Caller identification system with encryption
US5289542A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 4, 1991 |
| Grant date | Feb 22, 1994 |
| Priority date | — |
| Expiry date | Mar 4, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q2213/13339
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Telephone call identification service that safeguards the privacy of an originating station (calling party), while providing useful identifying information to a destination station (called party), is achieved by an encryption process. The encryption process includes combining the originating number with the telephone number of the destination station to form a message. Thereafter, the message is encrypted using the Data Encryption Standard (DES) or the Rivest, Shamir, Adleman (RSA) encryption algorithm to form ciphertext which is transmitted to the destination station. Using either encryption process, the ciphertext is reversible. A telephone switching office, preferably equipped with an electronic program-controlled switching system, executes the encryption algorithm and safeguards the keys used for encryption and decryption. When reversibility of the ciphertext is deemed to be undesirable, the telephone switching office uses modulo n processing of the ciphertext to render it non-reversible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.