SdJwt.Net.PresentationExchange 1.0.2

SdJwt.Net.PresentationExchange - DIF Presentation Exchange v2.1.1

Complete implementation of DIF Presentation Exchange v2.1.1 specification for intelligent credential selection and complex presentation requirements. Provides production-ready smart matching algorithms, comprehensive constraint validation, predicate-based filtering, and credential status verification with full submission requirements support.

Full DIF PE v2.1.1 Compliance + Advanced Features

This library provides 100% compliant implementation of the DIF Presentation Exchange v2.1.1 specification with all required and optional features plus advanced privacy-preserving capabilities:

Core Features

• Presentation Definitions: Complete support for presentation definition structure and validation
• Input Descriptors: Full input descriptor implementation with format constraints and field requirements
• Submission Requirements: All submission requirement patterns (all, pick) with count and range support
• Field Constraints: JSON Schema-based field filtering with JSONPath expressions
• Format Support: SD-JWT VC, JWT VC, LDP VC, and all standardized formats
• Presentation Submissions: Automatic generation of compliant presentation submissions with descriptor mappings

Advanced Privacy Features

• Predicate Filters: Zero-knowledge proof support for privacy-preserving constraints
• Age Verification: Prove age requirements without revealing exact age (age_over)
• Range Proofs: Verify values within ranges without disclosing actual values
• Set Membership: Prove membership in sets without revealing which member
• Zero-Knowledge Integration: Framework for BBS+, zk-SNARKs, and bulletproofs

Credential Status Integration

• Status List Validation: Full OAuth Status List v13 integration
• Revocation Checking: Real-time credential revocation verification
• Status Constraints: Filter credentials based on status (valid, revoked, suspended)
• Privacy-Preserving Status: Herd privacy through compressed status lists

Advanced Features

• Intelligent Selection: Smart credential matching algorithms with configurable scoring
• Selective Disclosure: Native support for SD-JWT selective disclosure requirements
• Complex Requirements: Nested submission requirements and hierarchical constraint evaluation
• JSONPath Filtering: Advanced field selection with full JSONPath expression support
• Performance Optimization: Efficient algorithms for large credential sets with timeout controls

Installation

dotnet add package SdJwt.Net.PresentationExchange

Quick Start

Define Presentation Requirements

using SdJwt.Net.PresentationExchange.Models;

// Create a presentation definition requiring employment and education verification
var presentationDefinition = new PresentationDefinition
{
    Id = "employment_and_education_verification",
    Name = "Employment and Education Verification",
    Purpose = "Verify qualifications for security clearance application",
    InputDescriptors = new[]
    {
        // University degree requirement
        InputDescriptor.CreateForSdJwt(
            "university_degree",
            "https://credentials.university.edu/degree",
            "University Degree",
            "Verify educational qualifications"),

        // Current employment requirement
        InputDescriptor.CreateWithConstraints(
            "employment_verification",
            new Constraints
            {
                Fields = new[]
                {
                    Field.CreateForValue("$.position", "Software Engineer"),
                    Field.CreateForExistence("$.security_clearance")
                }
            },
            "Current Employment",
            "Verify current employment status")
    },
    // Require both credentials to be satisfied
    SubmissionRequirements = new[]
    {
        SubmissionRequirement.CreateAll("university_degree"),
        SubmissionRequirement.CreateAll("employment_verification")
    }
};

Privacy-Preserving Predicates

Age Verification Without Revealing Exact Age

using SdJwt.Net.PresentationExchange.Models;

var ageVerificationDefinition = new PresentationDefinition
{
    Id = "age_verification_21_plus",
    Name = "Age Verification (21+)",
    Purpose = "Verify age for alcohol purchase without revealing exact age",
    InputDescriptors = new[]
    {
        new InputDescriptor
        {
            Id = "age_proof",
            Name = "Age Verification",
            Constraints = new Constraints
            {
                Fields = new[]
                {
                    // Privacy-preserving age verification
                    Field.CreateForAgeVerification(
                        minimumAge: 21,
                        agePath: "$.age",
                        useZeroKnowledge: true  // Enable ZK proof
                    )
                }
            }
        }
    }
};

Income Verification with Range Proofs

var incomeVerificationDefinition = new PresentationDefinition
{
    Id = "income_verification",
    Name = "Income Verification",
    Purpose = "Verify minimum income without revealing exact amount",
    InputDescriptors = new[]
    {
        new InputDescriptor
        {
            Id = "income_proof",
            Constraints = new Constraints
            {
                Fields = new[]
                {
                    // Privacy-preserving income verification
                    Field.CreateForIncomeVerification(
                        minimumIncome: 75000,  // Must earn at least $75k
                        useZeroKnowledge: true // Don't reveal exact salary
                    )
                }
            }
        }
    }
};

Citizenship Verification with Set Membership

var citizenshipDefinition = new PresentationDefinition
{
    Id = "citizenship_verification",
    Name = "Authorized Country Verification",
    InputDescriptors = new[]
    {
        new InputDescriptor
        {
            Id = "citizenship_proof",
            Constraints = new Constraints
            {
                Fields = new[]
                {
                    // Verify citizenship in authorized countries
                    Field.CreateForCitizenshipVerification(
                        allowedCountries: new[] { "US", "CA", "UK", "AU" },
                        citizenshipPath: "$.citizenship"
                    )
                }
            }
        }
    }
};

Credential Status Verification

Status-Aware Credential Selection

var statusAwareDefinition = new PresentationDefinition
{
    Id = "valid_credentials_only",
    Name = "Valid Credentials Required",
    Purpose = "Ensure all credentials are currently valid",
    InputDescriptors = new[]
    {
        new InputDescriptor
        {
            Id = "valid_id",
            Constraints = new Constraints
            {
                Fields = new[]
                {
                    // Require credential to have status information
                    Field.CreateForExistence("$.status"),

                    // Ensure credential is not revoked/suspended
                    Field.CreateForValue("$.status.status_list.uri",
                        "https://issuer.example.com/status/1")
                }
            }
        }
    }
};

// Engine will automatically verify status during selection
var result = await selectionEngine.SelectCredentialsAsync(
    statusAwareDefinition,
    credentials);

Credential Selection Engine

using SdJwt.Net.PresentationExchange.Engine;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

// Setup dependency injection
var services = new ServiceCollection()
    .AddLogging()
    .AddSingleton<PresentationExchangeEngine>()
    .BuildServiceProvider();

var selectionEngine = services.GetRequiredService<PresentationExchangeEngine>();

// Available credentials in wallet
var availableCredentials = new[]
{
    universityDegreeCredential,    // SD-JWT VC from Stanford
    employmentCredential,          // JWT VC from employer
    governmentIdCredential         // Additional credential
};

// Intelligent credential selection with status verification
var selectionResult = await selectionEngine.SelectCredentialsAsync(
    presentationDefinition,
    availableCredentials);

if (selectionResult.IsSuccessful)
{
    Console.WriteLine($"Selected {selectionResult.GetSelectedCount()} credentials");

    // Get the presentation submission for verifier
    var submission = selectionResult.PresentationSubmission;

    // Selected credentials with metadata
    foreach (var credential in selectionResult.SelectedCredentials)
    {
        Console.WriteLine($"Descriptor: {credential.InputDescriptorId}");
        Console.WriteLine($"Format: {credential.Format}");
        Console.WriteLine($"Match Score: {credential.MatchScore:F2}");
        Console.WriteLine($"Status: {credential.Status}"); // NEW: Status info

        // SD-JWT specific: included disclosures
        if (credential.Disclosures != null)
        {
            Console.WriteLine($"Disclosures: {credential.Disclosures.Length} items");
        }
    }
}
else
{
    Console.WriteLine("No matching credentials found:");
    foreach (var error in selectionResult.Errors)
    {
        Console.WriteLine($"- {error.Message}");
    }
}

Advanced Usage

Complex Submission Requirements

var complexDefinition = new PresentationDefinition
{
    Id = "complex_verification",
    Name = "Complex Multi-Option Verification",
    InputDescriptors = new[]
    {
        // Group A: Government ID options
        InputDescriptor.Create("passport", "Passport").WithGroup("gov_id"),
        InputDescriptor.Create("drivers_license", "Driver's License").WithGroup("gov_id"),

        // Group B: Financial verification options
        InputDescriptor.Create("bank_statement", "Bank Statement").WithGroup("financial"),
        InputDescriptor.Create("credit_report", "Credit Report").WithGroup("financial"),
        InputDescriptor.Create("employment_verification", "Employment").WithGroup("financial")
    },
    SubmissionRequirements = new[]
    {
        // Pick 1 from government ID group
        SubmissionRequirement.CreatePick("gov_id", 1, "Government ID"),

        // Pick 2 from financial group
        SubmissionRequirement.CreatePick("financial", 2, "Financial Verification")
    }
};

Field Constraints and Filtering

var constraintsDefinition = new PresentationDefinition
{
    Id = "age_and_location_verification",
    InputDescriptors = new[]
    {
        new InputDescriptor
        {
            Id = "age_verification",
            Name = "Age Verification",
            Constraints = new Constraints
            {
                Fields = new[]
                {
                    // Age must be 21 or older (privacy-preserving)
                    Field.CreateForAgeVerification(21, useZeroKnowledge: true),

                    // Must be US resident
                    Field.CreateForValue("$.address.country", "US"),

                    // Credit score range proof
                    Field.CreateForCreditScoreVerification(
                        minimumScore: 650,
                        maximumScore: 850,
                        useZeroKnowledge: true)
                },
                LimitDisclosure = "required" // Require selective disclosure support
            }
        }
    }
};

Performance Optimization

// Performance-optimized options for large wallets
var performanceOptions = CredentialSelectionOptions.CreatePerformanceOptimized();

// Thorough evaluation for critical applications
var thoroughOptions = CredentialSelectionOptions.CreateThoroughEvaluation();

// SD-JWT optimized for privacy-focused scenarios
var sdJwtOptions = CredentialSelectionOptions.CreateSdJwtOptimized();

var selectionResult = await selectionEngine.SelectCredentialsAsync(
    presentationDefinition,
    largeCredentialWallet,
    performanceOptions);

Specification Compliance

DIF Presentation Exchange v2.1.1 Features

Advanced Privacy Features

Credential Status Features

Supported Credential Formats

• SD-JWT VC (vc+sd-jwt) - Full selective disclosure support
• JWT VC (jwt_vc) - W3C Verifiable Credentials in JWT format
• JWT VP (jwt_vp) - JWT Verifiable Presentations
• LDP VC (ldp_vc) - Linked Data Proof Verifiable Credentials
• LDP VP (ldp_vp) - Linked Data Proof Presentations
• Plain JWT (jwt) - Generic JWT tokens
• ** Plain SD-JWT** (sd-jwt) - Basic selective disclosure JWTs

Real-World Use Cases

Financial Services

• Loan Applications: Multi-credential verification (employment, education, credit)
• KYC Compliance: Identity verification with selective disclosure
• Credit Assessments: Financial history with privacy-preserving range proofs

Healthcare

• Provider Credentialing: License verification with specialty constraints
• Patient Consent: Medical record sharing with field-level control
• Insurance Claims: Verification with HIPAA compliance

Government & Defense

• Security Clearance: Background verification with multiple sources
• Border Control: Age verification without revealing exact birthdate
• Service Access: Multi-factor credential requirements

Education & Professional

• Academic Verification: Degree and transcript validation
• Professional Licensing: Certification with continuing education
• Job Applications: Income verification with privacy protection

Performance & Scalability

• ** Large Wallet Support**: Efficient algorithms for 10,000+ credentials
• ** Timeout Controls**: Configurable limits for constraint evaluation
• ** Memory Optimization**: Streaming evaluation for memory efficiency
• ** Parallel Processing**: Concurrent credential evaluation
• ** Caching Support**: Smart caching for repeated evaluations
• ** Status List Caching**: Efficient credential status verification

Error Handling & Debugging

// Enable debug mode for detailed information
var debugOptions = new CredentialSelectionOptions
{
    EnableDebugMode = true,
    IncludeOptimizationHints = true
};

var result = await engine.SelectCredentialsAsync(definition, wallet, debugOptions);

// Comprehensive error information
if (!result.IsSuccessful)
{
    foreach (var error in result.Errors)
    {
        Console.WriteLine($"Error [{error.Code}]: {error.Message}");
        if (error.InputDescriptorId != null)
            Console.WriteLine($"  Descriptor: {error.InputDescriptorId}");
    }
}

// Performance metadata
var metadata = result.Metadata;
Console.WriteLine($"Evaluated {metadata.CredentialsEvaluated} credentials in {metadata.SelectionDuration}");

Documentation

For comprehensive examples and advanced patterns, see the main repository samples.

Contributing

We welcome contributions! Please see our Contributing Guide for details.

License

Licensed under the Apache License 2.0.