无法在 Rust 上解密 AES 密钥

Question

我想提一下，我对 Rust 完全陌生，我要分享的代码只是一个帮助我学习该语言的练习：

src/main.rs

use openssl::{
    pkey::PKey,
    rsa::{Padding, Rsa},
    symm::{Cipher, Crypter, Mode},
    encrypt::Decrypter,
};
use rpassword::read_password_from_tty;
use std::net::SocketAddr;
use tokio::{
    net::UdpSocket,
};

#[tokio::main]
async fn main() {
    // Load the private key
    println!("Enter RSA private key passphrase:");
    let passphrase = read_password_from_tty(Some("Passphrase: ")).expect("Failed to read passphrase");

    let private_key = include_bytes!("private_key_enc2.pem");
    let rsa = Rsa::private_key_from_pem_passphrase(private_key, passphrase.as_bytes()).expect("Failed to load private key");
    let pkey = PKey::from_rsa(rsa).expect("Failed to create PKey from RSA");

    // Start the UDP server
    let addr: SocketAddr = "0.0.0.0:12345".parse().expect("Invalid socket address");
    let socket = UdpSocket::bind(&addr)
        .await
        .expect("Failed to bind to the socket");
    println!("Server listening on {}", addr);

    let mut buf = [0; 65535]; // A buffer large enough for UDP packet
    loop {
        // Receive the encrypted message
        let (len, _src) = socket.recv_from(&mut buf).await.expect("Failed to read from socket");
        let data = &buf[..len];

        // Extract the RSA-encrypted AES key, IV, and encrypted message by their lengths
        // encrypted AES key length = 2048 bytes (16384 bits)
        let (encrypted_aes_key, rest) = data.split_at(2048);
        // IV length = 16 bytes for AES-256-CBC
        let (iv, encrypted_message) = rest.split_at(16);

        // Decrypt the AES key
        let mut decrypter = Decrypter::new(&pkey).expect("Failed to create decrypter");
        decrypter.set_rsa_padding(Padding::PKCS1_OAEP).expect("Failed to set padding");
        decrypter.set_rsa_oaep_md(openssl::hash::MessageDigest::sha256()).expect("Failed to set OAEP digest");
        decrypter.set_rsa_mgf1_md(openssl::hash::MessageDigest::sha256()).expect("Failed to set MGF1 digest");
        let mut aes_key = vec![0; pkey.size()];
        let aes_key_len = decrypter.decrypt(encrypted_aes_key, &mut aes_key).expect("Failed to decrypt AES key");
        aes_key.truncate(aes_key_len);

        // Decrypt the message using AES-256-CBC
        let cipher = Cipher::aes_256_cbc();
        let mut crypter = Crypter::new(cipher, Mode::Decrypt, &aes_key, Some(iv)).expect("Failed to create AES crypter");
        let mut plaintext = vec![0; encrypted_message.len() + cipher.block_size()];
        let count = crypter.update(encrypted_message, &mut plaintext).expect("Failed to decrypt message");
        let rest = crypter.finalize(&mut plaintext[count..]).expect("Failed to finalize decryption");
        plaintext.truncate(count + rest);

        // Print the decrypted message
        let message = String::from_utf8(plaintext).expect("Failed to parse plaintext as UTF-8");
        println!("Received and decrypted message: {}", message);
    }
}

货物.toml

...

[dependencies]
openssl = "0.10"
tokio = { version = "1", features = ["full"] }
rpassword = "5.0.1"

该代码在 Ubuntu 上可以正常工作，这意味着它可以接受、解密并显示 Android 应用程序发送的消息，但在 Windows 上无法工作：

thread 'main' panicked at src\main.rs:36:14:
Failed to decrypt AES key: ErrorStack([Error { code: 33554553, library: "rsa routines", function: "RSA_padding_check_PKCS1_OAEP_mgf1", reason: "oaep decoding error", file: "crypto\\rsa\\rsa_oaep.c", line: 314 }, Error { code: 33554546, library: "rsa routines", function: "rsa_ossl_private_decrypt", reason: "padding check failed", file: "crypto\\rsa\\rsa_ossl.c", line: 499 }])

我在 Windows 上安装了 OpenSSL (

choco install openssl

) 并设置了环境变量 (

OPENSSL_DIR

、

OPENSSL_INCLUDE_DIR

和

OPENSSL_LIB_DIR

)。编译期间没有显示错误或警告。

我怀疑问题在于 Windows (3.1.1) 上的 OpenSSL 版本，它与 Ubuntu (3.0.2) 上的版本不同。

我不确定如何解决这个问题。有人可以提供一些解决方案的指导或建议吗？

---

PS：我尝试在 Ubuntu 上对 x86_64-pc-windows-gnu 目标进行交叉编译，但没有成功。

Answer 1

我使用的是 16384 位的非常大的 RSA 密钥，由于当时是深夜，我可能混淆了密钥。然而，在创建一组具有较小 RSA 密钥大小 (2048) 的新密钥并在第二天重新审视它们后，一切都正常运行。

我希望这可以帮助将来遇到同样问题的其他用户。