摘要:
A method of recording successive balances in an electronic memory constituted by a plurality of memory locations each having an initial state "0" and a final or "written" state "1". The memory includes at least one memory region split into two memory zones, with each of the two memory zones including the same number of memory locations, and with each memory location occupying a rank in an ordered relationship defined in the memory zone to which is belongs, with two memory locations of corresponding rank constituting a pair of memory locations which is likewise distinguished from the other pairs by a rank. Before each recording event, the region includes a single reference pair CR.sub.n-1 having its two memory locations in different states, with the other pairs being constituted by memory locations which are both in the initial state C(O,O) or memory locations which are both in the final state C(1,1). In order to write a new balance S.sub.n corresponding to a number p of units, where possible, the memory location in the reference pair CR.sub.n-1 which was in the initial state "0" is caused to change to the final state "1", and a new reference pair CR.sub.n is written at a rank such that the number NT.sub.n of pairs in the initial state C(O,O) and of rank greater than the rank of the reference pair CR.sub.n is equal to p.
摘要:
Implementations of various technologies for a method for establishing communication pathway redundancy within a seismic recording array. In one implementation, the method may include identifying each data acquisition cell deployed in a seismic field and determining one or more communication pathways for each data acquisition cell. The communication pathways include a primary communication pathway and at least one backup communication pathway toward a data collection unit. The method may further include transmitting the communication pathways to each data acquisition cell deployed in the seismic field
摘要:
A method and apparatus for protecting a selective access system against fraudulent use of a magnetic card having a confidential card. Each cade (CM) is associated with a class corresponding to a zone of a memory (PROM). The number of classes is equal to the number of zones and is substantially less than the number of cards (CM) which may be presented. At each failure to input a confidential code, one of the bits is modified in the corresponding memory zone.
摘要:
The method in suitable for authenticating electronic memory cards intended for authorizing the supply of goods or services after being processed by a card reader machine. The card memory includes at least three zones (Z.sub.1, Z.sub.2, Z.sub.3) comprising a first zone (Z.sub.1) which is readable from outside and which contains information (I) and a corresponding signature (S) obtained by means of secret data (D) recorded in the third zone (A.sub.3) which cannot be read from outside the card. The second zone (Z.sub.2) which can be read from outside the card contains the result of secret key and public key encoding all of the data contained in the first zone. This method provides effective protection against several types of fraud.