Nothing on the phone.Nothing readable on the server.Nothing recoverable later.

Secure messaging and voice for organizations whose conversations must never resurface. Keys that destroy themselves on your schedule, a relay that can neither open nor trace what it carries, and — only in Cortext — an encryption key you can choose with your own people.

Request information and pricing Why Cortext

Hybrid post-quantum · ML-KEM-1024

09:41

Field teamExpiring · 6 hours

Encryption expires in 0m 05sEncryption expired — key destroyed

Survey complete. Coordinates follow.

Received. Nothing of this will exist by tonight.

Encryption expires in 5h 58m · at 03:00

Acknowledged. Same window tomorrow.

Message

The countdown is real.At the stated instant the key is destroyed on both devices — even mid-conversation.

Expiry to the minute each message’s key dies on the schedule you set

A key you choose a phrase agreed with your team, never on any machine

Post-quantum throughout every key agreement, every call, on the CNSA 2.0 suite

Runs where you decide our servers, a dedicated instance, or your own

Your key

Choose the encryption key yourself: a phrase agreed between you and your team, never stored, never shown, never sent. No algorithm made it, so no algorithm can be attacked to recover it.

Zero persistence

No message store on the device. Plaintext exists only while it is on screen and is overwritten the moment it leaves. Keys destroy themselves on schedule. Theft, backup and forensic imaging recover nothing.

Quantum-resistant

Every key agreement is hybrid post-quantum on the NSA’s CNSA 2.0 suite. What is recorded today remains sealed against the computers of tomorrow.

Coercion-resistant

A second password opens a convincing decoy — or quietly erases the real account. Nothing on the phone or the server reveals that the option exists.

The encryption key can be yours to choose.

In every other messenger, a machine generates the key. In Cortext you can create it yourself: a phrase agreed between you and your team, in person, by any channel you trust. It is never stored, never displayed, never transmitted — only keys derived from it ever exist.

A machine-made key is the output of a process, and a process can be attacked: a weakened random-number generator, a backdoored library, malware present at the moment of creation. A phrase born between people has no generation process to attack. No server, no wiretap, no compromise can produce or counterfeit it.

Automatic

Keys agreed by the devices through a signed, hybrid post-quantum handshake. Strongest convenience.

Passphrase

You and the other person agree a phrase for the conversation. It is combined with the keys generated on both devices as real key material: an attacker must break both, and the phrase never existed on any server.

Sealed

The same conversation phrase, with one more rule: it is asked for at every session and joins every message key. A stolen, unlocked phone reads nothing. The key lives in your heads.

The tier is chosen per conversation. Automatic for everyday traffic, passphrase for your inner circle, sealed for what must survive the theft of the phone itself. Your login password is a different thing entirely: it opens your account, never leaves your phone, and is never part of any conversation key.

Every claim on this page is a screen in the app.

Cortext is a finished product on iOS and Android. Three of its screens:

09:41

Conversations+

FField team Expiring · 6 hours2
PProject Atlas Maximum secrecy
DDana Sealed · phrase required
OOps desk Expiring · 24 hours
AAuditors Expiring · 7 days5

Choose how long history lives — per conversation. Expiring for 1 hour to 7 days, maximum secrecy that is never re-read, or sealed behind a phrase only two people know.

09:41

FField team Connected · 02:14 · encrypted

Say these words to each other

harbor · silent · copper
meadow · pilot · orbit

Different words on the two screens mean someone is in the middle.

Codes match — unmute

micVerify firstspeakerend

Calls you verify out loud. Six words bound to the real media path; with Verify Calls Before Speaking on, the microphone stays muted until both sides confirm.

09:41

Security

Lock When Leaving the App Wipe keys and messages from memory whenever the app goes to the background
Verify Calls Before Speaking Microphone stays muted until the codes match
Always Ask for Password No automatic biometric unlock at launch
Stealth mode Constant-rate cover traffic hides when you communicate
Duress protection Second password: decoy, or destroy

Every trade-off is the user’s choice. The protections that create metadata or cost convenience are switches, never forced defaults.

Whatever they get hold of, they read nothing.

Ordinary secure messengers defend against someone listening on the network. Cortext is engineered for every position a determined adversary can actually reach — and it is the only messenger that answers all of them at once. Assuming each compromise is total, this is what they obtain.

The adversary holds	What they can read
The server — database, memory and logs	No message or call content. No passwords or keys, which never reach it. No social graph of current conversations — messages travel over anonymous delivery codes. No indication that a duress credential exists.
The network — full packet capture	Ciphertext inside TLS 1.3 with certificate pinning. With cover traffic enabled, timing and volume are uniform as well.
The call relay	Only encrypted media frames: every audio frame is sealed above the transport layer, under anonymous relay credentials.
A stolen device — locked, or with the lock engaged	Nothing. There is no message database, no cached plaintext and no key in memory. What remains is hardware-wrapped and opens only to the owner’s biometric or password.
A stolen, unlocked device plus the server	The conversation currently on screen, for expiring conversations whose keys are still alive. Expired messages: nothing — the keys no longer exist. Sealed conversations: nothing without the phrase that lives only in the users’ heads.
Coercive power over the user	A duress password yields a plausible decoy account — or, if armed, the real account has already been irreversibly destroyed by the unlock itself, invisibly.
A recording of all traffic today and a quantum computer tomorrow	Nothing. Every key agreement is hybrid with ML-KEM-1024, including single-use pre-keys, so recorded traffic stays sealed while either the classical or the post-quantum assumption holds.

The relay is a courier, never a reader.

Every message is sealed on the sending device. The relay stores and forwards sealed envelopes addressed to anonymous delivery codes; it holds no key, no password and no membership list, and it cannot open what it carries.

What the relay holds

Sealed envelopes addressed to anonymous delivery codes — never to identities
A login verifier that cannot reveal the password
A key vault it cannot open

What the relay never has

Any password, or any key
Any message or call in the clear
Who communicates with whom
Whether a duress credential exists

This is a property of the design, not a policy: the data never reaches the server.

Capabilities.

Six more properties of the platform, none of them available in this form in any mainstream messenger.

Zero persistence on the device

There is no message database. Decrypted text exists only in working memory and is overwritten the moment a conversation is closed, switched, deleted or the application leaves the foreground. History, where the conversation allows it, is re-fetched from sealed envelopes on the relay and only while its key is still alive.

With Lock When Leaving the App engaged, the process holds no key and no plaintext the instant it leaves the screen; return requires biometric or password unlock, and no message in flight is lost.

Cryptographic expiry, to the minute

Conventional “disappearing messages” are a deletion policy: the client agrees to remove the text while keys and ciphertext may survive in backups, forensic images and on the other device.

Cortext keys each message to time. The retention window — 1 hour, 6 hours, 24 hours or 7 days — is fixed when a conversation is created and bound into the signed handshake, so neither party nor the server can extend it. Each message’s key is destroyed within the window plus at most one forty-eighth of it. Archived ciphertext then has no key anywhere, and the screen shows the countdown to that instant.

Nothing leaves the screen unnoticed

Screenshots and screen recordings come out black, on iOS and Android alike, and cannot be switched off. When someone tries, the other person receives an encrypted alert in the conversation. And when a message is copied, its author sees it marked “copied by” that person — so what was said stays between the people who said it.

Verified, end-to-end encrypted voice

Each call derives its key from fresh keys, post-quantum keys and the conversation’s own secret, authenticated by ML-DSA-87 identity signatures. Every audio frame is encrypted above the transport, so a compromised relay carries only ciphertext. A six-word code on both screens is bound to the actual media path; an interception changes the words. Optionally the microphone stays muted until the code is confirmed.

Metadata-blind relay

Conversations travel over anonymous delivery codes derived independently on each device; delivery and read receipts travel peer-to-peer inside the same sealed channel. Cover traffic emits fixed-size packets at a steady rate and the relay mixes deliveries, so an observer cannot tell when or how much a user communicates.

Duress protection

A second password, entered under coercion, opens a plausible decoy account — or, if armed, irreversibly destroys the real one through the same server operation as a routine credential change. Every login probes two identities with identical traffic; neither the server nor an observer can distinguish a duress unlock, or learn whether duress is configured.

Three ways to run it. One app.

The same Cortext app, from the App Store and Google Play, connects to Cortext’s own servers out of the box. An organization that wants its own server enrolls its people with a signed organization code — and the app connects there instead.

Cortext hosted

Install the app, create an account, start. Operated by Cortext on dedicated hardware, zero-knowledge from the first message. The fastest way to begin.

Dedicated instance

Your organization’s own isolated server — its own database, domain and certificates — operated by Cortext under a leasing agreement, in the country and jurisdiction you require. No shared tenancy, no access needed on your side.

Licensed on-premises

Signed server images installed on your own infrastructure under licence, with server and app updates supplied by Cortext for the term. Your hardware, your network, your rules.

Enrollment without addresses

Nobody types a server address or port. An organization receives a signed enrollment code, shown to each user as a QR code or a short code. The app verifies the code’s signature against a root key built into the app, then pins that server’s certificate — so no directory, network or attacker can point a user at a different server. Administrators issue single-use invites, so only the people they choose can register.

Licensing, seats and updates

Licences are per organization, for a term and a number of users. Renewals reach every phone automatically through the server; an expired licence is refused by the apps themselves. App updates arrive through the stores; server updates arrive as signed images. Accounts remain a username and a password only — no phone number, no e-mail address.

The relay stores ciphertext it cannot read, addressed to codes it cannot map to people. Deleting a conversation removes its ciphertext from the relay at once, and the reference deployment keeps no database backups: a backup would be a copy of sealed vaults whose keys the devices have already destroyed. Identity-bearing server logs are off by default, call signaling state is deleted at hang-up, and relay credentials carry no user identity.

Standards, assurance and documentation.

All cryptography is standardized, and the key schedule is aligned with NSA’s Commercial National Security Algorithm Suite 2.0. Post-quantum and classical keys are always combined, so a session remains sealed while either assumption holds.

AES-256: every message, vault, note and call frame
SHA-384: the entire key-derivation schedule
ML-KEM-1024: every key agreement — conversations, calls and one-time pre-keys
ML-DSA-87: every identity signature and key-exchange authentication

Implementation integrity

No invented cryptography: only published standards with known-answer tests (NIST FIPS 197, 203 and 204; SP 800-38D; FIPS 180-4; RFC 5869, 7748, 8446 and 9106), composed in new ways. The post-quantum primitives are a formally verified upstream implementation, pinned with an integrity manifest and validated against NIST’s official test vectors in the test suite. Wire formats are version-tagged so incompatible peers fail cleanly rather than negotiating downward.

Assurance program

The platform is under continuous, structured internal security review, and its security behaviour is pinned by nearly three hundred automated tests, including a two-device harness that exercises the real end-to-end flows. Independent third-party audit and machine-checked formal verification of the protocol are the next steps of the program. The full security whitepaper is available on request.

Where consumer messengers stop.

Capability	Cortext	Signal	WhatsApp	Telegram
Dedicated instance or your own infrastructure	Yes	No	No	No
Account without phone number or e-mail	Yes	No	No	No
No message database on the device	Yes	No	No	No
Screenshots, recordings and copies reported to the other party	Yes	No	No	Partly
Lock that leaves no key in memory	Yes	No	No	No
Expiry by key destruction, to the minute	Yes	No	No	No
Human-originated key material	Yes	No	No	No
Server blind to who communicates with whom	Yes	Partly	No	No
Cover traffic against traffic analysis	Yes	No	No	No
Duress credential: decoy or self-destruct	Yes	No	No	No
Post-quantum for conversations and calls	Yes	Conversations only	No	No
Per-call code bound to the media path	Yes	No	No	Partly

As publicly documented at the time of writing; capabilities of other products evolve. The difference is scope: consumer messengers are engineered against an interceptor. Cortext is engineered for the server operator, the archive, the stolen device, the coerced user and the quantum adversary, all inside the threat model at once.

Ready when you are.

Tell us about your organization, the number of users and where you want the server to live. We come back with a proposal, pricing, a deployment plan and the security whitepaper.

Request information and pricing

One e-mail is enough. Enquiries are answered directly, without a sales funnel. You receive:

A proposal and pricing for your number of users
A deployment plan: hosted, dedicated instance or on-premises
The full security whitepaper

info@cortextapp.com