Abstract: The invention concerns a method for guaranteeing certification of a user's public key by reducing requests to key-certifying appropriate authorities. More particularly, the invention concerns a method for managing a public key of a user capable of being implemented in an asymmetric cryptosystem. According to the invention, a certification, or validation of the correspondence between a public key and a user, is performed by a validating entity, a provider separate from the certifying authority via a validation step. The password is verifiable by the validating entity, but without the latter being aware of it.