End-to-End Encrypted Key Exchange

System Design diagram · made in Skemio

Cryptographic architecture depicting Alice requesting Bob's pre-key bundle from a key server, establishing a shared secret, and sending Double Ratchet encrypted messages.

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What it shows

X3DH creates shared secrets using pre-published public key bundles
The server routes ciphertext without accessing private key halves
The Double Ratchet derives new ephemeral keys for each message

The takeaway

Pre-key bundles initiate sessions offline; the double ratchet guarantees forward secrecy and break-in recovery.

#Cryptography
#EndToEndEncryption
#SystemDesign
#CyberSecurity
#DataPrivacy
#SoftwareEngineering

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