Foundations

What Is Encryption?

Encryption hides a message’s contents. See how encryption and decryption work with a simple locked-box example.

What Is an Encryption Key?

An encryption key is a digital value that controls how data is locked or unlocked. Learn why a secret key needs protection.

What Is Public-Key Cryptography?

Public-key cryptography uses a pair of keys: one you share and one you keep private. Learn the role of each key.

What Is a Digital Signature?

A digital signature checks a message against a signing key and detects changes. Learn what it proves and what it does not.

Cryptography basics: the pieces the quantum threat rearranges

Symmetric ciphers, hashing, key exchange, and digital signatures: the four building blocks of secure communication, and which of them a quantum computer actually threatens.

What Is a Quantum Computer?

A quantum computer uses quantum physics to calculate differently. Learn why it helps with particular problems, not every task.

What Is a Qubit?

A qubit is a unit of quantum information. Learn why measuring it in the zero-or-one basis gives one result, not every possibility.

How Many Qubits Would It Take to Break RSA?

A qubit count alone cannot tell you whether a machine could break RSA. Errors, error correction and running time also matter.

Is AES-256 Quantum Safe?

Correctly used AES-256 resists known quantum attacks. Learn why its secret key and the way that key is exchanged still matter.

Can Quantum Computers Forge Digital Signatures?

A sufficiently capable quantum computer could recover some private signing keys. Learn how that would allow a forged signature.

Can Quantum Computers Steal Bitcoin?

A sufficiently capable quantum computer could threaten vulnerable Bitcoin spending signatures. Learn the conditions behind the risk.

Can AI Break Encryption?

AI is not a known general shortcut through strong encryption. Learn the difference between breaking the mathematics and stealing a key.

Shor vs Grover: what breaks and what only weakens

Two quantum algorithms define the whole threat. Shor's breaks public-key cryptography outright; Grover's only weakens symmetric crypto, and is answered by using longer keys.

PQC algorithm families: lattice, hash-based, and the ones that failed

Post-quantum cryptography is built on different hard problems than RSA. Here are the main families, the NIST-standardized algorithms, and why some contenders were broken along the way.

Crypto-agility and hybrids: changing algorithms without a rewrite

The most durable outcome of a post-quantum migration is not any single algorithm but the ability to swap algorithms easily, and hybrids are how you deploy new ones safely in the meantime.