Prekey Bundles: How Encrypted Chat Works When You're Offline
How prekey bundles let encrypted chat work when the recipient is offline: what they contain, how a sender derives a shared secret alone, and the key-substitution risk.
X3DH, Explained: The Handshake Behind Asynchronous Encryption
How X3DH lets two people share an encryption key when one is offline — the four Diffie-Hellman operations, what each provides, and the post-quantum upgrade.
Harvest Now, Decrypt Later: Why Post-Quantum Encryption Already Matters
An adversary who records your encrypted traffic today can wait years to decrypt it. Why long-lived secrets need post-quantum protection now, and how hybrid X25519 + ML-KEM-768 delivers it.
The Quantum Clock Just Moved: Google Shrinks the Cost of Breaking ECC
A March 2026 Google Quantum AI paper estimates that breaking 256-bit elliptic-curve cryptography needs ~1,200 logical qubits and under 500,000 physical ones — an order-of-magnitude drop. The machine still doesn't exist. Here's what that actually means for your encrypted messages.