Rust user input validation: Efficient error propagation

Rust Error Propagation: Exercise-6 with Solution

Write a Rust function that performs cryptographic operations (e.g., encryption, decryption) and handles errors.

Sample Solution:

Rust Code:

use openssl::symm::{Cipher, Crypter, Mode};
use rand::rngs::OsRng;
use rand::RngCore;
use std::error::Error;

/// Function to generate a random key for encryption
fn generate_key() -> [u8; 32] {
    let mut key = [0; 32];
    let mut rng = OsRng;
    rng.fill_bytes(&mut key);
    key
}

/// Function to encrypt data using AES encryption in ECB mode
fn encrypt_data(data: &[u8], key: &[u8]) -> Result<Vec<u8>, Box<dyn Error>> {
    let cipher = Cipher::aes_256_ecb(); // Use AES-256 ECB cipher
    let mut crypter = Crypter::new(cipher, Mode::Encrypt, key, None)?;
    let mut encrypted_data = vec![0; data.len() + cipher.block_size()];
    let count = crypter.update(data, &mut encrypted_data)?;
    let final_count = crypter.finalize(&mut encrypted_data[count..])?;
    encrypted_data.truncate(count + final_count);
    Ok(encrypted_data)
}

/// Function to decrypt data using AES decryption in ECB mode
fn decrypt_data(encrypted_data: &[u8], key: &[u8]) -> Result<Vec<u8>, Box<dyn Error>> {
    let cipher = Cipher::aes_256_ecb(); // Use AES-256 ECB cipher
    let mut crypter = Crypter::new(cipher, Mode::Decrypt, key, None)?;
    let mut decrypted_data = vec![0; encrypted_data.len() + cipher.block_size()];
    let count = crypter.update(encrypted_data, &mut decrypted_data)?;
    let final_count = crypter.finalize(&mut decrypted_data[count..])?;
    decrypted_data.truncate(count + final_count);
    Ok(decrypted_data)
}

fn main() -> Result<(), Box<dyn Error>> {
    let data = b"Hello, world!"; 

    let key = generate_key(); // Generate a random key
    println!("Generated key: {:?}", key);

    let encrypted_data = encrypt_data(data, &key)?;
    println!("Encrypted data: {:?}", encrypted_data);

    let decrypted_data = decrypt_data(&encrypted_data, &key)?;
    println!("Decrypted data: {:?}", decrypted_data);

    Ok(())
}

Output:

Generated key: [184, 119, 57, 95, 175, 254, 64, 238, 156, 211, 179, 54, 0, 113, 240, 89, 60, 67, 249, 15, 146, 216, 217, 116, 242, 135, 55, 84, 11, 166, 31, 235]
Encrypted data: [5, 248, 93, 232, 155, 127, 43, 70, 168, 30, 255, 202, 218, 163, 124, 179]
Decrypted data: [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33]

Explanation:

Here is a brief explanation of the above Rust code:

• Imports:
• openssl::symm::{Cipher, Crypter, Mode}: Import necessary modules from the openssl crate for cryptographic operations.
• rand::rngs::OsRng: Import the OsRng type for generating random numbers.
• rand::RngCore: Import the RngCore trait for generating random numbers.
• std::error::Error: Import the Error trait for error handling.
• Function generate_key():
• Generates a random 256-bit key for encryption using AES-256.
• Function encrypt_data():
• Encrypt the provided data using AES-256 ECB mode.
• Initializes a Crypter object with the AES-256 ECB cipher and encryption mode.
• Updates the crypter with the input data and stores the encrypted data in a vector.
• Finalizes the encryption process and truncates the encrypted data to the correct size.
• Returns the encrypted data as a vector.
• Function decrypt_data():
• Decrypt the provided encrypted data using AES-256 ECB mode.
• Initializes a Crypter object with the AES-256 ECB cipher and decryption mode.
• Updates the crypter with the encrypted data and stores the decrypted data in a vector.
• Finalizes the decryption process and truncates the decrypted data to the correct size.
• Returns the decrypted data as a vector.
• Function main():
• Generate a random key using "generate_key()".
• Encrypts the data "Hello, world!" using the generated key and prints the encrypted data.
• Decrypts the encrypted data using the same key and prints the decrypted data.
• Handle any errors during encryption, decryption, or printing.

Rust Code Editor:

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