Computer security
What are you protecting?
What could get through?
Follow one attack, change one protection, and see what still needs attention. Start with an everyday account. Then explore keys, recovery and shared control in the existing blockchain lessons.
Choose a chapter · 1 available
A stronger sign-in is one part of account security.
Chapter 1
Account security: what stops which attack?
Compare a stolen password, a fake sign-in page and a stolen signed-in session. Try passwords, one-time codes and passkeys, then inspect what each control leaves exposed.
Open the chapterThe chapter uses fictional scenarios. It does not test your accounts or ask for real passwords, recovery codes or keys.
Fingerprints and tamper evidence
Existing blockchain lessons introduce hashes and show the assumptions behind a linked record.
What is a hash?
Change a message and inspect its fingerprint. Explore a small PIN search and why a hash is not encryption.
Blocks & chains
Edit a record and follow the broken links. See why recalculating hashes alone does not establish agreement.
Consensus & proof of work
Explore a simplified catch-up race with explicit hashpower and starting-deficit assumptions.
Keys, recovery and shared control
These are blockchain-specific lessons. A wallet signature and a website sign-in serve different purposes.
Wallets, keys & signatures
Sign a demonstration message and check what changes when the message or key changes.
Mnemonics & seed phrases
Explore recovery words, checksums and the consequences of exposing a wallet backup.
Hot & cold wallets
Compare key exposure and signing steps. Try a blind-signing trap and a simulated offline signing ceremony.
Multisig: many keys, one vault
Lose demonstration keys and inspect a signing threshold. More participants add coordination and recovery work.
MPC: signing without reassembly
Separate secret sharing from threshold signing and inspect the limits of each model.
Signing scenario
Change participant availability and approval policy independently. This illustrative model performs no cryptography or asset transfers.
A tool with a specific job
Use the result for the property it checks.
From the archive
Historical blockchain writing, with dated context. These are reading links, not additional computer-security chapters.
Storing declarations on Trivechain
A retrospective on a 2019 demonstration and the difference between demonstrating a mechanism and relying on its network security.
Blockchain applications and randomness
Archived writing with a later correction explaining why block hashes alone are not a general guarantee of unbiased game randomness.