num-bigint-dig

Big integer types for Rust, BigInt and BigUint.

Warning This is a fork of rust-num/num-bigint with a focus on providing functionality, needed to implement cryptographic operations.

Usage

Add this to your Cargo.toml:

[dependencies]
num-bigint-dig = "^0.7"

and this to your crate root:

extern crate num_bigint_dig as num_bigint;

Features

The std feature is enabled by default and mandatory to compile on older rust version.

It is possible to use this crate on no_std target. If you wish to compile for a target that does not have an std crate, you should use num-bigint with default-features = false. All other sub-features should be compatible with no_std. Note that in this mode, num-bigint still relies on the alloc crate, so make sure you define a global_allocator.

Implementations for i128 and u128 are only available with Rust 1.26 and later. The build script automatically detects this, but you can make it mandatory by enabling the i128 crate feature.

The u64_digit feature enables usage of larger internal “digits” (or otherwise known as “limbs”). Speeeding up almost all operations on architectures that have native support for it.

The prime feature gate enables algorithms and support for dealing with large primes.

Releases

Release notes are available in RELEASES.md.

Compatibility

The num-bigint crate is tested for rustc 1.56 and greater.

Alternatives

While num-bigint strives for good performance in pure Rust code, other crates may offer better performance with different trade-offs. The following table offers a brief comparison to a few alternatives.

Crate	License	Min rustc	Implementation
num-bigint-dig	MIT/Apache-2.0	1.56	pure rust
num-bigint	MIT/Apache-2.0	1.15	pure rust
ramp	Apache-2.0	nightly	rust and inline assembly
rug	LGPL-3.0+	1.18	bundles GMP via gmp-mpfr-sys
rust-gmp	MIT	stable?	links to GMP
apint	MIT/Apache-2.0	1.26	pure rust (unfinished)

Benchmarks

cargo bench --features prime