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Cryptographic Datastructures

The crypto module provides ASN.1-backed cryptographic and PKI model types built on top of awesn1 core. If you are looking for certificates, public keys, private keys, PKCS#10 requests, or common algorithm identifiers, this is the module you want.

kxs-powered starting with 0.3.0

The crypto module depends on both core and kxs. DER handling in crypto now goes through awesn1's kotlinx.serialization integration from kxs, rather than manual DER encode/decode implementations inside crypto. For the general data-class-first serialization workflow, see the Serialization Tutorial.

Why This Is Not in core

core is intentionally limited to generic ASN.1 infrastructure:

  • ASN.1 elements and rich scalar/domain types
  • DER parsing and encoding
  • tagging
  • PEM support
  • the generic ASN.1 serialization contract

Cryptographic structures sit one level above that. They are still ASN.1, but they are not universally useful building blocks in the same way as Asn1Integer, ObjectIdentifier, or Asn1Time. Keeping them in a separate module keeps core small, generic, and reusable.

This is not a full-fledged cryptography stack

The crypto module is not trying to provide:

  • Semantic validation of cryptographic structures (it does perform strict structural validations)
  • Certificate path validation
  • Signature verification policy
  • …

If you need any of those, check out Signum, which is currently being ported over to work on top of awesn1.

Maven Coordinates

implementation("at.asitplus.awesn1:crypto:$version")

Scope

At a high level, the module focuses on structural cryptographic and PKI data models rather than validation, policy enforcement, or cryptographic operations.

Cryptographic Data Structures

The module currently includes models such as:

  • SubjectPublicKeyInfo
  • Pkcs8PrivateKeyInfo
  • EncryptedPrivateKeyInfo
  • RsaPublicKeyInfo
  • Pkcs1RsaPrivateKeyInfo
  • Pkcs1RsaOtherPrimeInfo
  • Sec1EcPrivateKeyInfo
  • SignatureValue
  • X509AlgorithmIdentifier
  • RsaSsaPssParams
  • X509Certificate
  • X509TbsCertificate
  • X509CertificateExtension
  • Pkcs10CertificationRequest
  • Pkcs10CertificationRequestInfo
  • DN-related helper models such as X500RelativeDistinguishedName, X500AttributeTypeAndValue, and Attribute

These are structural models. They parse and encode ASN.1 DER correctly, but they do not aim to be a full certificate validation stack, trust engine, or cryptographic provider.

Not in Scope

The crypto module is not trying to provide:

  • certificate path validation
  • hostname verification
  • signature verification policy
  • trust store management
  • high-level JOSE/CMS/COSE stacks
  • key generation or cryptographic primitives

Those concerns are deliberately separate from the ASN.1 structural layer.

Looking for a KMP crypto provider?

Signum is currently being ported to build on top of awesn1 and provides a full Kotlin multiplatform cryptography stack. Batteries included.

Typical Use Cases

The crypto already handles the most common cryptographic data structures out of the box. It lets you:

  • Parse X.509 certificates and inspect their structure
  • Read or write PEM-Encoded public keys
  • Handle PKCS#10 certificate signing requests
  • Preserve, round-trip, or transform cryptographic ASN.1 data in Kotlin Multiplatform code
  • Use these models as strongly typed payloads in ASN.1/DER serialization workflows