Digital tachographs: "*.DDD" File Parsing Library

esm-parser is a Rust library and set of example CLIs for parsing digital tachograph .DDD exports. It automatically identifies the tachograph generation and data type, then returns strongly typed Rust data structures.

Project website | Website preview and publishing instructions

What it supports

• Gen1 and Gen2 tachograph data.
• Driver-card and vehicle-unit (VU) .DDD parsing.
• Parsing from a file path or an in-memory byte slice.
• JSON and XML export through the included command-line examples.
• Gen1 and Gen2 digital signature and certificate verification for both cards and vehicle units (VU).
• WebAssembly builds for browser-based parsing.

Requirements and local build

Use a current stable Rust toolchain. The project does not currently publish an MSRV policy.

git clone https://github.com/mbolaric/esm-parser.git
cd esm-parser
cargo build

Parse and verify a DDD file from Rust

The default build provides the reader API:

[dependencies]
esm-parser = "0.5.0"

Parse directly from a file:

use esm_parser::parse_from_file;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let tachograph_data = parse_from_file("card.ddd")?;
    println!("{tachograph_data:#?}");
    Ok(())
}

Or verify digital signatures across any parsed card or vehicle unit:

use esm_parser::parse_from_file;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let tachograph_data = parse_from_file("vehicle_unit.ddd")?;
    let erca_gen1_pk = std::fs::read("gen1-erca.bin")?;
    let erca_gen2_pk = std::fs::read("gen2-erca.bin")?;

    // Verify using convenience method on parsed data:
    let verify_result = tachograph_data.verify(Some(&erca_gen1_pk), Some(&erca_gen2_pk))?;
    println!("{verify_result:#?}");
    Ok(())
}

Both entry points return TachographData, which distinguishes Gen1/Gen2 and card/VU results. See the crate-level API documentation in src/lib.rs for the available data modules.

Export with the example CLIs

The examples parse a DDD file and write the selected serialization format. Passing an explicit output path is optional; when omitted, the exporter derives the path from the input file.

# JSON
cargo run --example esm2json -- \
  --ddd-file card.ddd \
  --json-file card.json \
  --pretty

# XML
cargo run --example esm2xml -- \
  --ddd-file card.ddd \
  --xml-file card.xml \
  --pretty

Use cargo run --example esm2json -- --help or cargo run --example esm2xml -- --help to see all CLI options.

Digital signature and certificate verification

The example exporters verify cards and vehicle units when the corresponding ERCA public key certificate is provided:

# Verify a Driver Card:
cargo run --example esm2json -- \
  --ddd-file card.ddd \
  --json-file card.json \
  --erca-gen1-file gen1-erca.bin \
  --erca-gen2-file gen2-erca.bin \
  --pretty

# Verify a Vehicle Unit (Gen1):
cargo run --example esm2json -- \
  --ddd-file dtco3.ddd \
  --erca-gen1-file gen1-erca.bin \
  --pretty

# Verify a Vehicle Unit (Gen2):
cargo run --example esm2json -- \
  --ddd-file dtco4.ddd \
  --erca-gen2-file gen2-erca.bin \
  --pretty

• A Gen1 ERCA value must be exactly 144 bytes (RSA-1024).
• A Gen2 ERCA CVC must be exactly 205 bytes (ECDSA brainpoolP256r1, SHA-256).
• Cards:
  • The public API verify_card verifies one generation/application map at a time.
  • CardGeneration::Combined is split into its Gen1 and Gen2 application maps (or verified via verify_combined_card).
  • For combined Driver and Workshop cards, the CLI verifies each supplied application separately and writes *_verify_gen1.* and *_verify_gen2.* results.
  • Company and Control Gen2 applications do not have a signed elementary file verification path.
• Vehicle Units (VU):
  • verify_vu_full: Verifies the certificate chain (ERCA -> MSCA -> VU_Sign) and cryptographic signatures across every downloaded TREP record (Overview, Activities, Events and Faults, Detailed Speed, and Technical Data).
  • verify_vu: Verifies the Vehicle Unit's own Overview certificate chain (ERCA -> MSCA -> VU_Sign).
  • Supports ERCA Link Certificate rollover resolution for Gen2 VU and Card verification.

Read the complete contract, certificate-chain behaviour, and fixture-test instructions in docs/gen2-signature-impl-reference.md.

WebAssembly

The parser can be compiled for browser use with wasm-pack.

cargo install wasm-pack
./scripts/build-wasm.sh
python3 -m http.server 8090

The repository build script regenerates the TypeScript contract before invoking wasm-pack build --target web. Additional wasm-pack build options can be passed through, for example ./scripts/build-wasm.sh --release.

The generated declaration is checked in at types/wasm-boundary.d.ts and is embedded into the wasm-bindgen package. The WebAssembly parser returns a discriminated { kind, data } envelope while native Rust and CLI exports retain their existing untagged output. Regenerate the declaration whenever a serialized parser type changes; the TypeScript-enabled test suite fails if the checked-in contract is stale.

Open http://127.0.0.1:8090/examples/web/ after starting the server from the repository root. Do not serve examples/web/ as the server root: the demo loads the generated package from pkg/ at the repository root.

The project demo provides a local-file WebAssembly demo with JSON preview and download. Files are parsed in the browser without uploading them; the demo does not verify signatures. See website build instructions to run it locally.

Privacy and test fixtures

DDD files can contain personal driver and vehicle data. Do not commit real production DDD files or certificate material. The fixture-backed integration tests are intentionally ignored by default so private files stay local.

Development checks

Run the standard local validation suite before submitting a change:

cargo check --all-targets
cargo test --all-targets
cargo test --all-features
cargo test --doc
cargo fmt -- --check
cargo clippy --all-targets -- -D warnings

Further reading

• Gen2 signature verification implementation reference
• Project license