rust-asn1

This is a Rust library for parsing ASN.1 data (DER only).

Installation

Add asn1 to the [dependencies] section of your Cargo.toml:

[dependencies]
asn1 = "0.3"

Builds on Rust 1.41.0 and newer. However Implicit and Explicit require const generics, which require a recent nightly or beta (1.51.0) and specifying the const-generics feature.

rust-asn1 is compatible with #![no_std] environments:

asn1 = { version = "0.3", default-features = false }

Usage

To parse a structure like:

Signature ::= SEQUENCE {
    r INTEGER,
    s INTEGER
}

you would write:

let result = asn1::parse(data, |d| {
    return d.read_element::<asn1::Sequence>()?.parse(|d| {
        let r = d.read_element::<u64>()?;
        let s = d.read_element::<u64>()?;
        return Ok((r, s));
    })
});

match result {
    Ok((r, s)) => println!("r={}, s={}", r, s),
    Err(e) => println!("Error! {:?}", e),
}

And to write that structure, you would do:

let result = asn1::write(|w| {
    w.write_element_with_type::<asn1::Sequence>(&|w: &mut asn1::Writer| {
        w.write_element(r);
        w.write_element(s);
    })
});