1: Get a Key Id

  • A "Key Id" is a unique URL which points to a mailbox that accepts encrypted messages.
  • Only those who know the passphrase will be able to retrieve the message sent to the Key Id.
  • We recommend you leave the passphrase field blank to generate a strong, random passphrase.

2: Send Messages & Files to a Key Id


3: View Messages sent to a Key Id

About CryptAByte is a free online drop box that enables secure (encrypted) message and file sharing over the web using a public-key infrastructure.

Messages and files are encrypted using a public key and can only be decrypted using the passphrase entered when your key is created. Your data is never stored in plaintext, and is impossible to decrypt without your passphrase.

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Would you like to run a copy of CryptAByte on your website or private Intranet?

Why Use CryptAByte?

Crypt-A-Byte uses public-key encryption just like HTTPS/SSL and OpenPGP/PGP. We encourage you to use these tools whenever possible.

However, PGP requires that you and your recipient install and configure encryption software and create and exchange key pairs. When this is not practical, we make it very simple (and free) to share data using the same algorithms over the web.

We use RSA for key pairs, encrypt messages and files using AES 256, and SHA256 for hashing.


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Keys (and messages) may be deleted 30 days after the lock date. The default lock date (customize in the advanced option of the create key dialog) is 30 days from the key creation date.

This service is completely anonymous and keeps no user-specific records. It is impossible to decrypt your data without the passphrase you provide when a key is created. Furthermore, we do not record IP addresses or any other user-specific information. We do have access to your key at the moment you enter it, and may be forced to record your passphrase under a court order. (Read more)
To eliminate this risk, we encourage you to use our API or the open-source offline app for Windows/Mac (coming soon) to access your data.

Usage Scenarios

Basic Scenarios:

  • Secure messaging
  • Secure file sharing
  • Secure chat client
  • Offline message support
  • Secure email client

Advanced Scenarios:
When using the "release date" option (available via UI and API) messages can be delivered, but cannot be retrieved before a certain time.

  • Placing bets: each participant enters their guess at the public URL, but the answer cannot be seen until the release date.
  • More to come...

Terms & Conditions

Remember that as long as your keep your passphrase secret, it is impossible for anyone else to know what you use this service for. However if you publicly disclose your passphrase and anyone complains, we'll just delete your key (and thus any messages/files sent to it).

Intellectual Property Complaints: If you object to any information being stored on this site, please send us the Key Id and passphrase via the contact page.