Fermat's little theorem

E146189

Fermat's little theorem is a fundamental result in number theory that characterizes how prime numbers interact with integer powers modulo that prime, forming the basis for many modern cryptographic algorithms.

All labels observed (2)

Label Occurrences
Fermat's little theorem canonical 1
Fermat’s little theorem 1

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Statements (46)

Predicate Object
instanceOf result in number theory
theorem
appliesTo finite fields
modular arithmetic
assumption p is greater than 1
category elementary number theory
condition a is an integer
gcd(a,p) = 1 for the form a^(p−1) ≡ 1 (mod p)
p is a prime number
failsFor composite moduli in general
field number theory
generalizedBy Euler’s theorem
surface form: Euler's theorem
hasConsequence existence of multiplicative inverses modulo a prime
structure of the multiplicative group modulo a prime is cyclic of order p−1
hasVariant exponent p form
exponent p−1 form
historicalPeriod 17th century mathematics
implies a^(p−1) − 1 is divisible by p when gcd(a,p)=1
p divides a^p − a for any integer a
importance basic result taught in undergraduate number theory
fundamental tool in modern public-key cryptography
isPartOf classical results on primes
languageOfOriginalFormulation Latin
namedAfter Pierre de Fermat
proofTechnique combinatorial arguments
group theory
induction on exponents
relatedConcept Carmichael number
Fermat pseudoprime
relatedTo Chinese remainder theorem
Euler’s theorem
surface form: Euler's theorem

Wilson's theorem
statement For any integer a and prime p, a^p ≡ a (mod p).
If p is a prime and a is an integer not divisible by p, then a^(p−1) ≡ 1 (mod p).
topic congruences
multiplicative group of integers modulo p
properties of prime numbers
usedFor computing modular inverses when modulus is prime
simplifying large exponent computations modulo a prime
usedIn Diffie–Hellman key exchange
ElGamal
surface form: ElGamal encryption

Fermat primality test
RSA
surface form: RSA cryptosystem

cryptography
modular exponentiation algorithms
primality testing

How these facts were elicited

Referenced by (2)

Full triples — surface form annotated when it differs from this entity's canonical label.

Pierre de Fermat notableWork Fermat's little theorem
Euler’s theorem generalizes Fermat's little theorem
this entity surface form: Fermat’s little theorem