rust - 基于AES-CBC-128的双重加密实现

通常加密密钥不要出现在源码中，比如配置文件中的数据库密码等。解决方案通常采用将密钥存放在环境变量中，进程启动时从环境变量获取密钥加载到内存中。

还有一种方案，对密钥进行加密，源码中只包含对密钥加密的根密钥和对密钥加密后的二次密钥，如果不知道加密方式，在编译出来的二进制文件中很难还原出真实的密钥。

安装依赖

cargo add base64
cargo add rust-crypto

AES128加解密算法

use base64::{engine::general_purpose, Engine as _};
use crypto::buffer::{BufferResult, ReadBuffer, WriteBuffer};
use crypto::{aes, blockmodes, buffer, symmetriccipher};


pub fn aes128_cbc_encrypt(
    data: &[u8],
    key: &[u8],
    iv: &[u8],
) -> Result<Vec<u8>, symmetriccipher::SymmetricCipherError> {
    let mut encryptor = aes::cbc_encryptor(
        aes::KeySize::KeySize128,
        key,
        iv,
        blockmodes::PkcsPadding,
    );

    let mut final_result = Vec::<u8>::new();
    let mut read_buffer = buffer::RefReadBuffer::new(data);
    let mut buffer = [0; 4096];
    let mut write_buffer = buffer::RefWriteBuffer::new(&mut buffer);

    loop {
        let result =
            encryptor.encrypt(&mut read_buffer, &mut write_buffer, true)?;

        final_result.extend(
            write_buffer
                .take_read_buffer()
                .take_remaining()
                .iter()
                .map(|&i| i),
        );

        match result {
            BufferResult::BufferUnderflow => break,
            BufferResult::BufferOverflow => {}
        }
    }

    Ok(final_result)
}

pub fn aes128_cbc_decrypt(
    encrypted_data: &[u8],
    key: &[u8],
    iv: &[u8],
) -> Result<Vec<u8>, symmetriccipher::SymmetricCipherError> {
    let mut decryptor = aes::cbc_decryptor(
        aes::KeySize::KeySize128,
        key,
        iv,
        blockmodes::PkcsPadding,
    );

    let mut final_result = Vec::<u8>::new();
    let mut read_buffer = buffer::RefReadBuffer::new(encrypted_data);
    let mut buffer = [0; 4096];
    let mut write_buffer = buffer::RefWriteBuffer::new(&mut buffer);

    loop {
        let result =
            decryptor.decrypt(&mut read_buffer, &mut write_buffer, true)?;
        final_result.extend(
            write_buffer
                .take_read_buffer()
                .take_remaining()
                .iter()
                .map(|&i| i),
        );
        match result {
            BufferResult::BufferUnderflow => break,
            BufferResult::BufferOverflow => {}
        }
    }

    Ok(final_result)
}

base64编码得到二次密钥

将加密后的秘钥存放在配置文件中。

pub fn aes128_base64_encrypt(
    key: &[u8],
    iv: &[u8],
    plain_text: &[u8],
) -> String {
    let output = aes128_cbc_encrypt(plain_text, &key, &iv).unwrap();
    general_purpose::STANDARD.encode(&output)
}

base64解码获得真实的密钥

首先从配置文件中获取二次加密的秘钥，解密获得真实的秘钥，然后再用解密后的秘钥对密文进行解密 或 对明文进行加密。

pub fn aes128_base64_decrypt(
    key: &[u8],
    iv: &[u8],
    cipher_text: &[u8],
) -> Result<Vec<u8>, symmetriccipher::SymmetricCipherError> {
    let data = general_purpose::STANDARD.decode(cipher_text).unwrap();
    aes128_cbc_decrypt(&data, &key, &iv)
}

单元测试

#[test]
fn test_aes128_cbc() {
    let key = get_random_key16();
    let iv = generate_iv();

    // 加密
    let plain_text = "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ！".to_string();
    let cipher_text = aes128_base64_encrypt(&key, &iv, plain_text.as_bytes());
    // 加密
    let output =
        aes128_base64_decrypt(&key, &iv, cipher_text.as_bytes()).unwrap();
    let plain_text_2 = String::from_utf8(output).unwrap();

    assert_eq!(plain_text, plain_text_2);
}