COMPLIANCE.md

Compliance Matrix

This document maps the application against recognized security and privacy standards. Last updated: 2026-03-12.

1. BSI TR-02102-1 (Cryptographic Mechanisms)

The German Federal Office for Information Security (BSI) publishes TR-02102-1, which specifies recommended cryptographic algorithms and key lengths.

Requirement	Status	Implementation
Approved asymmetric algorithm	PASS	ECDSA
Approved curve	PASS	secp256r1 (NIST P-256), approved through 2030+
Minimum key length	PASS	256-bit EC key (128-bit symmetric equivalent)
Approved hash function	PASS	SHA-256, SHA-512 supported
No deprecated algorithms	PASS	No MD5, SHA-1, RSA-1024, or 3DES
Hardware-backed key storage	PASS	Android KeyStore with StrongBox/TEE
Secure random number generation	PASS	Delegated to Android KeyStore (CSPRNG)

Assessment: The cryptographic implementation is fully aligned with BSI TR-02102-1 recommendations for algorithm selection and key management.

2. BSI TR-03161 (Mobile Application Security)

BSI TR-03161 defines security requirements for mobile applications in three parts.

Part 1: General Requirements

Requirement	Status	Evidence
Minimal permission usage	PASS	Only storage permissions, scoped to legacy API levels
Secure data storage	PASS	No persistent sensitive data. KeyStore for keys.
Secure communication	PASS	No network communication. Cleartext blocked.
Input validation	PASS	File size validated before processing
Secure logging	PASS	SanitizedDebugTree masks PII. No release logging.
Code obfuscation	PASS	R8/ProGuard enabled for release
Backup protection	PASS	allowBackup=false, extraction rules configured

Part 2: Android-Specific Requirements

Requirement	Status	Evidence
Target latest SDK	PASS	targetSdk 35 (Android 15)
Minimal exported components	PASS	Only MainActivity with LAUNCHER filter
No implicit intents for sensitive operations	PASS	Explicit intents for URL viewing only
Content provider security	PASS	No content providers defined
WebView security	PASS	No WebView usage
File provider security	PASS	Uses MediaStore API, no FileProvider needed

Assessment: Aligned with BSI TR-03161 requirements for mobile application security.

3. OWASP MASVS v2.0

The OWASP Mobile Application Security Verification Standard defines security requirements across seven domains.

Domain	Score	Status
MASVS-STORAGE	9/9	PASS
MASVS-CRYPTO	9/9	PASS
MASVS-AUTH	5/5	PASS
MASVS-NETWORK	5/5	PASS
MASVS-PLATFORM	5/5	PASS
MASVS-CODE	8/9	PASS
MASVS-RESILIENCE	6/9	PARTIAL

Overall: 47/51 (92%)

MASVS-RESILIENCE Details

Item	Status	Notes
Root detection	N/A	Not implemented. KeyStore integrity provides baseline protection.
Debugger detection	N/A	Not implemented. Acceptable for non-financial use case.
Emulator detection	N/A	Not implemented.
Integrity verification	PASS	Signature verification validates file integrity
Code obfuscation	PASS	ProGuard enabled
String encryption	PARTIAL	Resource strings not encrypted. Acceptable for open-source app.

4. NIST Standards

Standard	Status	Details
NIST SP 800-186 (ECC)	Aligned	P-256 curve is NIST-recommended
NIST SP 800-57 (Key Management)	Aligned	256-bit EC provides 128-bit equivalent security. Suitable through 2030+.
FIPS 186-4 (Digital Signature Standard)	Aligned	ECDSA with approved curve and hash
NIST SP 800-131A (Transitions)	Aligned	All algorithms meet current strength requirements

5. GDPR (General Data Protection Regulation)

Requirement	Status	Evidence
Data minimization	PASS	No personal data collected or processed
Purpose limitation	PASS	App purpose is file signing only
Storage limitation	PASS	Signing history is in-memory only, not persisted
Data protection by design	PASS	No network, no analytics, no telemetry
Data protection by default	PASS	Minimal permissions, backup disabled
Right to erasure	PASS	No data stored to erase (in-memory only)
Data breach notification	N/A	No data collection means no breach scenario

Assessment: Fully compliant. The application collects no personal data and makes no network connections.

6. eIDAS Regulation (EU) 910/2014

Requirement	Status	Notes
Advanced electronic signature	PARTIAL	Cryptographically linked to signatory via device KeyStore, but lacks certificate binding
Qualified electronic signature	NOT MET	Requires QTSP-issued certificate and qualified signature creation device
Timestamp token (RFC 3161)	NOT MET	No TSA integration
CAdES/XAdES/PAdES format	NOT MET	Raw ECDSA signatures used
Certificate chain	NOT MET	No X.509 certificate included with signature

Assessment: The application does not produce eIDAS-compliant electronic signatures. For EU regulatory contexts, signatures must be wrapped in a standard format (CAdES, XAdES, or PAdES) and issued through a Qualified Trust Service Provider. The underlying cryptography is sound and would be acceptable within such a wrapper.

7. Regional Compliance Summary

Region	Framework	Status
Germany	BSI TR-02102-1, TR-03161	Aligned
EU	GDPR	Compliant
EU	eIDAS	Not aligned (raw signatures)
USA	NIST SP 800-186, FIPS 186-4	Aligned
International	OWASP MASVS	92% coverage
International	ISO/IEC 27001 (cryptographic controls)	Aligned for algorithm selection and key management

8. Compliance Gaps and Remediation Path

Gap	Severity	Remediation
No eIDAS qualified signatures	Low (unless required by regulation)	Integrate with QTSP for certificate binding and CAdES wrapping
No RFC 3161 timestamps	Low	Add optional TSA integration for legal timestamp tokens
No root/debugger detection	Low	Add runtime integrity checks if threat model requires it
No key recovery mechanism	Medium	Implement encrypted key backup if device loss is a concern
Raw signature format	Low	Define and document a formal signature file format specification