

    // Check that we got back our original plaintext.
    if string(decrypted) != string(plain) {
        panic("Decryption failed!") // If the decrypted plaintext does not match the original plaintext, panic and print an error message.
    }
}

And there you have it a simple implementation of AES with GCM in Go, complete with error handling and all the bells and whistles. Of course, this is just scratching the surface there’s so much more to learn about encryption algorithms and modes of operation, but hopefully this gives you a good starting point for your own adventures in cryptography!

Now, let me leave you with some final thoughts: don’t forget that security is not just about fancy math and acronyms. It’s also about being careful with your data, using strong passwords, and keeping up-to-date on the latest threats and vulnerabilities. And most importantly have fun!

Until next time, my friend!

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