Why it matters
In 2026, researchers at ETH Zurich showed that a malicious server could swap public keys at several password managers and read what was shared. This is the defense.
Key transparency
A server that lies about a key gets caught.
To share with someone, your device needs their key, and it gets it from our server. Key transparency makes sure the server can't hand you a key of its own without being seen.
How it works
Key transparency, step by step.
Every key goes in a public log
The server keeps an append-only log of each account's key. It can add to the log, never rewrite it.
Your device checks before it shares
When you find someone to share with, Vallkey checks the key it's given against the log, and shares nothing if the log doesn't back it up.
Your devices watch your own entry
About once an hour, they check that the log has only ever held your key, and compare what they saw with each other.
The details
What careful people ask.
Fingerprints still work
Compare a fingerprint in person or on a call, eight groups of five digits, and you're protected from the very first share.
Open to auditors
The log publishes its signed heads, and proofs that it only grew, for independent auditors to check.
What to know
A brand-new device trusts the first log it sees. From then on, every change to anyone's keys is checked against it.
Availability
Where you get it.
- Plans
- Free, Premium, Families, Business
- Platforms
- Every app
Questions
What happens if Vallkey warns me?
Nothing is shared with the key in question. Compare fingerprints with the people you share with, in person or on a call.
Do I have to do anything?
No. The checks run by themselves while you use Vallkey.
Related
Your passwords. Your keys. Your price.
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