Send Messages to the Future

Freeze your words. We'll deliver them when it matters.

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Secure by Design

Your secrets are safe with us

Military Grade
Encryption
Zero Trust
Required
Set & Forget
Automation
Client-side Encryption
Your messages are encrypted in your browser before they ever touch our servers. We never see the plaintext.
Timelock Encryption
Messages are locked with timelock encryption, guaranteeing they can only be decrypted after a time set by you.
Open Source & Verifiable
Cryopost is open source. You can inspect the code, verify our claims, and even host it yourself.Read our detailed security documentation ortry our open-source decryptor.

How It Works

A simple, secure process

  1. 1

    Write Your Message

    Compose the secret message you want to deliver in the future. Add recipients and set the delivery conditions.

  2. 2

    Encrypt & Lock

    Your message is encrypted client-side with AES-GCM and then timelocked using drand. Only future drand beacons can unlock it.

  3. 3

    Check-in Regularly

    Periodically check-in to confirm you're okay and keep your message locked. You choose the frequency that works for you.

  4. 4

    Automatic Delivery

    If you miss your check-in deadline, your message is automatically decrypted and delivered to your recipients.

For Security Researchers & Cryptographers

Want to dive deeper into our cryptographic implementation? Our detailed technical documentation covers threat models, attack vectors, and implementation details.

View Security Architecture→

Pricing

Choose Your Plan

Start free, upgrade when you need more power and flexibility