README.md

ZKPDF Library

A Rust library for PDF verification in zero-knowledge circuits. Provides functions for text extraction, signature verification, and GST certificate processing.

🚀 Quick Start

Installation

Add to your Cargo.toml:

[dependencies]
zkpdf-lib = { git = "https://github.com/privacy-ethereum/zkpdf", branch = "main", subdir = "circuits/lib" }

Basic Usage

use zkpdf_lib::{verify_pdf_claim, PDFCircuitInput};

// Create input for PDF verification
let input = PDFCircuitInput {
    pdf_bytes: pdf_data,
    page_number: 0,
    offset: 100,
    substring: "Important Document".to_string(),
};

// Verify PDF
let result = verify_pdf_claim(input)?;

Complete Import Example

use zkpdf_lib::{
    // Core verification functions
    verify_pdf_claim,
    verify_gst_certificate,

    // PDF processing functions
    extract_text,
    verify_text,
    verify_and_extract,
    verify_pdf_signature,

    // Data structures
    PDFCircuitInput,
    PDFCircuitOutput,
    PdfVerificationResult,
    PdfSignatureResult,
    PublicValuesStruct,
};

📋 API Reference

Core Functions

Function	Description
verify_pdf_claim(input)	Generic PDF verification with text and signature
verify_gst_certificate(input)	GST certificate specific verification
extract_text(pdf_bytes)	Extract text from PDF pages
verify_text(pdf_bytes, page, text, offset)	Verify text at specific position
verify_and_extract(pdf_bytes)	Combined signature verification and text extraction
verify_pdf_signature(pdf_bytes)	Signature-only verification

🔧 Usage Examples

Basic PDF Verification

use zkpdf_lib::{verify_pdf_claim, PDFCircuitInput};

let input = PDFCircuitInput {
    pdf_bytes: std::fs::read("document.pdf")?,
    page_number: 0,
    offset: 50,
    substring: "CONFIDENTIAL".to_string(),
};

let result = verify_pdf_claim(input)?;
println!("Text found: {}", result.substring_matches);
println!("Signature valid: {}", result.signature.is_valid);

GST Certificate Verification

use zkpdf_lib::{verify_gst_certificate, GSTCircuitInput};

let input = GSTCircuitInput {
    pdf_bytes: std::fs::read("gst-certificate.pdf")?,
};

let result = verify_gst_certificate(input)?;
println!("GST Number: {}", result.gst_number);
println!("Legal Name: {}", result.legal_name);

Text Extraction Only

use zkpdf_lib::extract_text;

let pdf_bytes = std::fs::read("document.pdf")?;
let pages = extract_text(pdf_bytes)?;

for (i, page) in pages.iter().enumerate() {
    println!("Page {}: {}", i + 1, page);
}

Signature Verification Only

use zkpdf_lib::verify_pdf_signature;

let pdf_bytes = std::fs::read("signed-document.pdf")?;
let signature_result = verify_pdf_signature(pdf_bytes)?;

if signature_result.is_valid {
    println!("Document is signed by: {}", signature_result.signer_info);
    println!("Algorithm: {}", signature_result.signature_algorithm);
}

🧪 Testing

# Run all tests
cargo test

# Run specific tests
cargo test -p zkpdf-lib

📚 Dependencies

• pdf-utils – PDF processing libraries
• alloy-primitives – Cryptographic primitives
• serde – Serialization framework
• regex – Pattern matching for text extraction

🔗 Related Crates

• pdf-utils-core – Core PDF verification logic
• pdf-utils-extractor – Text extraction from PDFs
• pdf-utils-signature-validator – Digital signature verification

📄 License

This crate is licensed under the same terms as the parent repository.