You appear to have Javascript disabled. Javascript is required for this application. Please enable it and reload this page.
Sorry, SC4 does not currently work with Microsoft Internet Explorer. Please use Firefox instead. (SC4 also works with Chrome and Safari, but Firefox is a better choice from a security point of view.)
Initializing... this should take less than one second. If you can actually read this message, something has gone wrong.

SC4 Error

You appear to have private browsing mode enabled. SC4 stores important information (your encryption keys) in your browser's localStorage, which is disabled when private browsing mode is turned on, so SC4 won't work. To use SC4 please disable private browsing mode and reload this page. If you are paranoid (and there's nothing wrong with being paranoid where security is concerned) you can disconnect from the network after you have re-loaded this page. SC4 is a standalone application and does not require a network connection.

Welcome to SC4!

Secure Communications for Mere Mortals

SC4 is a web application that lets you send locally encrypted files and generate secure digital sigatures.

For more information click here.

To get started, please enter your email address:


Thank you for signing up. You wil receive a confirmation email shortly. Please click on the link in that email to confirm that this email address really does belong to you. Or you can start using SC4 right away by clicking here. But until you confirm you email other people will not be able to connect with you.

Welcome to SC4!

You are running this code from a local copy rather than from a server. In order to be secure when running this way you need to generate a customized version of SC4 that has your private keys embedded within the code instead of being stored in your browser.

To generate a copy of SC4 that you can run from a local file . Save the resulting file and then open it in your browser. IMPORTANT: this file will have your keys embedded within it, so don't share it with anyone!

NOTE: It is strongly recommended that you run this in Firefox or Chrome and not Safari. This is because Safari discards the suggested file name of locally generated downloads, but the file name needs to be randomized in order to better secure the embedded keys.
Generating a local copy of SC4 with embedded keys...

Uploading encrypted data...

Drop file to process it


Secure Communications For Mere Mortals

Send to: or Help

Drag-and-drop a file, or enter text: Demos and advanced features

Encrypt Sign