Quantum Computing & Encryption for Beginners
One question at a time: see how encryption works, what quantum computers change, and how post-quantum security helps. Start at the beginning or choose the question you have now.
16 lessons · 22 minutes of video · Free
Start the first lessonChoose a question
Follow the order below or jump straight to a topic. Open each guide to watch, read and check your understanding.
What Is Encryption?
Encryption hides a message’s contents. See how encryption and decryption work with a simple locked-box example.
Video · 1:15 and guide
What you will learn
Encryption hides the contents of a message; decryption makes it readable again.
Open the full lesson →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.
Video · 1:20 and guide
What you will learn
A key is the value that controls an encryption operation; the example uses one shared secret key.
Open the full lesson →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.
Video · 1:17 and guide
What you will learn
A public key can be shared while its matching private key is kept secret.
Open the full lesson →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.
Video · 1:13 and guide
What you will learn
A digital signature checks a message against a signing key and detects changes.
Open the full lesson →What Is a Quantum Computer?
A quantum computer uses quantum physics to calculate differently. Learn why it helps with particular problems, not every task.
Video · 1:18 and guide
What you will learn
A quantum computer uses quantum physics to compute in a different way and is useful for particular problems.
Open the full lesson →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.
Video · 1:16 and guide
What you will learn
A qubit can have a superposition state, but measuring it in the described way returns one bit.
Open the full lesson →Can Quantum Computers Break Encryption?
A sufficiently capable quantum computer could break some public-key methods. Learn why this does not mean all encryption fails.
Video · 1:24 and guide
What you will learn
A sufficiently capable quantum computer threatens some encryption methods, not all of them.
Open the full lesson →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.
Video · 1:24 and guide
What you will learn
An RSA attack estimate needs a qubit type, error assumptions and a runtime, not just a count.
Open the full lesson →What Is Harvest Now, Decrypt Later?
An attacker can save encrypted information now and try to read it later. Learn why long-lived secrets need protection in advance.
Video · 1:21 and guide
What you will learn
An attacker can save encrypted information now and try to read it after its protection can be broken.
Open the full lesson →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.
Video · 1:31 and guide
What you will learn
Known quantum attacks do not make correctly used AES-256 practical to break.
Open the full lesson →What Is Post-Quantum Cryptography?
Post-quantum cryptography runs on ordinary computers and is designed to resist ordinary and quantum attacks. Here is the basic idea.
Video · 1:24 and guide
What you will learn
Post-quantum cryptography uses methods designed to resist both ordinary and quantum attacks on ordinary computers.
Open the full lesson →What Is Hybrid Key Exchange?
Hybrid key exchange combines traditional and post-quantum methods to establish a shared secret. Learn why the combination matters.
Video · 1:24 and guide
What you will learn
A suitable hybrid construction combines secrets from two methods so confidentiality can survive failure of one method.
Open the full lesson →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.
Video · 1:27 and guide
What you will learn
A sufficiently capable quantum computer could recover private signing keys for vulnerable signature methods and create forgeries.
Open the full lesson →Can Quantum Computers Steal Bitcoin?
A sufficiently capable quantum computer could threaten vulnerable Bitcoin spending signatures. Learn the conditions behind the risk.
Video · 1:22 and guide
What you will learn
A sufficiently capable quantum attacker could forge spending signatures for exposed, vulnerable public keys.
Open the full lesson →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.
Video · 1:21 and guide
What you will learn
AI-assisted theft or guessing is different from defeating a strong encryption method.
Open the full lesson →What Is Crypto-Agility?
Crypto-agility means changing cryptographic methods while keeping a system working securely. Learn why planning for change helps.
Video · 1:21 and guide
What you will learn
Crypto-agility is the ability to replace cryptographic methods while keeping a system secure and working.
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