Understanding Encryption
A simple, plain-English guide to how SecureShare protects your files using public keys, private keys, and AES.
AES Encryption (The Safe)
Imagine you have an unbreakable safe. To put a file in the safe, you need a highly complex, random password. In cryptography, this is called Symmetric Encryption (AES).
When you upload a file to SecureShare, your browser generates a brand new, random AES password (called a key) just for that file. It puts the file in the safe, locks it with the AES key, and sends the locked safe to our servers. Because we don't have the key, we can't open the safe.
Public Key (The Padlock)
Now, how do you share that AES key with someone else securely? You can't just email it, because someone might intercept the email. This is where Asymmetric Encryption comes in.
Every SecureShare user has a Public Key. Think of this as an open padlock. You can give copies of this padlock to anyone in the world. If someone wants to send you the AES key for a file, they put the AES key in a box and snap your open padlock shut on it.
Private Key (The Only Key)
Once your padlock is snapped shut, no one can open it—not even the person who closed it. The only thing in the universe that can open that padlock is the single, unique Private Key.
Your Private Key never leaves your device. When someone shares a file with you, they send the locked box (containing the AES key) to your browser. Your browser uses your Private Key to open the padlock, takes out the AES key, and uses it to open the safe containing the file.
Because your Private Key never leaves your device, if you lose your device and your 12-word recovery phrase, your Private Key is gone forever. Without it, none of the padlocks can be opened, and your files cannot be recovered.
Want the technical details?
Read the Security Architecture