# num-bigint-dig
[](https://crates.io/crates/num-bigint-dig)
[](https://docs.rs/num-bigint-dig)
[](https://travis-ci.org/dignifiedquire/num-bigint)
Big integer types for Rust, `BigInt` and `BigUint`.
> **Warning** This is a fork of [`rust-num/num-bigint`](https://github.com/rust-num/num-bigint) with a focus on providing functionality, needed to implement cryptographic operations.
## Usage
Add this to your `Cargo.toml`:
```toml
[dependencies]
num-bigint-dig = ^0.4"
```
and this to your crate root:
```rust
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](RELEASES.md).
## Compatibility
The `num-bigint` crate is tested for rustc 1.36 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.
| **`num-bigint-dig`** | MIT/Apache-2.0 | 1.36 | 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) |
[`num-bigint`]: https://crates.io/crates/num-bigint
[GMP]: https://gmplib.org/
[`gmp-mpfr-sys`]: https://crates.io/crates/gmp-mpfr-sys
[`rug`]: https://crates.io/crates/rug
[`rust-gmp`]: https://crates.io/crates/rust-gmp
[`ramp`]: https://crates.io/crates/ramp
[`apint`]: https://crates.io/crates/apint
## Benchmarks
```
cargo bench --features prime
```