Tresorit uses two types of profiles to keep your files secure and accessible across devices:
Roaming profile – your secure keys, encrypted and synced across devices.
Local profile – device-specific info, stored only locally.
Both are encrypted, but they serve different purposes.
Roaming profile
Your roaming profile holds the encryption keys needed to access and decrypt your files. It is protected with a key derived from your password, which never leaves your device, and is stored in the cloud so you can sign in securely from any device.
Sign-up
When you create a Tresorit account, encryption keys are generated to protect your data. A random 256-bit salt is created and combined with your password using scrypt, a key-derivation function designed to resist brute-force attacks. The result is your master key, which encrypts your roaming profile with AES-256-GCM. This ensures that your profile remains confidential and any tampering can be detected.
From the same process, a cryptographically independent authentication key is also derived. This key is sent securely to Tresorit's servers and is used only to verify your identity the first time you log in on a new device.
ℹ️ Key derivation uses scrypt (RFC 7914) with parameters N=32,768, r=8, p=1, followed by an additional HMAC step with SHA-256 (FIPS-180-4). Encryption is performed with AES-256-GCM for both confidentiality and integrity protection.
First-time login on a new device
When you sign in on a new device (or after reinstalling your system), Tresorit downloads your encrypted roaming profile from the cloud. Since your device doesn't yet have its own certificates, a challenge–response protocol is used.
The server sends a random challenge, and your client re-derives the authentication key from your password and proves your identity by returning a valid response.
Once authentication succeeds, your roaming profile is downloaded and decrypted locally using your master key. At this point, Tresorit generates new device-specific keys: one is used for SSL/TLS communication, and another updates your roaming profile. These keys never leave your computer and are stored securely in your local profile.
ℹ️ Authentication is based on PBKDF2 + HMAC (SHA-1) with salts and nonces, following NIST 800-132.
Regular login
On a device where your profiles already exist, login doesn't require server communication. The client decrypts your local profile, without needing to contact the server. If you use your password, a local master key is derived with PBKDF2 and SHA-256 (100,000 iterations) – this local key is different from the one that protects your roaming profile.
Auto-login
If you enable auto-login, Tresorit stores an additional key in your operating system's secure storage. This key can unlock your profile without requiring your password each time.
Local profile
Your local profile contains information needed to map Tresorit folders to your device. It exists only on your device and is never uploaded to the cloud. Like your roaming profile, it is encrypted and integrity-protected with AES-256-GCM.