procedures to verify the integrity and authorship and the encryption and decode of texts

摘要

In a method concerning the verification of the integrity and authorship of a text is revealed based on the use of a tripartite electronic signature: the tripartite electronic signature consists of a token (K), identifying the author of the text, a hash value of the text called its "text seal" (S) that is calculated from the characters of the text and their disposition with a public one-way algorithm, and the so called "signature proof" (U) calculated from S with a private one-way algorithm, dependent on a secret code G. The tripartite electronic signature replaces a hand written personal signature. For verification, the tripartite electronic signature is sent to an autonomous module, where its three numbers are analysed. As the result, the verifying person receives the message: signature is valid or not valid. In order to be able to perform this analysis, the module contains a data bank which stores the secret codes G of all the participants marked with their token K. Entering a specific token K of a participant in the data bank releases his/her secret code G for the recalculation of the signature proof U from the text seal S with the private one-way algorithm. The newly calculated U is compared with its counterpart in the tripartite electronic signature as entered in the module. This enables the module to release the above mentioned message. A trustworthy instance supervises that only such value pairs (secret code G and token K) can be entered in the data bank, whose owners have proved their identity and the relevance of their token K to that identity. By means of a symmetric cipher dependent on the secret code G, attributed to all participants and to the module, texts can be encoded by their author, sent to the module, decoded and re-encoded in the module, sent to the addressee, and decoded by the latter.