Exercises

Every exercise from the courses, in one place. Search for a specific one, filter by subject, or let chance pick one for you.

Random exercise

Flash questionsShort drills on core skills, as cards to project or print.See the series

1120 exercises

Limit of a sequence

Mathématiques – Suites3 exercises

Short answerAdvanced

Calculating the limit of a rational sequence

A monotonous and narrow-minded sequence

Open answerAdvanced

Proof using the ‘policemen’s theorem’

Modular arithmetic, the foundation of cryptography

Cryptographie – Mathématiques4 exercises

Short answerIntermediate

Reduce modulo n

MCQIntermediate

Existence of the inverse

Short answerIntermediate

Modular exponentiation

Open answerIntermediate

Why reduce at every stage?

Public-key cryptography and RSA

Cryptographie – Clé publique4 exercises

The role of the two keys

Open answerAdvanced

The problem of scale

Short answerAdvanced

Calculate φ(n) for an RSA key

RSA Security

Hash functions and digital signatures

Cryptographie – Intégrité4 exercises

Properties of hashing

Open answerAdvanced

Why add salt and slow things down?

What a signature guarantees

Short answerAdvanced

Which key should I use to sign?

Secret codes: encryption and decryption

Cryptographie – Fondamentaux4 exercises

Understanding Kerckhoffs

Short answerBeginner

Deciphering a Caesar cipher

Why the substitution fails

Open answerBeginner

Attacking a short message

Vigenère and the early days of cryptanalysis

Cryptographie – Fondamentaux4 exercises

Short answerIntermediate

Encryption using the Vigenère cipher

MCQIntermediate

Vigenère’s contribution

MCQIntermediate

The terms and conditions for disposable face masks

Open answerIntermediate

The paradox of the disposable mask

The states of matter and changes of state

Chimie – La matière1 exercise

Identifying a change of state