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|
//! Envelope encryption.
//!
//! # Example
//!
//! ```rust
//! use openssl::rsa::Rsa;
//! use openssl::envelope::Seal;
//! use openssl::pkey::PKey;
//! use openssl::symm::Cipher;
//!
//! let rsa = Rsa::generate(2048).unwrap();
//! let key = PKey::from_rsa(rsa).unwrap();
//!
//! let cipher = Cipher::aes_256_cbc();
//! let mut seal = Seal::new(cipher, &[key]).unwrap();
//!
//! let secret = b"My secret message";
//! let mut encrypted = vec![0; secret.len() + cipher.block_size()];
//!
//! let mut enc_len = seal.update(secret, &mut encrypted).unwrap();
//! enc_len += seal.finalize(&mut encrypted[enc_len..]).unwrap();
//! encrypted.truncate(enc_len);
//! ```
use crate::cipher::CipherRef;
use crate::cipher_ctx::CipherCtx;
use crate::error::ErrorStack;
use crate::pkey::{HasPrivate, HasPublic, PKey, PKeyRef};
use crate::symm::Cipher;
use foreign_types::ForeignTypeRef;
/// Represents an EVP_Seal context.
pub struct Seal {
ctx: CipherCtx,
iv: Option<Vec<u8>>,
enc_keys: Vec<Vec<u8>>,
}
impl Seal {
/// Creates a new `Seal`.
pub fn new<T>(cipher: Cipher, pub_keys: &[PKey<T>]) -> Result<Seal, ErrorStack>
where
T: HasPublic,
{
let mut iv = cipher.iv_len().map(|len| vec![0; len]);
let mut enc_keys = vec![vec![]; pub_keys.len()];
let mut ctx = CipherCtx::new()?;
ctx.seal_init(
Some(unsafe { CipherRef::from_ptr(cipher.as_ptr() as *mut _) }),
pub_keys,
&mut enc_keys,
iv.as_deref_mut(),
)?;
Ok(Seal { ctx, iv, enc_keys })
}
/// Returns the initialization vector, if the cipher uses one.
#[allow(clippy::option_as_ref_deref)]
pub fn iv(&self) -> Option<&[u8]> {
self.iv.as_ref().map(|v| &**v)
}
/// Returns the encrypted keys.
pub fn encrypted_keys(&self) -> &[Vec<u8>] {
&self.enc_keys
}
/// Feeds data from `input` through the cipher, writing encrypted bytes into `output`.
///
/// The number of bytes written to `output` is returned. Note that this may
/// not be equal to the length of `input`.
///
/// # Panics
///
/// Panics if `output.len() < input.len() + block_size` where `block_size` is
/// the block size of the cipher (see `Cipher::block_size`), or if
/// `output.len() > c_int::max_value()`.
pub fn update(&mut self, input: &[u8], output: &mut [u8]) -> Result<usize, ErrorStack> {
self.ctx.cipher_update(input, Some(output))
}
/// Finishes the encryption process, writing any remaining data to `output`.
///
/// The number of bytes written to `output` is returned.
///
/// `update` should not be called after this method.
///
/// # Panics
///
/// Panics if `output` is less than the cipher's block size.
pub fn finalize(&mut self, output: &mut [u8]) -> Result<usize, ErrorStack> {
self.ctx.cipher_final(output)
}
}
/// Represents an EVP_Open context.
pub struct Open {
ctx: CipherCtx,
}
impl Open {
/// Creates a new `Open`.
pub fn new<T>(
cipher: Cipher,
priv_key: &PKeyRef<T>,
iv: Option<&[u8]>,
encrypted_key: &[u8],
) -> Result<Open, ErrorStack>
where
T: HasPrivate,
{
let mut ctx = CipherCtx::new()?;
ctx.open_init(
Some(unsafe { CipherRef::from_ptr(cipher.as_ptr() as *mut _) }),
encrypted_key,
iv,
Some(priv_key),
)?;
Ok(Open { ctx })
}
/// Feeds data from `input` through the cipher, writing decrypted bytes into `output`.
///
/// The number of bytes written to `output` is returned. Note that this may
/// not be equal to the length of `input`.
///
/// # Panics
///
/// Panics if `output.len() < input.len() + block_size` where
/// `block_size` is the block size of the cipher (see `Cipher::block_size`),
/// or if `output.len() > c_int::max_value()`.
pub fn update(&mut self, input: &[u8], output: &mut [u8]) -> Result<usize, ErrorStack> {
self.ctx.cipher_update(input, Some(output))
}
/// Finishes the decryption process, writing any remaining data to `output`.
///
/// The number of bytes written to `output` is returned.
///
/// `update` should not be called after this method.
///
/// # Panics
///
/// Panics if `output` is less than the cipher's block size.
pub fn finalize(&mut self, output: &mut [u8]) -> Result<usize, ErrorStack> {
self.ctx.cipher_final(output)
}
}
#[cfg(test)]
mod test {
use super::*;
use crate::pkey::PKey;
use crate::symm::Cipher;
#[test]
fn public_encrypt_private_decrypt() {
let private_pem = include_bytes!("../test/rsa.pem");
let public_pem = include_bytes!("../test/rsa.pem.pub");
let private_key = PKey::private_key_from_pem(private_pem).unwrap();
let public_key = PKey::public_key_from_pem(public_pem).unwrap();
let cipher = Cipher::aes_256_cbc();
let secret = b"My secret message";
let mut seal = Seal::new(cipher, &[public_key]).unwrap();
let mut encrypted = vec![0; secret.len() + cipher.block_size()];
let mut enc_len = seal.update(secret, &mut encrypted).unwrap();
enc_len += seal.finalize(&mut encrypted[enc_len..]).unwrap();
let iv = seal.iv();
let encrypted_key = &seal.encrypted_keys()[0];
let mut open = Open::new(cipher, &private_key, iv, encrypted_key).unwrap();
let mut decrypted = vec![0; enc_len + cipher.block_size()];
let mut dec_len = open.update(&encrypted[..enc_len], &mut decrypted).unwrap();
dec_len += open.finalize(&mut decrypted[dec_len..]).unwrap();
assert_eq!(&secret[..], &decrypted[..dec_len]);
}
}
|
