How does end-to-end encryption work?

End-to-end encryption (E2EE) is a system of communication where only the communicating users can read the messages. The messages are encrypted by the sender but the third party does not have a means to decrypt them, and stores them encrypted. The recipients retrieve the encrypted data and decrypt it themselves.

Which cryptography technique is used by WhatsApp to provide end-to-end encryption to its users?

Signal Protocol
WhatsApp uses Signal Protocol developed by Open Whisper Systems.

What encryption method does signal use?

Signal messages are encrypted with the Signal Protocol (formerly known as the TextSecure Protocol). The protocol combines the Double Ratchet Algorithm, prekeys, and an Extended Triple Diffie–Hellman (X3DH) handshake. It uses Curve25519, AES-256, and HMAC-SHA256 as primitives.

How is Signal Protocol implemented?

Initialisation

1. Generate Identity Key & Registration ID for each User.
2. Store these to Signal Protocol Store (SSS) – InMemorySignalProtocolStore.js from Github.
3. Generate Pre-key & Signed Pre-key using the Identity Key & Registration ID from SPS.
4. Store these to SPS.

How does WhatsApp exchange keys?

WhatsApp uses these keys and the Curve25519 encryption and SHA256 hashing algorithms to create keys and encrypt messages. When you chat with someone it saves that key exchange so that it does not have to repeat that key exchange when you chat with them again.

How does WhatsApp generate keys?

Whatsapp has to first establish an encrypted session to obtain the security key. It uses this security key to encrypt your message. Since you are offline, hence this encrypted session may not be established and thus your message will not be encrypted.

Are signals end-to-end encrypted?

Signal is designed to never collect or store any sensitive information. Signal messages and calls cannot be accessed by us or other third parties because they are always end-to-end encrypted, private, and secure.

How do you make an end-to-end encryption chat?

End-to-End encryption for a chat application

1. Step 1: Generate public and private key in the Client and Server sides.
2. Step 2: Exchange the public keys.
3. Step 3: Encrypt the message using the public key of the Server and send to Server or vice-versa.
4. Step 4: The Server can then use its private key to decrypt the message.

How do you build an end-to-end encryption?

1. What Is End-To-End Encrypted Messaging?
2. Building an Encrypted Chat Messaging Application.
3. Prerequisites.
4. Setup the Backend.
5. User Authenticates With Backend.
6. Step 2: List users.
7. Step 3: Create a Private 1:1 Channel.
8. Step 4: Sending an Encrypted Message.