AES-CBC application

main.go

package main

import (
        "crypto/aes"
        "crypto/cipher"
        "crypto/rand"
        "encoding/hex"
        "fmt"
        "io"
        "os"

        "github.com/gdamore/encoding"
)

func main() {
        // don't hardcode encryption keys in real life pls
        key, _ := hex.DecodeString("96744014bfa48166206212b1f8655b66811bf6718a31369c1956a2059d2ba0ba")
        if os.Args[1] == "encrypt" {
                encrypt(toASCII(os.Args[2]), key)
        } else if os.Args[1] == "decrypt" {
                iv, _ := hex.DecodeString(os.Args[2])
                ciphertext, _ := hex.DecodeString(os.Args[3])
                decrypt(iv, ciphertext, key)
        }
}

func toASCII(plaintext string) []byte {
        encoder := encoding.ASCII.NewEncoder()
        result, _ := encoder.Bytes([]byte(plaintext))
        return result
}

func encrypt(plaintext, key []byte) {
        // generate unique IV
        iv := make([]byte, aes.BlockSize)
        io.ReadFull(rand.Reader, iv)

        //instantiate block cipher
        block, _ := aes.NewCipher(key)
        mode := cipher.NewCBCEncrypter(block, iv)

        // encrypt
        ciphertext := make([]byte, len(plaintext))
        mode.CryptBlocks(ciphertext, plaintext)

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

func decrypt(iv, ciphertext, key []byte) {
        // instantiate block cipher
        block, _ := aes.NewCipher(key)
        mode := cipher.NewCBCDecrypter(block, iv)

        // decrypt
        plaintext := make([]byte, len(ciphertext))
        mode.CryptBlocks(plaintext, ciphertext)
        fmt.Printf("plaintext: %s\n", plaintext)
}