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3 articles with this tag.
A5/1 protected GSM phone calls for decades. Learn how three small shift registers that move at irregular times produce keystream, why the cipher was kept secret, and how researchers broke it in practice.
15 min read
E0 is the stream cipher that has protected Bluetooth connections since the late 1990s. Learn how four shift registers and a tiny state machine produce keystream, how the session key and clock are loaded, and why E0 is now considered broken.
20 min read
Grain pairs a linear shift register with a nonlinear one and filters them into a keystream. Learn how Grain v1 and Grain-128 work, why they were designed for tiny hardware, and what attacks have taught designers about them.
16 min read
