rust-asn1

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

Installation

Add asn1 to your Cargo.toml:

$ cargo add asn1

Builds on Rust 1.83.0 and newer.

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

$ cargo add asn1 --no-default-features

Changelog

Unreleased

[0.24.1]

Added

• Added Tlv::tag_bytes() which returns the DER-encoded bytes of the tag portion of a TLV. (#608)

Fixes

• Fixed encoding a Set with absent optional fields incorrectly returning InvalidSetOrdering. (#607)

[0.24.0]

Added

• Added Set, SetWriter, and SetElementWriter types for parsing and writing ASN.1 SET values with DER ordering validation. (#600)
• Added an associated error type to the Asn1Writable, SimpleAsn1Writable and Asn1DefinedByWritable traits. Types implementing these traits can now return a custom error type during serialization, as long as the error type is convertible to WriteError. (#597)
• Added BigInt::bit_length() and OwnedBigInt::bit_length() which return the number of significant bits in the integer's magnitude (absolute value). (#603)
• Added ObjectIdentifier::as_der(). (#598)

Changes

• SequenceWriter is now generic over the error type, which defaults to WriteError. (#601)

Removed

• Tag::write_to has been removed from the public API. (#604)

[0.23.1]

Added

• Tag now exposes a write_to method that writes the tag's encoded representation to a WriteBuf.

[0.23.0]

Added

• Writer now exposes write_explicit_element and write_implicit_element methods that allow encoding EXPLICIT/IMPLICIT elements when the tag number is not known at compile time.

• NonZero numbers now implement Asn1Writable.

Changes

• Updated MSRV to 1.83.0.

[0.22.0]

Added

• Added Asn1Writable::encoded_length, SimpleAsn1Writable::data_length, and Asn1DefinedByWritable::encoded_length. Implementing these functions reduces the number of re-allocations required when writing. None can be returned if it is not possible to provide an efficient implementation.

Changes

• Updated MSRV to 1.74.0.

[0.21.3]

Added

• BitString::new is now const fn.

[0.21.2]

Added

• BigInt::new, BigUint::new, and DateTime::new are now const fn.

[0.21.1]

Added

• Parser now exposes a peek_tag method that returns the tag of the next element in the parse, without consuming that element. (#532)
• Parser now exposes read_explicit_element and read_implicit_element methods that allow parsing EXPLICIT/IMPLICIT elements when the tag number is not known at compile time.
• PrintableString, Utf8String, BMPString, and UniversalString now #[derive(Hash)]. (#536)

[0.21.0]

Changes

• Updated MSRV to 1.65.0.

Fixes

• Fixed "perfect derives" in conjunction with #[derive(Asn1DefinedByRead)] and #[derive(Asn1DefinedByWrite)]. (#506)

[0.20.0]

🚨 Breaking changes

• Removed Writer::{write_explicit_element, write_optional_explicit_element, write_implicit_element, write_optional_implicit_element}. These can all be better accomplished with the asn1::Explicit and asn1::Implicit types.

Fixes

• Fixed "perfect derives" in conjunction with #[implicit] and #[explicit]. (#502)

[0.19.0]

🚨 Breaking changes

• GeneralizedTime has been renamed to X509GeneralizedTime. The type does not allow fractional seconds, however this restriction is not actually a DER rule, it is specific to X.509. (#494)

• GeneralizedTime is a new type that accepts fractional seconds replacing the old GeneralizedTime. (#492)

• #[derive(asn1::Asn1Read)] and #[derive(asn1::Asn1Write)] now implement "perfect derives". (#496)