摘要:
A method and system for the secure transmission of messages between at least two users of a telecommunications network, using a secret, random binary encryption key, which is used once for encryption. The key is generated in a key generator recorded on at least two portable data media, such as CDs, and then output in this form to the users, each of whom receives one data medium containing the recorded key. The key is not stored in any other location. The users insert the recorded key media into reading devices, which are respectively assigned to telecommunications equipment, e.g., telephones, fax machines, or PCs, employed by the users. When a connection is established, logistics devices, which are also assigned to the telecommunications equipment, check whether the keys were entered properly and whether they correspond to each other. The logistics devices also synchronize the entered keys, or at least portions of the keys, when the information to be transmitted is encrypted and decrypted.
摘要:
A method and an apparatus for generating a random number on a quantum-mechanics machanics basis using the fundamentally random choice of path of a quantum particle on a beam splitter. Detectors are provided for capturing the particles being assigned to the outputs of the beam splitter. The detectors or their counting events represent different number values of the random number, or random number sequence. The generation of a multi-particle state in the output channel of the beam splitter, and thus of several particles which impact on a detector (D1, D1′, D2, D2′), significantly and advantageously increases the response probability of the detector and thus the probability of obtaining a useable counting event for every multi-particle state generated by the particle source. In this way a random sequence can be obtained more rapidly and more reliably than with single-particle detection.
摘要:
A method for electronically compressing and decompressing digital data using a context grammar includes grammatically compressing first digital data by discovering multiply occurring sequences of non-further-factorizable terminal symbols in the first digital data and replacing the discovered multiply occurring sequences of non-further-factorizable terminal symbols with non-terminal symbols that can be further factorized. Digital data belonging to the non-terminal symbols is stored in a context grammar. Second digital data is compressed using the context grammar. The first digital data relates to a column of data stored in a database and the second digital data relates to entries in the column of data stored in the database.
摘要:
A method and arrangement for generating binary sequences of random numbers uses the principle of random selection of the path of photons on a beam splitter and generating a random number by using two detectors (D10, D21) downstream from a beam splitter (ST2). To generate photons, a light source (L) of a low power is used, and an additional beam splitter (ST1) is connected upstream from the beam splitter (ST2). The photons emitted by the light source (L) during a predefined measurement time are split by the beam splitters (ST1, ST2) arranged one after the other in the beam path of the light source (L). The random sequence is generated when the splitting of the photons matches a predefined photon scheme.
摘要:
A quantum cryptography system using electrooptical liquid crystal modulators which change the polarization and which are designed as electrically rotatable retardation plates whose two birefringent axes are rotated by the applied electrical field around an angle &thgr; which depends on the strength of this field. A &lgr;/2 retardation plate rotates the elliptically polarized light striking the plate around an angle 2&thgr; at speeds in the microsecond range. The quantum cryptography system can be used for interception-proof data transmission over transmission links that are accessible to the public.