GoBD Compliance Report

Technical documentation of implemented security and compliance features

Core Security

Cryptographic Methods

AES-256-GCM (NIST SP 800-38D)

Authenticated Encryption with Associated Data (AEAD)

•256-bit Key Length (Quantum-resistant symmetric security)
•Galois/Counter Mode (GCM) ensuring confidentiality and authenticity
•Unique 96-bit IV/Nonce per encryption operation
•Authentication Tag validation prior to decryption (prevents Padding Oracle attacks)
•Leverages hardware acceleration (ARMv8 Cryptography Extensions)

SHA-256 (FIPS 180-4)

Cryptographic Hash Function for Data Integrity

•256-bit digest size
•Usage: HMAC generation, Key Fingerprinting, File Checksums
•Pre-image resistance and collision resistance
•Deterministic output compliant with FIPS PUB 180-4

HKDF-SHA256 (RFC 5869)

HMAC-based Extract-and-Expand Key Derivation Function

•RFC 5869 compliant key derivation
•Salt: 32-byte cryptographically secure random value
•Context binding via application-specific info strings
•Ensures cryptographic independence of session keys from master key material

Key Management

Secure System Storage

Protected key storage in operating system

•Access only when device is unlocked
•Key only available when device is unlocked
•Local storage without cloud synchronization

Cloud Key Synchronization

Optional key synchronization for multiple devices

•Secure synchronization via cloud service
•Cross-device key management
•Separate key for cloud backups

Key Fingerprint

Cryptographic hash of master key for identification

•Unique identification without key disclosure
•Enables key verification
•Stored in backup metadata

Key Identifier

Enhanced key matching for automatic cloud synchronization

•Cryptographic hash of cloud master key
•Automatic key validation during synchronization
•Prevents restoration with wrong key
•Verification before each synchronization operation

Automatic Synchronization Encryption

Automatic end-to-end encryption for cloud service

•Industry-standard encryption for all cloud data
•Key remains in protected key storage
•No unencrypted data stored in cloud
•Transparent encryption and decryption

Biometric Protection

Biometric Authentication

iOS LocalAuthentication Framework integration

•Asynchronous authentication request
•System policy evaluation for device unlock
•Protected actions: key export, data deletion
•Audit trail: logging without sensitive data

Authentication Fallback

Multi-step authentication with automatic fallback

•Primary: FaceID / TouchID
•Secondary: Device passcode
•Legacy support for older export methods
•Authentication required for critical actions

Jailbreak Detection

Comprehensive Device Integrity Check

Native implementation without external dependencies

•Check for known jailbreak URL schemes
•File system analysis for suspicious paths (40+)
•Check for readable system directories
•Sandbox integrity verification
•Symbolic link detection

Runtime Integrity Checks

Low-level system checks

•Dynamic library analysis
•Detects: known injection frameworks and debuggers
•Process isolation check
•Sandbox violation = jailbreak detected
•Immediate response on detection

Privacy Compliance

All checks local, no data transmission

•Simulator mode: checks disabled
•Mac Catalyst: separate handling
•No telemetry, no server reports
•Result only used locally for view-only mode

Data Integrity

Data Integrity & Tamper Protection

Entry-Level Checksums

Each logbook entry receives a SHA-256 checksum

•SHA-256 hash over: ID, vehicle, driver, date, locations, odometer, purpose
•ISO8601 timestamps with millisecond precision (.withFractionalSeconds)
•Pipe-separated field concatenation for deterministic calculation
•Automatic recalculation on every change

Log-Level Checksums

Each audit log entry receives its own SHA-256 checksum

•Calculated from: ID, entry reference, timestamp, change type, field changes
•Base64-encoded field changes included in checksum
•Checksum computed and stored at creation time
•Retroactive tampering detectable

HMAC-SHA256 Signatures

Backup signatures use HMAC-SHA256 (RFC 2104) instead of simple hash

•Constant-time comparison prevents timing attacks
•Legacy signature fallback for backwards compatibility
•Validation before decryption – abort on mismatch
•XOR-based byte comparison without early-exit

Immutable Change Log

Persistent Audit Trail

Every change is stored as its own entity with checksum

•Change types: created, modified, completed, deleted
•Captured data: timestamp, driver, description, checksum
•Structured field changes with before/after values
•Automatic timestamp assignment at creation

Reference Preservation on Deletion

Link is severed, audit entry remains preserved

•Log entries are not deleted when trip is deleted
•Deleted trip → Audit history remains complete
•Every deletion is captured as separate audit entry
•Complete forensic traceability

System Events

Restore operations logged with version information

•Backup restore is automatically logged
•Captures: timestamp, app version, backup version
•Automatic marking as system action
•Resource limits for memory exhaustion prevention

Deletion Timestamp

Deleted data is marked, not physically removed

•Deletion time captured on all main entities
•Entries, drivers, and vehicles with archiving function
•Historical traceability ensured

Backup Export

Deleted data is fully included in backups

•All entities including deletion status in backup structure
•Change log contains deletion operations
•Restoration with original archiving status

Timestamps & Logging

Creation & Modification Timestamps

Automatic time capture for all data operations

•Entry creation time
•Last modification time
•Trip start and end times

Standardized Time Format

Uniform time format for checksum calculation

•International standard for date and time representation
•Millisecond precision
•Deterministic representation for hash calculation

Server & Backup

Server-Side Verification & WORM Storage

Immutable WORM Storage (Switzerland)

Physically immutable data storage in Azure Switzerland North (Zurich)

•Write-Once-Read-Many (WORM) technology enforces immutability
•Legal retention policies technically enforced
•Data residency exclusively in Switzerland
•Azure Blob Storage with Time-Based Retention Policies

Server-Side Notarization

Cryptographic signature by trusted server

•Independent verification of client data before storage
•HMAC-SHA256 signature with secret server key
•Prevents retroactive manipulation even if device is compromised
•Real-time validation of App Check tokens

App Attestation & Integrity

Ensuring app authenticity via Firebase App Check

•Verification of binary integrity of the Xevono app
•Blocks requests from manipulated apps or scripts
•Protection against API abuse and fake entries
•DeviceCheck / App Attest Integration (iOS)

Server Verification & Azure Details

Backup Format

Encrypted Container

Proprietary format with version detection and integrity checking

•Magic bytes header for format identification
•Structured metadata: version, timestamp, encryption type
•Backup information: device ID, sizes, encryption mode
•Backwards compatibility with older format versions

Backup Metadata

Structured information for each backup

•Unique device identifier
•Number of backed-up logbook entries
•Size tracking: original → compressed → encrypted
•Encryption mode indicator

Processing Chain

JSON → Compression → Encryption → Checksum

•1. Serialization of logbook data
•2. zlib compression
•3. AES-256-GCM encryption with session key
•4. SHA-256 checksum over encrypted data
•5. Container packaging with header

Export & Compliance

GDPdU/GoBD Export

CSV Files

Four separate files for IDEA audit software

•fahrten.csv: All logbook entries with checksum
•fahrzeuge.csv: Vehicle master data incl. VIN
•fahrer.csv: Driver master data with address
•aenderungsprotokoll.csv: Complete audit trail

index.xml (GDPdU DTD)

Metadata description per gdpdu-01-08-2002.dtd

•DOCTYPE DataSet SYSTEM 'gdpdu-01-08-2002.dtd'
•Semicolon (;) as field delimiter
•Date format: yyyy-MM-dd, DateTime: yyyy-MM-dd HH:mm:ss
•NSFileCoordinator for atomic ZIP creation
•DataSupplier: Valeford UG (haftungsbeschränkt)

Gap Detection

Intelligent Gap Detection

Automatic detection of odometer discrepancies

•Comparison: Expected vs. actual odometer reading
•Detection at trip start and end
•User prompt for gap documentation
•Automatic generation of correction entries

Compliance Conformity

Gapless logbook management per legal requirements

•Odometer validation for each trip
•Change log for retroactive corrections
•Automatic marking of subsequent entries
•Time period bridging for gap trips

Overview

Technical Overview

Component	Method	Security Level	Technology
Encryption	Galois/Counter Mode	256 bits	CryptoKit (Apple)
Key Derivation	Hash-based (HKDF)	256 bits	CryptoKit (Apple)
Checksum Function	SHA-256 Hash	256 bits	CryptoKit (Apple)
Compression	zlib (DEFLATE)	-	zlib Library
Key Storage	Secure Enclave / Keychain	-	iOS / iPadOS