1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147

//! This crate implements the PBKDF2 key derivation function as specified
//! in [RFC 2898](https://tools.ietf.org/html/rfc2898).
//!
//! If you are only using the low-level [`pbkdf2`] function instead of the
//! higher-level [`Pbkdf2`] struct to produce/verify hash strings,
//! it's recommended to disable default features in your `Cargo.toml`:
//!
//! ```toml
//! [dependencies]
//! pbkdf2 = { version = "0.11", default-features = false }
//! ```
//!
//! # Usage (simple with default params)
//!
//! Note: this example requires the `rand_core` crate with the `std` feature
//! enabled for `rand_core::OsRng` (embedded platforms can substitute their
//! own RNG)
//!
//! Add the following to your crate's `Cargo.toml` to import it:
//!
//! ```toml
//! [dependencies]
//! pbkdf2 = "0.10"
//! rand_core = { version = "0.6", features = ["std"] }
//! ```
//!
//! The following example demonstrates the high-level password hashing API:
//!
//! ```
//! # fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # #[cfg(all(feature = "simple", feature = "std"))]
//! # {
//! use pbkdf2::{
//!     password_hash::{
//!         rand_core::OsRng,
//!         PasswordHash, PasswordHasher, PasswordVerifier, SaltString
//!     },
//!     Pbkdf2
//! };
//!
//! let password = b"hunter42"; // Bad password; don't actually use!
//! let salt = SaltString::generate(&mut OsRng);
//!
//! // Hash password to PHC string ($pbkdf2-sha256$...)
//! let password_hash = Pbkdf2.hash_password(password, &salt)?.to_string();
//!
//! // Verify password against PHC string
//! let parsed_hash = PasswordHash::new(&password_hash)?;
//! assert!(Pbkdf2.verify_password(password, &parsed_hash).is_ok());
//! # }
//! # Ok(())
//! # }
//! ```

#![no_std]
#![cfg_attr(docsrs, feature(doc_cfg))]
#![doc(
    html_logo_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg",
    html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/media/8f1a9894/logo.svg"
)]

#[cfg(feature = "std")]
extern crate std;

#[cfg(feature = "simple")]
extern crate alloc;

#[cfg(feature = "simple")]
#[cfg_attr(docsrs, doc(cfg(feature = "simple")))]
pub use password_hash;

#[cfg(feature = "simple")]
mod simple;

#[cfg(feature = "simple")]
pub use crate::simple::{Algorithm, Params, Pbkdf2};

#[cfg(feature = "parallel")]
use rayon::prelude::*;

use digest::{generic_array::typenum::Unsigned, FixedOutput, KeyInit, Update};

#[inline(always)]
fn xor(res: &mut [u8], salt: &[u8]) {
    debug_assert!(salt.len() >= res.len(), "length mismatch in xor");
    res.iter_mut().zip(salt.iter()).for_each(|(a, b)| *a ^= b);
}

#[inline(always)]
fn pbkdf2_body<PRF>(i: u32, chunk: &mut [u8], prf: &PRF, salt: &[u8], rounds: u32)
where
    PRF: KeyInit + Update + FixedOutput + Clone,
{
    for v in chunk.iter_mut() {
        *v = 0;
    }

    let mut salt = {
        let mut prfc = prf.clone();
        prfc.update(salt);
        prfc.update(&(i + 1).to_be_bytes());

        let salt = prfc.finalize_fixed();
        xor(chunk, &salt);
        salt
    };

    for _ in 1..rounds {
        let mut prfc = prf.clone();
        prfc.update(&salt);
        salt = prfc.finalize_fixed();

        xor(chunk, &salt);
    }
}

/// Generic implementation of PBKDF2 algorithm.
#[cfg(not(feature = "parallel"))]
#[inline]
pub fn pbkdf2<PRF>(password: &[u8], salt: &[u8], rounds: u32, res: &mut [u8])
where
    PRF: KeyInit + Update + FixedOutput + Clone + Sync,
{
    let n = PRF::OutputSize::to_usize();
    // note: HMAC can be initialized with keys of any size,
    // so this panic never happens with it
    let prf = PRF::new_from_slice(password).expect("PRF initialization failure");

    for (i, chunk) in res.chunks_mut(n).enumerate() {
        pbkdf2_body(i as u32, chunk, &prf, salt, rounds);
    }
}

/// Generic implementation of PBKDF2 algorithm.
#[cfg(feature = "parallel")]
#[inline]
pub fn pbkdf2<PRF>(password: &[u8], salt: &[u8], rounds: u32, res: &mut [u8])
where
    PRF: KeyInit + Update + FixedOutput + Clone + Sync,
{
    let n = PRF::OutputSize::to_usize();
    let prf = PRF::new_from_slice(password).expect("PRF initialization failure");

    res.par_chunks_mut(n).enumerate().for_each(|(i, chunk)| {
        pbkdf2_body(i as u32, chunk, &prf, salt, rounds);
    });
}