csca masterlist tools — Easily parse ICAO/BSI CSCA…

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About this project

CSCA Master List Tools simplifies the extraction of Country Signing CA certificates from ICAO/BSI Master Lists (.ml). With just one command and minimal dependencies, it allows users to produce PEM bundles and TSV manifests, even recovering certificates that failed to parse in strict mode. Streamline your workflow with this essential tool for electronic passport validation.

The csca-masterlist-tools repository provides a straightforward utility for parsing an ICAO/BSI CSCA Master List (.ml) file to extract and export every Country Signing CA (CSCA) certificate. This project facilitates the creation of a PEM bundle, a TSV manifest, and provides an OpenSSL fallback for certificates that strict ASN.1 parsers might reject, enabling comprehensive handling of CSCA data.

Key Features

Simple Operation: Use a single command with one dependency to get certificates from a Master List file, making it user-friendly and efficient.
```
python extract_masterlist.py DE_ML_2026-01-08.ml -o csca_bundle.pem -m manifest.tsv
```
Detailed Parsing Statistics: The tool details the parsing process, allowing users to verify the number of entries, unique certificates, and any failures through a clear output format. For example:
```
master list : DE_ML_2026-01-08.ml (891,227 bytes)
entries     : 581
parsed      : 581   (openssl fallback rescued 6)
unparsable  : 0
unique      : 581
countries   : 112
```
Robust Certificate Handling: In cases where certain entries cannot be parsed using the standard library, the tool defaults to OpenSSL, ensuring all valid certificates are recovered. An example of the parsing discrepancies is provided:

# Subject
48, 49 C=AT, O=GV, OU=BMI, CN=CSCA-AUSTRIA
61 C=AE, O=MOI, OU=EPASS, CN=UAE CSCA 02
84, 85, 90 C=JP, O=Japanese Government, ...
Flexible Output Options: The tool allows users to specify output formats, such as generating a concatenated PEM trust bundle or a detailed TSV manifest for each certificate.

#	Subject
48, 49	`C=AT, O=GV, OU=BMI, CN=CSCA-AUSTRIA`
61	`C=AE, O=MOI, OU=EPASS, CN=UAE CSCA 02`
84, 85, 90	`C=JP, O=Japanese Government, ...`

Practical Use Cases

The csca-masterlist-tools is dedicated to efficiently handling public trust anchors associated with electronic passports. This tool is particularly useful in validating SODs (Security Object Data) on eMRTDs (electronic Machine Readable Travel Documents), where states publish their CSCAs for public access. It avoids the complexity of larger verification systems, focusing instead on straightforward file parsing and certificate extraction.

Usage Example

For straightforward usage, simply run the script with relevant flags:

extract_masterlist.py MASTERLIST [-o BUNDLE.pem] [-m MANIFEST.tsv] [--keep-duplicates] [--strict]

-o, --out: Specify output for a PEM trust bundle.
-m, --manifest: Generate a TSV manifest of certificate details.
--strict: Execute without OpenSSL fallback if desired.

This project is built for those who require a reliable method to handle CSCA certificates from a Master List while ensuring that all valid certificates are accessible.