Abstract: At least one expired decryption key intended to be used for asymmetrical decryption of encrypted data is recovered in a terminal after generation of a cryptographic encryption key/decryption key pair stored in a cryptographic medium such as a microchip card. The expired decryption key is stored in a database accessible to a user of the terminal and encrypted beforehand as a function of the new generated encryption key. In the terminal connected to the cryptographic medium, the encrypted expired encryption key is decrypted as a function of the decryption key stored in the cryptographic medium so that the encrypted data is decrypted as a function of the thus decrypted expired decryption key.