Security

Core51 makes security part of everyday work. It verifies who you are talking to, warns the team if a contact’s encryption key changes, and signs messages so tampering can be detected. Chat exports also include verification data, so important conversations can be checked later instead of relying on screenshots or trust alone.

End to end encryption

messages are encrypted on device and decrypted only by participants. The server stores ciphertext and routing metadata (delivery state, timestamps, IDs). This keeps confidentiality resilient even if the infrastructure is compromised.

Key continuity (TOFU)

on first contact, keys are pinned. If a peer key changes, the client shows a warning and requires explicit re trust. This protects against silent interception, including scenarios where an attacker attempts to rotate keys without user awareness.

Integrity signals

messages are signed by the sender (Ed25519). Exports include integrity related metadata (commitments or chain state) that supports later verification. This is important for audits and disputes: you want to demonstrate what controls existed, how changes were handled, and what proof is available.

Operational security

key rotations can be reviewed. This supports incident response and compliance workflows.

Arbitration and disputes

Sometimes you need a chat to serve as proof of a deal. Core51 supports two simple export models - choose the one that matches your situation.

Two export models

1) Decrypted text (for pre-trial actions)

This is the practical option when you need to act fast: a claim letter, negotiations, mediation, a notary, or other pre-trial steps.

What you share: readable message text (and timestamps / participants).
Why it is useful: people can read it immediately.
Important note: the recipient must trust the text was not edited.

2) Encrypted proof package (for court / forensic review)

You export an encrypted chat bundle. It stays encrypted until the account owner decides to reveal the private key. After the private key is provided, the bundle can be decrypted and checked.

What you share first: an encrypted export file.
When plaintext is revealed: only after the private key is provided.
Why it is useful: an expert can verify the decrypted transcript matches the exported package.

Which one should I use?

Use model 1 when

You need speed and readability: pre-trial letters, settlement talks, negotiation, or mediation.

Use model 2 when

You need maximum credibility and technical verification: court disputes, expert review, or situations where the other party may claim fabrication.

Audit program

Audit-Ready

External audits on a regular schedule

After signing an NDA, your IT/security specialists can be granted access to conduct an audit according to an agreed schedule.

Next open audit day: 15 July.