What is End-to-End Encryption?

End-to-end encryption (E2EE) is a method of secure communication where only the communicating parties can read the messages or data. In the context of file transfer, it means only the sender and intended recipient can access the file contents.

How E2EE Works

The Basic Process

Key Generation: Each participant generates a public-private key pair
Key Exchange: Public keys are exchanged (private keys never leave the device)
Encryption: Data is encrypted using the recipient's public key
Transmission: Encrypted data travels through any medium
Decryption: Only the recipient's private key can decrypt the data

In WebRTC

WebRTC implements E2EE through DTLS (Datagram Transport Layer Security):

Sender Device → [Encrypted Data] → Network → [Encrypted Data] → Receiver Device
                     ↑                              ↑
              No one can read this, not even the network operators

Types of Encryption

Symmetric Encryption

Same key for encryption and decryption

Fast and efficient

Challenge: How to share the key securely?

Asymmetric Encryption

Different keys for encryption (public) and decryption (private)

Solves the key distribution problem

Slower than symmetric encryption

Hybrid Approach (Used in WebRTC)

Use asymmetric encryption to exchange a symmetric key

Use the symmetric key for actual data encryption

Best of both worlds: secure key exchange + fast encryption

Why E2EE Matters

Without E2EE

Service providers can read your data

Government agencies can request access

Hackers who breach servers get everything

With E2EE

Only you and your recipient can read data

Service providers see only encrypted gibberish

Server breaches yield nothing useful

Common Misconceptions

"HTTPS is enough"

HTTPS protects data in transit but not on servers. Once data reaches a server, it may be decrypted and stored in plain text.

"Cloud services encrypt my data"

Many cloud services encrypt data at rest, but they hold the encryption keys. This means they (or anyone who compromises them) can decrypt your files.

"Encryption is too complicated"

Modern solutions like ZeroSend handle all encryption automatically. Users don't need to understand cryptography—they just need to share a code.

The Math Behind Security

Modern encryption uses keys so large that brute-force attacks are practically impossible:

256-bit AES: Would take billions of years to crack with current technology
2048-bit RSA: Provides equivalent security for key exchange

Conclusion

End-to-end encryption is not just a feature—it's a fundamental requirement for true privacy. When choosing a file transfer solution, ensure it implements E2EE where only you and your recipient hold the keys.