Time-Check

How It Works

Time-Check enables secure, anonymous calendar availability sharing across organizations without revealing personal information or requiring calendar access.

The Process

1. Anonymous Request

Alex (Company A) wants to check Joe’s (Company B) availability
Alex submits a request using Joe’s email address
Request includes anonymous device ID and time range
No personal information about Alex is revealed

2. Client Check-In

Sarah (Company B employee with Time-Check app) checks in periodically
App receives encrypted availability requests for company colleagues
Requests are matched to colleagues based on verified email addresses
No personal details about requestors are visible

3. Calendar Processing

Sarah’s device accesses Joe’s calendar (with permission)
App extracts only busy/free time slots - never meeting details
Calendar data is processed locally and never transmitted
Availability is converted to encrypted bitmap format

4. Encrypted Response

App generates encrypted availability response
Uses unique encryption keys for each request
Response contains only busy/free bitmap - no calendar details
Encrypted data is stored temporarily on server

5. Secure Retrieval

Alex retrieves the encrypted response using their private key
Only Alex can decrypt the availability information
Server cannot access the decrypted calendar data
Response expires automatically after retrieval

Security Features

Zero-Knowledge Architecture

Server never sees decrypted calendar information
All sensitive data is encrypted end-to-end
No persistent user identities or tracking
Anonymous device IDs rotate automatically

Email-Based Verification

Users verify their work email address
Prevents unauthorized access to calendar data
No calendar email extraction required
Secure, reliable identity verification

Minimal Data Transmission

Only busy/free time slots are shared
No meeting titles, participants, or locations
Efficient bitmap compression (70-90% size reduction)
Data expires within 30 days

Privacy Protection

No Personal Information

Calendar event details never leave your device
Anonymous request system prevents tracking
No user profiles or persistent accounts
Cross-company requests remain anonymous

Local Processing

All calendar analysis happens on your device
No cloud processing of sensitive information
EventKit framework provides secure calendar access
Background processing with minimal battery impact

Automatic Cleanup

All data expires automatically
No long-term storage of availability information
Temporary encryption keys are discarded
Rolling device IDs prevent long-term tracking

Next Steps: Download the iOS app or learn about our security architecture.