AFT3CH v1.0.2 is a fully HIPAA-compliant Windows desktop application for viewing and processing physiological signals from BIOPAC systems. It implements comprehensive security controls meeting all technical safeguards under 45 CFR §164.312.
The application runs as a standard user-mode .NET desktop application without installing services, kernel drivers, or modifying firewall rules. All PHI is protected with AES-256 encryption, and comprehensive audit logging tracks all operations for 6-year HIPAA retention requirements.
HIPAA Encryption & Data Protection
AFT3CH v1.0.2 implements comprehensive encryption for all Protected Health Information (PHI), ensuring data remains secure from creation through disposal.
PDF Encryption (PdfEncryptionService)
AES-256 Document Encryption
All PDF runsheets encrypted using AES-256 via the iText library. Dual password system with separate owner and user passwords for granular access control.
Permission Levels
Restricted (Default): No printing/copying/modification for HIPAA compliance.
ReadOnly: View and print only.
Standard: View, print, and copy.
Full: All permissions granted.
JSON Header Encryption (FileEncryptionService)
- AES-256-GCM: Authenticated encryption providing both confidentiality and tamper detection
- Metadata Protection: Nonce, authentication tag, and original filename stored in structured format
- Integrity Verification: GCM tag validates file integrity on every decryption
Password Vault (PasswordVaultService)
Master Password Security
Format: Orbital passphrase (e.g., saturn-bright-comet-4829)
Key Derivation: PBKDF2-SHA256 with 600,000 iterations
Storage: Windows DPAPI via SecureKeyManager
Vault Features
MFA Protection: Optional multi-factor authentication
Auto-Backup: Maintains 10 most recent vault backups
System Operations: MFA bypassed for automated runsheet generation
Secure Package Export (SecurePackageExporter)
- Tamper-Evident ZIP: Encrypted PDF, encrypted JSON header, password manifest
- SHA-256 Integrity: Hash verification for all package contents
- Human-Readable Passwords: Uppercase + digits with dashes (e.g., A7K2-M9P4-X3N8)
HIPAA Reference: These encryption controls satisfy 45 CFR §164.312(a)(2)(iv) Encryption, §164.312(c)(1) Integrity, and §164.312(e)(2)(ii) Transmission Security requirements.
HIPAA Audit Logging
The HipaaAuditLogger tracks all PHI-related operations to support the 6-year HIPAA data retention requirement and incident investigation.
Logged Operations
- File Encryption/Decryption: Timestamp, file identifier, method, user context
- Vault Access: Operation type, MFA status, success/failure
- Password Operations: Credential type, create/retrieve/delete actions
- Export Operations: Package identifier, recipient info, hash values
Data Integrity: Atomic file operations (temp files + atomic replace) prevent data corruption during write operations.
Network Data Transfer (NDT)
AFT3CH communicates with AcqKnowledge using BIOPAC's documented NDT mechanism, where AcqKnowledge acts as the server and AFT3CH as the client.
Connection Types
- Control Connection: AFT3CH → AcqKnowledge for channel configuration, sampling rates, and acquisition control via documented NDT commands
- Data Connections: AcqKnowledge → AFT3CH carrying physiological data streams (ECG, EMG, respiration, etc.)
All communications use standard TCP/UDP sockets on configurable ports. The protocol consists of binary sample frames with no arbitrary command execution beyond documented acquisition control.
Port Configuration
Control Port
Direction: Outbound from AFT3CH
Target: AcqKnowledge control port (configured in AcqKnowledge → Preferences → Networking)
Protocol: TCP
Purpose: Query acquisition, specify channels, start/stop via NDT commands
Data Ports
Direction: Inbound to AFT3CH (optional, only if on different hosts)
Source: AcqKnowledge host
Protocol: TCP or UDP (as configured)
Purpose: NDT binary data protocol for physiological streams
Firewall Summary: Only explicitly configured NDT ports between AFT3CH and AcqKnowledge are required. No exposure to wider network beyond these connections.
Security Profile
- NDT is unencrypted; intended for trusted LAN/VLAN or VPN environments
- Payload consists of physiological waveforms and metrics only—no OS-level data, credentials, or file access
- No arbitrary command execution capabilities
MQTT Telemetry (Optional)
AFT3CH can optionally send telemetry using MQTT as a client only, never as a broker. All connections are client-initiated and encrypted.
Dual-Layer Encryption
Transport Layer (TLS)
MQTT carried over encrypted TLS channel providing confidentiality and integrity on the wire. Tunneled through port 443 in restricted networks.
Payload Layer (AES-GCM)
End-to-end encryption using AES-256-GCM authenticated encryption. Only authorized endpoints with correct key material can decrypt message contents. Tampering detected via GCM tag.
Required Outbound: AFT3CH_PC → MQTT_ENDPOINT:443/TCP
No Inbound Required: AFT3CH does not accept MQTT connections
Firewall Configuration Reference
Required Rules
# NDT Control (Outbound)
From: AFT3CH_PC_IP
To: AcqKnowledge_PC_IP
Port: [NDT_CONTROL_PORT]/TCP
Purpose: Acquisition control and configuration
# NDT Data (Inbound, if different hosts)
From: AcqKnowledge_PC_IP
To: AFT3CH_PC_IP
Ports: [NDT_DATA_PORTS]/TCP or UDP
Purpose: Physiological data streams
# MQTT Telemetry (Outbound, optional)
From: AFT3CH_PC_IP
To: MQTT_ENDPOINT_IP
Port: 443/TCP
Purpose: Encrypted telemetry (TLS + AES-GCM)
# Update Check (Outbound, optional)
From: AFT3CH_PC_IP
To: updates.orbit-biomed.com
Port: 443/TCP (HTTPS)
Purpose: Version metadata retrieval