openssl/
aes.rs

1//! Low level AES IGE and key wrapping functionality
2//!
3//! AES ECB, CBC, XTS, CTR, CFB, GCM and other conventional symmetric encryption
4//! modes are found in [`symm`].  This is the implementation of AES IGE and key wrapping
5//!
6//! Advanced Encryption Standard (AES) provides symmetric key cipher that
7//! the same key is used to encrypt and decrypt data.  This implementation
8//! uses 128, 192, or 256 bit keys.  This module provides functions to
9//! create a new key with [`new_encrypt`] and perform an encryption/decryption
10//! using that key with [`aes_ige`].
11//!
12//! [`new_encrypt`]: struct.AesKey.html#method.new_encrypt
13//! [`aes_ige`]: fn.aes_ige.html
14//!
15//! The [`symm`] module should be used in preference to this module in most cases.
16//! The IGE block cipher is a non-traditional cipher mode.  More traditional AES
17//! encryption methods are found in the [`Crypter`] and [`Cipher`] structs.
18//!
19//! [`symm`]: ../symm/index.html
20//! [`Crypter`]: ../symm/struct.Crypter.html
21//! [`Cipher`]: ../symm/struct.Cipher.html
22//!
23//! # Examples
24
25#![cfg_attr(
26    all(not(boringssl), not(osslconf = "OPENSSL_NO_DEPRECATED_3_0")),
27    doc = r#"\
28## AES IGE
29```rust
30use openssl::aes::{AesKey, aes_ige};
31use openssl::symm::Mode;
32
33let key = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F";
34let plaintext = b"\x12\x34\x56\x78\x90\x12\x34\x56\x12\x34\x56\x78\x90\x12\x34\x56";
35let mut iv = *b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F\
36                \x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1A\x1B\x1C\x1D\x1E\x1F";
37
38 let key = AesKey::new_encrypt(key).unwrap();
39 let mut output = [0u8; 16];
40 aes_ige(plaintext, &mut output, &key, &mut iv, Mode::Encrypt);
41 assert_eq!(output, *b"\xa6\xad\x97\x4d\x5c\xea\x1d\x36\xd2\xf3\x67\x98\x09\x07\xed\x32");
42```"#
43)]
44
45//!
46//! ## Key wrapping
47//! ```rust
48//! use openssl::aes::{AesKey, unwrap_key, wrap_key};
49//!
50//! let kek = b"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A\x0B\x0C\x0D\x0E\x0F";
51//! let key_to_wrap = b"\x00\x11\x22\x33\x44\x55\x66\x77\x88\x99\xAA\xBB\xCC\xDD\xEE\xFF";
52//!
53//! let enc_key = AesKey::new_encrypt(kek).unwrap();
54//! let mut ciphertext = [0u8; 24];
55//! wrap_key(&enc_key, None, &mut ciphertext, &key_to_wrap[..]).unwrap();
56//! let dec_key = AesKey::new_decrypt(kek).unwrap();
57//! let mut orig_key = [0u8; 16];
58//! unwrap_key(&dec_key, None, &mut orig_key, &ciphertext[..]).unwrap();
59//!
60//! assert_eq!(&orig_key[..], &key_to_wrap[..]);
61//! ```
62//!
63use cfg_if::cfg_if;
64use libc::{c_int, c_uint};
65use std::mem::MaybeUninit;
66use std::ptr;
67
68#[cfg(not(boringssl))]
69use crate::symm::Mode;
70use openssl_macros::corresponds;
71
72/// Provides Error handling for parsing keys.
73#[derive(Debug)]
74pub struct KeyError(());
75
76/// The key used to encrypt or decrypt cipher blocks.
77pub struct AesKey(ffi::AES_KEY);
78
79cfg_if! {
80    if #[cfg(boringssl)] {
81        type AesBitType = c_uint;
82        type AesSizeType = usize;
83    } else {
84        type AesBitType = c_int;
85        type AesSizeType = c_uint;
86    }
87}
88
89impl AesKey {
90    /// Prepares a key for encryption.
91    ///
92    /// # Failure
93    ///
94    /// Returns an error if the key is not 128, 192, or 256 bits.
95    #[corresponds(AES_set_encrypt_key)]
96    pub fn new_encrypt(key: &[u8]) -> Result<AesKey, KeyError> {
97        unsafe {
98            assert!(key.len() <= c_int::MAX as usize / 8);
99
100            let mut aes_key = MaybeUninit::uninit();
101            let r = ffi::AES_set_encrypt_key(
102                key.as_ptr() as *const _,
103                key.len() as AesBitType * 8,
104                aes_key.as_mut_ptr(),
105            );
106            if r == 0 {
107                Ok(AesKey(aes_key.assume_init()))
108            } else {
109                Err(KeyError(()))
110            }
111        }
112    }
113
114    /// Prepares a key for decryption.
115    ///
116    /// # Failure
117    ///
118    /// Returns an error if the key is not 128, 192, or 256 bits.
119    #[corresponds(AES_set_decrypt_key)]
120    pub fn new_decrypt(key: &[u8]) -> Result<AesKey, KeyError> {
121        unsafe {
122            assert!(key.len() <= c_int::MAX as usize / 8);
123
124            let mut aes_key = MaybeUninit::uninit();
125            let r = ffi::AES_set_decrypt_key(
126                key.as_ptr() as *const _,
127                key.len() as AesBitType * 8,
128                aes_key.as_mut_ptr(),
129            );
130
131            if r == 0 {
132                Ok(AesKey(aes_key.assume_init()))
133            } else {
134                Err(KeyError(()))
135            }
136        }
137    }
138}
139
140/// Performs AES IGE encryption or decryption
141///
142/// AES IGE (Infinite Garble Extension) is a form of AES block cipher utilized in
143/// OpenSSL.  Infinite Garble refers to propagating forward errors.  IGE, like other
144/// block ciphers implemented for AES requires an initialization vector.  The IGE mode
145/// allows a stream of blocks to be encrypted or decrypted without having the entire
146/// plaintext available.  For more information, visit [AES IGE Encryption].
147///
148/// This block cipher uses 16 byte blocks.  The rust implementation will panic
149/// if the input or output does not meet this 16-byte boundary.  Attention must
150/// be made in this low level implementation to pad the value to the 128-bit boundary.
151///
152/// [AES IGE Encryption]: http://www.links.org/files/openssl-ige.pdf
153///
154/// # Panics
155///
156/// Panics if `in_` is not the same length as `out`, if that length is not a multiple of 16, or if
157/// `iv` is not at least 32 bytes.
158#[cfg(not(boringssl))]
159#[cfg(not(osslconf = "OPENSSL_NO_DEPRECATED_3_0"))]
160#[corresponds(AES_ige_encrypt)]
161pub fn aes_ige(in_: &[u8], out: &mut [u8], key: &AesKey, iv: &mut [u8], mode: Mode) {
162    unsafe {
163        assert!(in_.len() == out.len());
164        assert!(in_.len() % ffi::AES_BLOCK_SIZE as usize == 0);
165        assert!(iv.len() >= ffi::AES_BLOCK_SIZE as usize * 2);
166
167        let mode = match mode {
168            Mode::Encrypt => ffi::AES_ENCRYPT,
169            Mode::Decrypt => ffi::AES_DECRYPT,
170        };
171        ffi::AES_ige_encrypt(
172            in_.as_ptr() as *const _,
173            out.as_mut_ptr() as *mut _,
174            in_.len(),
175            &key.0,
176            iv.as_mut_ptr() as *mut _,
177            mode,
178        );
179    }
180}
181
182/// Wrap a key, according to [RFC 3394](https://tools.ietf.org/html/rfc3394)
183///
184/// * `key`: The key-encrypting-key to use. Must be a encrypting key
185/// * `iv`: The IV to use. You must use the same IV for both wrapping and unwrapping
186/// * `out`: The output buffer to store the ciphertext
187/// * `in_`: The input buffer, storing the key to be wrapped
188///
189/// Returns the number of bytes written into `out`
190///
191/// # Panics
192///
193/// Panics if either `out` or `in_` do not have sizes that are a multiple of 8, or if
194/// `out` is not 8 bytes longer than `in_`
195#[corresponds(AES_wrap_key)]
196pub fn wrap_key(
197    key: &AesKey,
198    iv: Option<[u8; 8]>,
199    out: &mut [u8],
200    in_: &[u8],
201) -> Result<usize, KeyError> {
202    unsafe {
203        assert!(out.len() >= in_.len() + 8); // Ciphertext is 64 bits longer (see 2.2.1)
204
205        let written = ffi::AES_wrap_key(
206            &key.0 as *const _ as *mut _, // this is safe, the implementation only uses the key as a const pointer.
207            iv.as_ref()
208                .map_or(ptr::null(), |iv| iv.as_ptr() as *const _),
209            out.as_ptr() as *mut _,
210            in_.as_ptr() as *const _,
211            in_.len() as AesSizeType,
212        );
213        if written <= 0 {
214            Err(KeyError(()))
215        } else {
216            Ok(written as usize)
217        }
218    }
219}
220
221/// Unwrap a key, according to [RFC 3394](https://tools.ietf.org/html/rfc3394)
222///
223/// * `key`: The key-encrypting-key to decrypt the wrapped key. Must be a decrypting key
224/// * `iv`: The same IV used for wrapping the key
225/// * `out`: The buffer to write the unwrapped key to
226/// * `in_`: The input ciphertext
227///
228/// Returns the number of bytes written into `out`
229///
230/// # Panics
231///
232/// Panics if either `out` or `in_` do not have sizes that are a multiple of 8, or
233/// if `in_` is not 8 bytes longer than `out`
234#[corresponds(AES_unwrap_key)]
235pub fn unwrap_key(
236    key: &AesKey,
237    iv: Option<[u8; 8]>,
238    out: &mut [u8],
239    in_: &[u8],
240) -> Result<usize, KeyError> {
241    unsafe {
242        assert!(out.len() + 8 <= in_.len());
243
244        let written = ffi::AES_unwrap_key(
245            &key.0 as *const _ as *mut _, // this is safe, the implementation only uses the key as a const pointer.
246            iv.as_ref()
247                .map_or(ptr::null(), |iv| iv.as_ptr() as *const _),
248            out.as_ptr() as *mut _,
249            in_.as_ptr() as *const _,
250            in_.len() as AesSizeType,
251        );
252
253        if written <= 0 {
254            Err(KeyError(()))
255        } else {
256            Ok(written as usize)
257        }
258    }
259}
260
261#[cfg(test)]
262mod test {
263    use hex::FromHex;
264
265    use super::*;
266    #[cfg(not(boringssl))]
267    use crate::symm::Mode;
268
269    // From https://www.mgp25.com/AESIGE/
270    #[test]
271    #[cfg(not(boringssl))]
272    #[cfg(not(osslconf = "OPENSSL_NO_DEPRECATED_3_0"))]
273    fn ige_vector_1() {
274        let raw_key = "000102030405060708090A0B0C0D0E0F";
275        let raw_iv = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F";
276        let raw_pt = "0000000000000000000000000000000000000000000000000000000000000000";
277        let raw_ct = "1A8519A6557BE652E9DA8E43DA4EF4453CF456B4CA488AA383C79C98B34797CB";
278
279        let key = AesKey::new_encrypt(&Vec::from_hex(raw_key).unwrap()).unwrap();
280        let mut iv = Vec::from_hex(raw_iv).unwrap();
281        let pt = Vec::from_hex(raw_pt).unwrap();
282        let ct = Vec::from_hex(raw_ct).unwrap();
283
284        let mut ct_actual = vec![0; ct.len()];
285        aes_ige(&pt, &mut ct_actual, &key, &mut iv, Mode::Encrypt);
286        assert_eq!(ct_actual, ct);
287
288        let key = AesKey::new_decrypt(&Vec::from_hex(raw_key).unwrap()).unwrap();
289        let mut iv = Vec::from_hex(raw_iv).unwrap();
290        let mut pt_actual = vec![0; pt.len()];
291        aes_ige(&ct, &mut pt_actual, &key, &mut iv, Mode::Decrypt);
292        assert_eq!(pt_actual, pt);
293    }
294
295    // from the RFC https://tools.ietf.org/html/rfc3394#section-2.2.3
296    #[test]
297    fn test_wrap_unwrap() {
298        let raw_key = Vec::from_hex("000102030405060708090A0B0C0D0E0F").unwrap();
299        let key_data = Vec::from_hex("00112233445566778899AABBCCDDEEFF").unwrap();
300        let expected_ciphertext =
301            Vec::from_hex("1FA68B0A8112B447AEF34BD8FB5A7B829D3E862371D2CFE5").unwrap();
302
303        let enc_key = AesKey::new_encrypt(&raw_key).unwrap();
304        let mut wrapped = [0; 24];
305        assert_eq!(
306            wrap_key(&enc_key, None, &mut wrapped, &key_data).unwrap(),
307            24
308        );
309        assert_eq!(&wrapped[..], &expected_ciphertext[..]);
310
311        let dec_key = AesKey::new_decrypt(&raw_key).unwrap();
312        let mut unwrapped = [0; 16];
313        assert_eq!(
314            unwrap_key(&dec_key, None, &mut unwrapped, &wrapped).unwrap(),
315            16
316        );
317        assert_eq!(&unwrapped[..], &key_data[..]);
318    }
319}
openssl/aes.rs

openssl/
aes.rs
