Method for retrieving data entered during a server connection, the server having access to a memory including a generated hashed word of a first input data, which corresponds to the data modified by a processing function, the capacity of the hashed word being lower than a predefined capacity, a generated security key of a second input data, which corresponds to the data modified by a processing function, the capacity of the security key being equal to the difference between the predefined capacity and the hashed word capacity, the security key not being stored, method wherein: —after a request to retrieve the data, the hashed word and the security key are concatenated in order to reach the predefined capacity, and —an inverse hash function, using an algebraic solving of the hash function, is applied to the concatenation of the hashed word and security key, to retrieve the data.