Your vault is locked before it ever leaves your device.

Three steps, all on your device

• You unlock with your master password: Your device turns it into an encryption key using 1,000,000 rounds of PBKDF2 and a salt unique to you. That slows down anyone trying to guess it.
• Your device encrypts everything: Each password, note and file is encrypted with strong 256-bit keys before it's saved or synced. Every encrypted value is sealed, so any change to it is detected. Items saved in an older format are re-encrypted this way the next time you unlock.
• SyFly stores only the locked copy: Our servers keep your encrypted vault so it syncs across your devices. Without your master password, what they hold is unreadable.

SyFly never sees

• Your master password
• The keys that open your vault
• Your saved passwords, notes and files
• What you share, in a readable form
• Your recovery key

SyFly stores

• Your encrypted vault
• Your email and profile, to run your account
• Your public key, so others can share with you
• A one-way hash of your account password, to sign you in
• Your private key, encrypted on your device, so your other devices can open your vault
• Security events, such as sign-in attempts

More than one lock on your account

• Account and vault are separate: Your account password signs you in. Your master password opens your vault and never leaves your device.
• A second step at sign-in: Add a code by email or text message, an authenticator app, or a hardware security key. Keep a set of one-time backup codes in case you lose your phone or key.
• Face Key and device biometrics: Face Key recognizes your face on your own device and never uploads your photo. Signing in with it also takes a code sent to your email and your PIN. A new device has to be approved from one you already use, with a code we email you and the number it shows. Removing Face Key or changing your PIN takes your current PIN or your two-factor step.
• Guessing gets stopped: After several wrong attempts, sign-in and unlock are paused for 15 minutes, and repeated requests are rate-limited. A device that goes unused for 30 days is signed out. The web app locks your vault after 15 minutes without activity, and the browser extension after 30 minutes or when your screen locks.
• Tampering is detected: Every encrypted value carries an authentication tag. Data that was altered is rejected, never shown.
• A lock for each container: Lock each container with your master password, its own passphrase or a security key such as a YubiKey, and choose how the people you share it with open it.

Choose how each container is locked

• Master password: Opens with the same master password as your vault. Simple, and just as strong as your master password.
• Passphrase: A separate passphrase for this container only, so even an unlocked vault needs it to open this container. Use at least four unrelated words.
• Security key: The container opens only with your physical key, such as a YubiKey. The key computes a secret that never leaves it (FIDO2). Register a spare key too: one container can open with any of your registered keys. Keep them somewhere safe.

Sharing a container locked with your master password

• When you share it, your device locks the container key with their public key (RSA-4096) straight away
• Someone who doesn't have a SyFly account yet gets their copy once they create one and you next open SyFly
• The first time they open it, their device re-locks their copy with their own account key. They can leave the container at any time

Sharing a container locked with a passphrase or security key

• You choose how your recipients open it: a passphrase you tell them, a security key (YubiKey) you give them, or the answer to a question
• With a security key you give away, you touch it once while sharing and it's added to their account, so they open the container with one tap
• Each recipient's copy is locked with that secret on your device and bound to them, so no one else can open it; SyFly never receives the secret
• Give the passphrase or answer in person or through another channel, never in the same message as the invitation

When someone shares a container with you

• Shared from a master-password container: it opens with your own keys, automatically
• Shared with a passphrase or an answer: you type it once on each device; your copy is yours alone
• Shared with a question and answer: SyFly shows you the question the owner picked
• Shared with a security key: tap the key the owner gave you; you can also add a copy that opens with your own registered security key
• If your copy can't be opened with your current keys, for example because it was locked under a master password you no longer use, SyFly asks the owner for a new one; it opens once the owner next opens SyFly

About the question and answer

• Only the answer locks the container. The question you pick is shown to your recipients, encrypted so only they can read it
• Answers aren't case-sensitive, and spaces at the start or end don't count. Longer answers need recipients who already have a SyFly account
• It's the most convenient choice and the least secure: real answers, such as a birthplace, are often easy to find or guess
• Prefer a passphrase for anything sensitive

Security keys, on every app

• Web and browser extensions: through your browser's security-key prompt
• Mac and Linux desktop apps: plug the key in over USB (the Linux build is still being prepared)
• Windows desktop app: one Windows prompt covers all your keys. Touching the key needs Windows 11 22H2 or later; on Windows 10 it doesn't work, in the app or in browsers
• Android: tap over NFC or plug in over USB. iPhone: tap over NFC

Good to know

• Once a container is protected with a security key, only a touch of one of your registered keys opens it: the typed YubiKey code no longer does
• If your key has a PIN, SyFly always asks for it
• Removing a key from your account removes it from every container it protected, in one step. SyFly won't remove the last key that opens a container: register another one first
• Older keys that only support U2F (such as early Google Titan or Feitian keys) can't hold a secret, and SyFly tells you so

Share safely with people and teams

Everyone on SyFly has a public key, which anyone can use to lock something for them, and a private key, which only they have and which is the only thing that can unlock it. Sharing uses that pair, so SyFly carries what you share without being able to read it.

• You choose who to share with: A person, a group or your whole team. Share a single password or note, a container, or a repository.
• Your device locks a copy for them: It encrypts the item's key with each recipient's public key (RSA-4096) before anything is sent.
• Only they can open it: Their device unlocks the copy with their private key, then keeps it locked with their own account key (AES-256-GCM). You can remove access at any time.
• Groups: A group has its own key, and each member receives a copy locked with their own public key. Share once with the group and every member can open it. New members get access to what was already shared with the group.
• New keys, same access: If someone you share with gets a new key pair, your device locks a fresh copy for their new public key the next time you unlock. Nothing is ever sent unlocked.
• Organizations: Manage members, groups and shared spaces for your company, with single sign-on for organizations that use it.
• Backup person: Choose someone who receives a container if you stop using SyFly, so important information isn't lost. Their copy is locked with a passphrase you tell them or a security key you give them, and SyFly releases it only after your inactivity period ends or you approve their request. Your message to them is encrypted too, readable only by you and them, and it stays readable when either of you changes keys.

The details

• Key from your master password: PBKDF2-HMAC-SHA256, 1,000,000 iterations, a random 16-byte salt per user, 256-bit output
• Vault keys: A random 256-bit account key, with a separate key per purpose derived with HKDF-SHA256
• Encryption: AES-256-GCM with a random IV for every value and a 128-bit authentication tag
• Sharing: RSA-OAEP with 4096-bit keys and SHA-256 to the recipient's public key, at the moment you share; the recipient's device then re-locks its copy under their account key (AES-256-GCM). One group key per group, locked for each member
• Shared with a passphrase, answer or security key: Each recipient's copy is locked with that secret and bound to them: PBKDF2-HMAC-SHA256 (passphrase or answer) or FIDO2 hmac-secret (security key), then AES-256-GCM. A security key you hand over has its registration added to the recipient's account. A question-and-answer share's question is encrypted to each recipient with RSA-OAEP
• Container passphrases and security answers: PBKDF2-HMAC-SHA256 with a random salt per copy, 256-bit output, then AES-256-GCM
• Security key (YubiKey): FIDO2 hmac-secret (WebAuthn PRF): the key computes a 32-byte secret from a random salt stored per key; SyFly derives an AES-256-GCM key from it with HKDF-SHA256. The secret is never sent or stored. Up to 10 keys per account
• Backup person: Their copy of the container key is locked with the passphrase or security key you chose (as above), released only when the backup is triggered
• Backup-person message: AES-256-GCM with a random key per message; that key is locked with RSA-OAEP for you and for your backup person
• Where it runs: On your device: web, desktop, mobile and browser extensions all use the same verified format
• Account password: Stored only as a bcrypt hash
• Your keys on the server: Your keys are stored only in encrypted form; only your public key is readable by others

Only you hold the key

Everything in your vault is locked on your device and opened on your device. That's the promise behind SyFly, on every platform you use it.

Questions

Can SyFly reset my master password?

No. Because we never know your master password, we can't reset it or open your vault for you. Save your recovery key when SyFly offers it: it's the way back in if you forget your master password.

What happens if SyFly's servers are breached?

An attacker would find encrypted data they can't read without your master password. Choose a long master password you don't use anywhere else, so it can't be guessed.

Can SyFly employees see my passwords?

No. Your vault is encrypted on your device before it reaches us, and we don't have the keys to open it.

Is my face stored when I use Face Key?

Face Key works on your device. It turns your face into part of a key there and uploads only encrypted data. Your photo isn't uploaded. The other part of the key comes from SyFly's servers, and only after you enter the code we email you and your PIN, so even a copy of our database can't open your Face Key. After 5 failed attempts it locks for 15 minutes. The face model is SFace, published by OpenCV under the Apache 2.0 licence. In our tests no other person's face came within its limit; the closest were identical twins, who would still need your email code and PIN.

How long does SyFly keep my Face Key data?

Face Key asks for your consent before you set it up. Its encrypted data is deleted when you remove Face Key or delete your account, and at the latest 3 years after you last used SyFly. SyFly never sells or shares it.

Why did Face Key add a new look by itself?

When you sign in with Face Key and your face is recognized but only just, for example in new light or a new place, Face Key saves that sign-in's face as an extra look so it recognizes you more easily next time. It only does this right after a full Face Key sign-in, and we email you each time. You can remove any look in Settings → FaceKey; looks saved this way are marked "learned".

Do Face Key or AutoFill keep my master password?

No. Face Key opens your vault with your account key, which it keeps encrypted with your face and the server's part of the key; it never stores your master password or anything made from it. AutoFill on your phone or Mac uses the key your unlocked SyFly app opened, and never stores your master password either.

What happens when I change my master password?

Your device re-locks your account key, your recovery copy and every key still tied to your master password, and sends them together. SyFly saves all of it in one step or none of it, so a failed change leaves your vault exactly as it was. Copies saved in an older format are converted first, so nothing is left behind under the old password. If you sign in with Face Key or on a new device while older copies remain, SyFly asks for your master password once to finish upgrading your vault.

Why are there two passwords?

Your account password proves who you are when you sign in. Your master password encrypts your vault. Keeping them separate means that even a signed-in session can't open your vault without the master password.

What if I lose the YubiKey or forget a container passphrase?

That container can't be opened without it, by you or by SyFly. Register a second security key on the container, keep a written copy of the passphrase somewhere safe, or share the container with a backup person.

Which security keys work?

Keys that support FIDO2 with the hmac-secret extension, such as current YubiKeys. Older keys that only support U2F can't lock a container.

Can the people I share with see my other items?

No. SyFly sends each person only what you shared with them. Each container and each item has its own key. Sharing a single item from a container gives the person that item's key only, never the container's. If a container's key was handed over that way in the past, your device gives the container a new key, and may ask you to re-enter the secrets you chose for your backup person or recipients.

What's a strong master password?

Length matters most. A passphrase of four or more unrelated words is easy to remember and hard to guess. Don't reuse it for any other account.

How do I report a security issue?

Use the form on the Report a vulnerability page (syfly.io/security/disclosure) and include the steps to reproduce it. The same page has our full policy: reply and fix times, safe harbor for good-faith research, and what is in scope.