Crate viadkim

A library implementing the DomainKeys Identified Mail (DKIM) specification described in RFC 6376.

This library provides both high-level APIs for signing and verifying, as well as low-level APIs that cover the various DKIM protocol areas.

The high-level API can be used to sign email messages using DKIM signatures (module signer), and to verify such signatures (module verifier). Most users will want to deal with DKIM via these APIs. For convenience, all the relevant items are re-exported at the top level.

The high-level API exposes various configuration options for both the signing and verification process. It is, however, closed, and not extensible. Instead, the low-level building blocks are provided in various additional modules. They contain basic helpers for cryptography, canonicalisation, encoding, etc. Users familiar with DKIM could use these building blocks to build their own signing and verification facilities.

Usage

The types Signer and Verifier provide the entry points to signing and verifying with viadkim.

See the examples for Signer and Verifier for basic usage.

Cargo features

The feature hickory-resolver makes an implementation of trait LookupTxt available for the Hickory DNS resolver. LookupTxt is the abstraction used for DNS resolution during verification.

The feature pre-rfc8301 reverts cryptographic algorithm and key usage back to before RFC 8301: it lowers the minimum RSA key size to 512 bits, and enables the insecure, historic SHA-1 hash algorithm. In the API and implementation, wherever there is support for the SHA-256 hash algorithm, with this feature additional support for SHA-1 becomes available. This is a legacy compatibility feature, its use is discouraged.

Trace logging

This library uses the tracing crate for internal trace logging. For insight into library operation, install a tracing subscriber and enable logging at trace level.

Re-exports

pub use crate::crypto::SigningKey;

pub use crate::header::FieldBody;

pub use crate::header::FieldName;

pub use crate::header::HeaderField;

pub use crate::header::HeaderFields;

pub use crate::signature::DomainName;

pub use crate::signature::Selector;

pub use crate::signature::SigningAlgorithm;

pub use crate::signer::sign;

pub use crate::signer::RequestError;

pub use crate::signer::SignRequest;

pub use crate::signer::Signer;

pub use crate::signer::SigningError;

pub use crate::signer::SigningOutput;

pub use crate::signer::SigningResult;

pub use crate::verifier::verify;

pub use crate::verifier::Config;

pub use crate::verifier::DkimResult;

pub use crate::verifier::VerificationError;

pub use crate::verifier::VerificationResult;

pub use crate::verifier::VerificationStatus;

pub use crate::verifier::Verifier;

Modules

canonicalize

Canonicalization utilities.

crypto

Cryptographic utilities.

header

Representation of email header data.

message_hash

Computation of the message hashes.

quoted_printable

DKIM-Quoted-Printable encoding.

record

DKIM public key record.

signature

DKIM signature.

signer

Signer and supporting types.

tag_list

Tag=value lists.

verifier

Verifier and supporting types.

Structs

Base64Error

An error that occurs when decoding Base64-encoded data.

Traits

CanonicalStr

A trait for entities that have a canonical string representation in the DKIM specification.

Functions

decode_base64

Decodes binary data from a Base64-encoded string.

encode_base64

Encodes binary data as a Base64 string.