Tella is a documentation app for Android. In challenging environments--with limited or no internet connectivity or in the face of repression--Tella makes it easier and safer to document events, whether that’s violence, human rights violations, corruption, or electoral fraud.
Tella has three main objectives:
Tella's code is publicly accessible for anyone to review and audit here on our GitHub repositories. Rather than blindly trust us, audit the code yourself or ask someone you trust to do it. If you don't know someone who can audit our code, check out the report of the security audit conducted by Cure53, a security firm specialized in finding vulnerabilities. The report is available here on Cure53's website (note that at the audit was done on "Whistler", which Tella was initially based on).
Tella integrates various security measures in place to achieve an acceptable level of security:
All data is encrypted at rest, on the user's device. This means that unless the app is unlocked (by entering the user's pattern), the data it contains cannot be accessed at all. Even if someone seizes the phone and extracts all the data using a computer, the data will remain unreadable. The encryption library we use is SQLCipher.
By default, Tella only collects anonymized data for bug reports. Sharing bug reports can be disabled in the app in Settings > General > Share bug reports.
If you connect to a server and fill forms for an organization you work with, Tella shares the data that is attached to the forms. That data only goes to the organization's servers, never to ours.
Tella includes a feature called “Verification Mode”. When Verification Mode is activated, Tella collects a whole bunch of information every time you take a photo, a video, or record audio. This information includes data about your device, your network, and your location. This information can then be used by researchers, lawyers, or journalists to verify the origin of the file.
For Verification Mode to be as useful as possible, Tella asks permission to access GPS location (specifically
ACCESS_FINE_LOCATION). You are free to deny this access, but the verification information will be less valuable to those attempting to verify the file.
Verification Mode is disabled by default, and Tella does not collect your location unless you activate Verification Mode.
You can read more about Verification Mode on this page.
When we talk about documentation, we mean any attempt to document things and events: this could mean taking photos and videos, recording audio and making interviews, filling forms and surveys, etc.
Tella includes an "Offline Mode" for users who are collecting data in remote areas with limited or no internet connection. When Offline Mode is activated, all data is saved on the app and and users can submit it easily when they reach an internet connection.
All you have to do to collect data offline is: