Method of integrity verification of public and private cryptographic key pairs in the additive group of integers modulo n, with n being the product of two prime numbers p and q, the method including the following steps: of computation (201), on the basis of the number n, of a public exponent e of the public key, and of a private exponent d of the private key, of two candidate factors p′ and q′ corresponding respectively to the numbers p and q, of verification (206) so as to verify the consistency of the private exponent with respect to the public exponent and to the number n, the verification step involving the candidate factors.