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author | Daniel Mueller <deso@posteo.net> | 2019-01-02 21:14:10 -0800 |
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committer | Daniel Mueller <deso@posteo.net> | 2019-01-02 21:14:10 -0800 |
commit | ecf3474223ca3d16a10f12dc2272e3b0ed72c1bb (patch) | |
tree | 03134a683791176b49ef5c92e8d6acd24c3b5a9b /rand/src/rngs/mod.rs | |
parent | 686f61b75055ecb02baf9d9449525ae447a3bed1 (diff) | |
download | nitrocli-ecf3474223ca3d16a10f12dc2272e3b0ed72c1bb.tar.gz nitrocli-ecf3474223ca3d16a10f12dc2272e3b0ed72c1bb.tar.bz2 |
Update nitrokey crate to 0.2.3
This change updates the nitrokey crate to version 0.2.3. This version
bumps the rand crate used to 0.6.1, which in turn requires an additional
set of dependencies.
Import subrepo nitrokey/:nitrokey at b3e2adc5bb1300441ca74cc7672617c042f3ea31
Import subrepo rand/:rand at 73613ff903512e9503e41cc8ba9eae76269dc598
Import subrepo rustc_version/:rustc_version at 0294f2ba2018bf7be672abd53db351ce5055fa02
Import subrepo semver-parser/:semver-parser at 750da9b11a04125231b1fb293866ca036845acee
Import subrepo semver/:semver at 5eb6db94fa03f4d5c64a625a56188f496be47598
Diffstat (limited to 'rand/src/rngs/mod.rs')
-rw-r--r-- | rand/src/rngs/mod.rs | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/rand/src/rngs/mod.rs b/rand/src/rngs/mod.rs new file mode 100644 index 0000000..70c4506 --- /dev/null +++ b/rand/src/rngs/mod.rs @@ -0,0 +1,217 @@ +// Copyright 2018 Developers of the Rand project. +// +// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or +// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license +// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +//! Random number generators and adapters for common usage: +//! +//! - [`ThreadRng`], a fast, secure, auto-seeded thread-local generator +//! - [`StdRng`] and [`SmallRng`], algorithms to cover typical usage +//! - [`EntropyRng`], [`OsRng`] and [`JitterRng`] as entropy sources +//! - [`mock::StepRng`] as a simple counter for tests +//! - [`adapter::ReadRng`] to read from a file/stream +//! - [`adapter::ReseedingRng`] to reseed a PRNG on clone / process fork etc. +//! +//! # Background — Random number generators (RNGs) +//! +//! Computers are inherently deterministic, so to get *random* numbers one +//! either has to use a hardware generator or collect bits of *entropy* from +//! various sources (e.g. event timestamps, or jitter). This is a relatively +//! slow and complicated operation. +//! +//! Generally the operating system will collect some entropy, remove bias, and +//! use that to seed its own PRNG; [`OsRng`] provides an interface to this. +//! [`JitterRng`] is an entropy collector included with Rand that measures +//! jitter in the CPU execution time, and jitter in memory access time. +//! [`EntropyRng`] is a wrapper that uses the best entropy source that is +//! available. +//! +//! ## Pseudo-random number generators +//! +//! What is commonly used instead of "true" random number renerators, are +//! *pseudo-random number generators* (PRNGs), deterministic algorithms that +//! produce an infinite stream of pseudo-random numbers from a small random +//! seed. PRNGs are faster, and have better provable properties. The numbers +//! produced can be statistically of very high quality and can be impossible to +//! predict. (They can also have obvious correlations and be trivial to predict; +//! quality varies.) +//! +//! There are two different types of PRNGs: those developed for simulations +//! and statistics, and those developed for use in cryptography; the latter are +//! called Cryptographically Secure PRNGs (CSPRNG or CPRNG). Both types can +//! have good statistical quality but the latter also have to be impossible to +//! predict, even after seeing many previous output values. Rand provides a good +//! default algorithm from each class: +//! +//! - [`SmallRng`] is a PRNG chosen for low memory usage, high performance and +//! good statistical quality. +//! - [`StdRng`] is a CSPRNG chosen for good performance and trust of security +//! (based on reviews, maturity and usage). The current algorithm is HC-128, +//! which is one of the recommendations by ECRYPT's eSTREAM project. +//! +//! The above PRNGs do not cover all use-cases; more algorithms can be found in +//! the [`prng` module], as well as in several other crates. For example, you +//! may wish a CSPRNG with significantly lower memory usage than [`StdRng`] +//! while being less concerned about performance, in which case [`ChaChaRng`] +//! is a good choice. +//! +//! One complexity is that the internal state of a PRNG must change with every +//! generated number. For APIs this generally means a mutable reference to the +//! state of the PRNG has to be passed around. +//! +//! A solution is [`ThreadRng`]. This is a thread-local implementation of +//! [`StdRng`] with automatic seeding on first use. It is the best choice if you +//! "just" want a convenient, secure, fast random number source. Use via the +//! [`thread_rng`] function, which gets a reference to the current thread's +//! local instance. +//! +//! ## Seeding +//! +//! As mentioned above, PRNGs require a random seed in order to produce random +//! output. This is especially important for CSPRNGs, which are still +//! deterministic algorithms, thus can only be secure if their seed value is +//! also secure. To seed a PRNG, use one of: +//! +//! - [`FromEntropy::from_entropy`]; this is the most convenient way to seed +//! with fresh, secure random data. +//! - [`SeedableRng::from_rng`]; this allows seeding from another PRNG or +//! from an entropy source such as [`EntropyRng`]. +//! - [`SeedableRng::from_seed`]; this is mostly useful if you wish to be able +//! to reproduce the output sequence by using a fixed seed. (Don't use +//! [`StdRng`] or [`SmallRng`] in this case since different algorithms may be +//! used by future versions of Rand; use an algorithm from the +//! [`prng` module].) +//! +//! ## Conclusion +//! +//! - [`thread_rng`] is what you often want to use. +//! - If you want more control, flexibility, or better performance, use +//! [`StdRng`], [`SmallRng`] or an algorithm from the [`prng` module]. +//! - Use [`FromEntropy::from_entropy`] to seed new PRNGs. +//! - If you need reproducibility, use [`SeedableRng::from_seed`] combined with +//! a named PRNG. +//! +//! More information and notes on cryptographic security can be found +//! in the [`prng` module]. +//! +//! ## Examples +//! +//! Examples of seeding PRNGs: +//! +//! ``` +//! use rand::prelude::*; +//! # use rand::Error; +//! +//! // StdRng seeded securely by the OS or local entropy collector: +//! let mut rng = StdRng::from_entropy(); +//! # let v: u32 = rng.gen(); +//! +//! // SmallRng seeded from thread_rng: +//! # fn try_inner() -> Result<(), Error> { +//! let mut rng = SmallRng::from_rng(thread_rng())?; +//! # let v: u32 = rng.gen(); +//! # Ok(()) +//! # } +//! # try_inner().unwrap(); +//! +//! // SmallRng seeded by a constant, for deterministic results: +//! let seed = [1,2,3,4, 5,6,7,8, 9,10,11,12, 13,14,15,16]; // byte array +//! let mut rng = SmallRng::from_seed(seed); +//! # let v: u32 = rng.gen(); +//! ``` +//! +//! +//! # Implementing custom RNGs +//! +//! If you want to implement custom RNG, see the [`rand_core`] crate. The RNG +//! will have to implement the [`RngCore`] trait, where the [`Rng`] trait is +//! build on top of. +//! +//! If the RNG needs seeding, also implement the [`SeedableRng`] trait. +//! +//! [`CryptoRng`] is a marker trait cryptographically secure PRNGs can +//! implement. +//! +//! +// This module: +//! [`ThreadRng`]: struct.ThreadRng.html +//! [`StdRng`]: struct.StdRng.html +//! [`SmallRng`]: struct.SmallRng.html +//! [`EntropyRng`]: struct.EntropyRng.html +//! [`OsRng`]: struct.OsRng.html +//! [`JitterRng`]: struct.JitterRng.html +// Other traits and functions: +//! [`rand_core`]: https://crates.io/crates/rand_core +//! [`prng` module]: ../prng/index.html +//! [`CryptoRng`]: ../trait.CryptoRng.html +//! [`FromEntropy`]: ../trait.FromEntropy.html +//! [`FromEntropy::from_entropy`]: ../trait.FromEntropy.html#tymethod.from_entropy +//! [`RngCore`]: ../trait.RngCore.html +//! [`Rng`]: ../trait.Rng.html +//! [`SeedableRng`]: ../trait.SeedableRng.html +//! [`SeedableRng::from_rng`]: ../trait.SeedableRng.html#tymethod.from_rng +//! [`SeedableRng::from_seed`]: ../trait.SeedableRng.html#tymethod.from_seed +//! [`thread_rng`]: ../fn.thread_rng.html +//! [`mock::StepRng`]: mock/struct.StepRng.html +//! [`adapter::ReadRng`]: adapter/struct.ReadRng.html +//! [`adapter::ReseedingRng`]: adapter/struct.ReseedingRng.html +//! [`ChaChaRng`]: ../../rand_chacha/struct.ChaChaRng.html + +pub mod adapter; + +#[cfg(feature="std")] mod entropy; +mod jitter; +pub mod mock; // Public so we don't export `StepRng` directly, making it a bit + // more clear it is intended for testing. +mod small; +mod std; +#[cfg(feature="std")] pub(crate) mod thread; + + +pub use self::jitter::{JitterRng, TimerError}; +#[cfg(feature="std")] pub use self::entropy::EntropyRng; + +pub use self::small::SmallRng; +pub use self::std::StdRng; +#[cfg(feature="std")] pub use self::thread::ThreadRng; + +#[cfg(all(feature="std", + any(target_os = "linux", target_os = "android", + target_os = "netbsd", + target_os = "dragonfly", + target_os = "haiku", + target_os = "emscripten", + target_os = "solaris", + target_os = "cloudabi", + target_os = "macos", target_os = "ios", + target_os = "freebsd", + target_os = "openbsd", target_os = "bitrig", + target_os = "redox", + target_os = "fuchsia", + windows, + all(target_arch = "wasm32", feature = "stdweb"), + all(target_arch = "wasm32", feature = "wasm-bindgen"), +)))] +mod os; + +#[cfg(all(feature="std", + any(target_os = "linux", target_os = "android", + target_os = "netbsd", + target_os = "dragonfly", + target_os = "haiku", + target_os = "emscripten", + target_os = "solaris", + target_os = "cloudabi", + target_os = "macos", target_os = "ios", + target_os = "freebsd", + target_os = "openbsd", target_os = "bitrig", + target_os = "redox", + target_os = "fuchsia", + windows, + all(target_arch = "wasm32", feature = "stdweb"), + all(target_arch = "wasm32", feature = "wasm-bindgen"), +)))] +pub use self::os::OsRng; |