Verifiable

An integrated .NET stack for decentralized identity: DIDs, verifiable credentials, selective disclosure, and hardware-backed cryptography.

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What is Verifiable?

Verifiable is a comprehensive .NET library implementing the W3C Decentralized Identifiers and Verifiable Credentials specifications, along with associated protocols from the Decentralized Identity Foundation and the OpenID Foundation. The library provides an integrated stack where cryptographic primitives, serialization, credential management, and hardware security work together cohesively.

The core value proposition is documents that can be distinctly identified, cryptographically signed, linked, timestamped, and selectively disclosed without requiring a central governing party while remaining compatible with regulated ecosystems like eIDAS.

Libraries

Library	Purpose	NuGet
Verifiable	CLI tool for library functionality
Verifiable.Core	DIDs, verifiable credentials, and data integrity proofs
Verifiable.Cryptography	Cryptographic primitives: salt generation, memory-safe key handling, hash functions
Verifiable.JCose	JOSE and COSE structures including SD-JWT and selective disclosure
Verifiable.OAuth	OAuth 2.0 / OpenID protocol flows: OpenID4VCI, OpenID4VP, HAIP, SIOPv2, OpenID Federation, Shared Signals, AuthZEN
Verifiable.Json	JSON serialization converters
Verifiable.Cbor	CBOR serialization for COSE envelopes
Verifiable.BouncyCastle	Cross-platform cryptography via BouncyCastle
Verifiable.NSec	High-performance cryptography via NSec
Verifiable.Microsoft	.NET standard cryptographic functions
Verifiable.Tpm	Trusted Platform Module integration
Verifiable.Sidetree	Sidetree protocol implementation
Verifiable.Jwt	JWT integration
Verifiable.Security.DataStorage	Secure storage utilities

Key capabilities

Decentralized identifiers and credentials. Full implementation of the W3C DID Core and Verifiable Credentials Data Model 2.0 specifications, including data integrity proofs with EdDSA-RDFC-2022, EdDSA-JCS-2022, and ECDSA-SD-2023 cryptosuites.

Selective disclosure. Support for privacy-preserving credential presentation through SD-JWT (RFC 9901), ECDSA-SD-2023 for JSON-LD credentials, and SD-CWT. Wallet operations include minimum disclosure computation, maximum disclosure bounds, and optimal selection algorithms.

Protocol flows. Issuer, verifier, and wallet implementations of OpenID for Verifiable Credential Issuance, OpenID for Verifiable Presentations and the high-assurance interoperability profile, Self-Issued OpenID Provider v2, OAuth 2.0 / OpenID Connect, OpenID Federation, and Shared Signals. See Implemented flows.

Multiple cryptographic backends. Delegate-based architecture allows plugging in BouncyCastle for cross-platform support, NSec for high performance, .NET cryptographic functions, or hardware security modules.

Hardware security. TPM 2.0 integration for hardware-backed key storage, PCR reading, event log parsing, attestations, and other TPM functionality to come. The architecture extends to HSMs and cloud KMS services through the delegate pattern.

Serialization flexibility. Core types remain agnostic to serialization format. JSON support via System.Text.Json and CBOR support via System.Formats.Cbor are provided in separate packages, enabling the same credential logic to work across both formats or any other.

Memory-safe key handling. Sensitive cryptographic material is ring-fenced using dedicated types with support for custom memory allocation through MemoryPool<T>, enabling scenarios like mlocked memory regions.

Architecture principles

The library follows data-oriented programming principles where code is separate from immutable data, favoring generic data structures and general-purpose functions implemented as extension methods. Domain types contain raw cryptographic material without encoding artifacts, with encoding handled at serialization boundaries.

Cryptographic operations use a delegate-based extensibility model rather than direct implementations. This allows the same high-level API to work with software keys, TPM-backed keys, HSM keys, or cloud KMS without changing calling code. The SensitiveMemoryPool provides exact-size memory allocation for cryptographic material.

The three-party credential flow (Issuer → Holder → Verifier) is modeled explicitly, with clear separation between what each party knows and computes. Internal computation state is not passed between parties; instead, each party derives what it needs from the credential and proof structures.

Implemented flows

The library includes the following protocol flows, each with tests. The test suite is the authoritative list.

• Credential issuance (OpenID4VCI 1.0) — issuer and wallet sides: authorization code and pre-authorized code grants, credential offers (by value and by reference), the credential, deferred, notification, and nonce endpoints, issuer metadata, request and response encryption, holder-binding proof validation (jwt, attestation, and di_vp proof types), key attestations, and DPoP-bound credential access tokens.
• Credential presentation (OpenID4VP 1.0) — verifier and wallet sides, for cross-device, same-device, and same-device app-to-app interactions. Supports the OpenID4VP client identifier schemes, both direct_post and encrypted direct_post.jwt responses, and DCQL credential queries.
• Self-issued identity (SIOPv2 1.0) — the relying-party flow with signed request objects served at request_uri, encrypted and combined id_token + vp_token responses, and nonce-replay defense, plus OP-side request validation, provider metadata, and self-issued ID token minting.
• High-assurance profile (HAIP 1.0) — the OpenID4VP profile used by EUDI-style deployments: encrypted responses and X.509-based request signing.
• Credential formats in presentation — SD-JWT VC, ISO mdoc (ISO/IEC 18013-5), and SD-CWT, with holder key binding and selective disclosure.
• Verifiable credential data integrity — issuing and verifying credentials with W3C Data Integrity proofs: EdDSA-RDFC-2022, EdDSA-JCS-2022, and ECDSA-SD-2023.
• OAuth 2.0 / OpenID Connect — authorization code with PKCE, pushed authorization requests, signed request objects, DPoP, rich authorization requests with a per-type handler registry, JWT-secured authorization responses, token introspection with JWT responses, token refresh and revocation, dynamic client registration, and server and protected-resource metadata, including the FAPI 2.0 security profile and message signing constraints.
• OpenID Federation 1.0 — entity configurations, trust chain resolution, metadata policy, trust marks, and client registration.
• Shared Signals (SSF, CAEP, RISC) — transmitter and receiver, with push and poll delivery and stream management.
• AuthZEN — access evaluation, single and batch.

Getting started

Install the packages relevant to your use case:

# Core functionality
dotnet add package Verifiable.Core

# For JSON serialization
dotnet add package Verifiable.Json

# For OAuth / OpenID protocol flows (OpenID4VP, Federation, and others)
dotnet add package Verifiable.OAuth

# For BouncyCastle cryptography (cross-platform)
dotnet add package Verifiable.BouncyCastle

# For TPM integration
dotnet add package Verifiable.Tpm

Development

The codebase runs on Windows, Linux, and macOS. Some hardware-specific functionality such as TPM operations may only work on certain platforms.

Press . on the repository page to open the codebase in VS Code web editor for quick exploration.

Vulnerability disclosure

For secure disclosure of security vulnerabilities, please see the security policy.

Contributing

Please read the contribution guidelines for technical details.

The TPM.DEV community provides excellent TPM-related study materials and discussions.

Ways to contribute

• Open issues for bugs, suggestions, or improvements.
• Create pull requests following the contribution guidelines.
• Add tests, especially those using test vectors from other implementations for cross-checking.
• Expand TPM functionality including signing, encryption, and permissions.
• Add more cryptographic and security capabilities.
• Support additional protocols from the Decentralized Identity Foundation.
• Improve threat and privacy modeling using frameworks like LINDDUN.

License

See the LICENSE file for details.

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Note: This is an early version under active development. APIs may change between versions.