Secure communication system

• US 5,671,285 A
• Filed: 12/13/1995
• Issued: 09/23/1997
• Est. Priority Date: 12/13/1995
• Status: Expired due to Fees

• Current Assignee: Bruce D. Newman
• Original Assignee: Bruce D. Newman
• Inventors: Newman, Bruce D.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/571,503
• Time in Patent Office: 650 Days
• Field of Search: 380/4, 380/9, 380/18, 380/30, 380/49, 380/50, 380/23, 380/24, 380/25
• US Class Current: 705/78
• CPC Class Codes: G06Q 20/0855 involving a third party
• CPC Class Codes: G06Q 20/382 insuring higher security of transaction
• CPC Class Codes: G07F 17/26 for printing, stamping, franking, typing or teleprinting apparatus ticket printing or the like apparatus G07F17/42
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps
• CPC Class Codes: H04N 1/4406 Restricting access, e.g. according to user identity mechanisms actuated y cards, PIN or the like in apparatus for dispensing G07F7/08
• CPC Class Codes: H04N 1/4426 involving separate means, e.g. a server, a magnetic card
• CPC Class Codes: H04N 1/4486 using digital data encryption

Abstract

Encryption/decryption capable terminal units, such as FAX point-of-sale units, on non-secure telecommunications, use public keys for accessing selected target terminals, but make their messages secure by encryption according to private keys. Each subscriber terminal registers, with a central database controller, a unique public key code. Each terminal includes a quick-access storage for a finite number of telephone numbers and related public keys for other terminals. To send a message, the source FAX first queries its local storage for the public key of the target terminal. If the public key is present, it sends a message encrypted with the public key for the target terminal, along with a digital signature. When the message is transmitted, the encrypted public key for the target terminal, and the digital signature of the source terminal user'"'"'s private key are combined to form a message packet for decryption by the target terminal. The target terminal queries its own key storage to permit decrypting using its own private key and the public key of the sender. The central database controller provides unknown telephone numbers and public keys, and archives, groups, forwards and timestamps messages, and authorizes credit card transactions, without forwarding credit card numbers and without capability to decrypt such message. Credit transactions require the central database controller to communicate separately with the credit provider, but these messages may be similarly encrypted using the public key and private key concept.

Claims

1. An encryption/decryption secure system for communication, via non-secure telecommunications, between a multiplicity of send/receive terminal units, comprising:

a) a central database controller having a stored database, of access numbers indexed to public keys, for a full set of subscriber terminal units;

b) a multiplicity of possible target terminal units at potential target locations, including a set of 1 to (n) to-be-selected target terminal units at respectively related selected target locations, each potential target terminal unit having an associated public key and associated private key respectively for access and encryption/decryption;

c) a multiplicity of terminal units which are potential source units positioned at remote locations, including a source terminal unit at a source location, each local potential source terminal unit, including said source terminal unit, having an access number, an associated public key and an associated private key for access and encryption/decryption, said source terminal unit comprising;

c.1) local quick-access storage means for storing a subset of said database of access numbers indexed to public keys of potential target terminal units;

c.2) local means to query whether or not a selected target terminal unit, indexed by access number to an associate public key, is present in said local quick-access storage means, and to provided a quick-access determination indication; and

c.3) means responsive to the quick-access determination indication of said local means to transmit timely to the selected target terminal unit, and alternatively to request from said central database controller the public key indexed to the access number of said target terminal unit.

2. An encryption/decryption secure system for communication, according to claim 1, which system operates in a plurality of communication modes, further comprising in said control means (c.2) of said selected source terminal unit:

c.2.1) communication mode identification means, to cause transmission of a selected communication mode identification signal to said target terminal unit and to control transmission of subsequent related data to said selected target terminal unit according to the communication mode of said selected communication mode identification signal; and

c.2.2) said potential target terminal units have means to process said subsequent related data according to said selected communication mode identification signal.

3. An encryption/decryption secure system for communication, according to claim 2, in which said communication control means (c.2) controls transmission of a mode identification signal which calls for encryption, and controls transmission of the related message in encrypted form.

4. A security encryption/decryption system communicating via non-secure telecommunication lines according to claim 3, further characterized in that said central database controller operates to timestamp and forward an encrypted message without capability to decrypt such message.

5. A security encryption/decryption system communicating via non-secure telecommunication lines according to claim 3, further characterized in that said central database controller operates automatically to carry out a subset of functions from the function set of timestamp, archive, group and forward an encrypted message without capability to decrypt such message.

6. An encryption/decryption secure system for communication, according to claim 1, which system operates in a plurality of communication forms, further comprising in said control means of said selected source terminal unit:

c.2.1) communication mode identification means, to cause transmission of a selected communication mode identification signal to said database controller and to said target terminal unit and to control transmission of subsequent related data to said selected target terminal unit according to the communication mode of said selected communication mode identification signal; and

c.2.2) said potential target terminal units have means to process, including decryption, said subsequent related data according to said selected communication identification signal and said database controller having means except for decryption to process said subsequent related data according to said selected communication mode identification signal.

7. An encryption/decryption secure system for communication, via non-secure telecommunications, between a multiplicity of send/receive terminal units, according to claim 1, further characterized in that said central database controller operates to verify an encrypted credit card number and amount message from a source terminal by automatic communication with a credit database, and authorize the transaction to a selected target terminal unit, without forwarding the credit card number to said selected target terminal unit and without capability to decrypt such message.

8. An encryption/decryption secure system for communication, via non-secure telecommunications, between a multiplicity of send/receive terminal units, according to claim 7, further characterized in that said central database controller operates while said source terminal unit and said selected target terminal unit remain connected on a communication channel, to authorize a credit card transaction between said source terminal and said selected target terminal without the decrypted credit card number being made available to said selected target terminal or to said computer network.

9. In a secure system for communication via non-secure telecommunications, between a multiplicity of terminal units a security subsystem which operates in a plurality of communication modes, such security subsystem comprising:

a) a central database controller having a stored database, indexed to access numbers to retrieve public keys for a set of subscribers;

b) a multiplicity of potential target terminal units at potential target locations, including a to-be-selected target terminal unit at a selected target location, each potential target terminal unit having an associated public key and a private key respectively for access and encryption/decryption;

c) a multiplicity of terminal units, some of which may be potential target terminal units, which are potential source terminal units positioned at remote locations, including a source terminal unit at a source location, each local potential source terminal unit, including said source terminal unit, having an access number, an remote public key and an associated private key respectively for access and encryption/decryption, said source terminal unit comprising;

c.1) local quick-access storage means for storing a subset of said indexed database of access numbers for public keys of potential target terminal units; and

c.2) local control means to determine whether or not a selected target terminal unit access number for its public key is available to said local quick-access storage means, said local control means further comprising;

c.2.1 communication mode identification means, to cause transmission of a selected communication mode identification signal requiring encryption and to control transmission of a related message to said selected target terminal unit encrypted according to the communication mode of said selected communication mode identification signal; and

c.3) means responsive to said local control means, to determine whether to transmit directly to the selected target terminal unit.

10. A security encryption/decryption system communicating via non-secure telecommunications, among a multiplicity of send/receive terminal units, comprising:

a) a central database controller (2) having an indexed database, of access numbers for public keys, for a full set of subscriber terminal units;

b) a multiplicity of potential target terminal units at potential target locations, including a set of 1 to (n) to-be-selected target terminal units at respectively related selected target locations, each potential target terminal unit having an associated public key and associated private key respectively for access and encryption/decryption;

c) a multiplicity of potential source terminal units positioned at respectively related locations, including a source terminal unit at a source location, each local potential source terminal unit, including said source terminal unit, having an access number, an associated public key and an associated private key for access and encryption/decryption, said source terminal unit comprising;

c.1) local quick-access storage means for storing a subset of said database of access numbers indexed to public keys of potential target terminal units;

c.2) local means to query whether or not a selected target terminal unit, indexed by access number to an associate public key, is present in said local quick-access storage means, and to provided a quick-access determination indication; and

c.3) means responsive to the quick-access determination indication of said local means to transmit directly to the selected target terminal unit, and alternatively to request from said central database controller the public key for the access number of said target terminal unit.

11. A security encryption/decryption system for communication between a multiplicity of FAX terminal units communicating via a non-secure communication system, characterized by a central database controller having stored a set of subscriber identifiers, each including the telephone numbers indexed to public keys for a full set of subscribers, said multiplicity of FAX terminal units including at least one source FAX unit at a source location and a multiplicity of potential target FAX units at other locations, including at least one selected target FAX unit, each potential target FAX unit including said target FAX unit having an associated public key and a private key respectively for access and encryption/decryption, all such source and potential target FAX units being connectable to each other and to said central database controller (2), said source FAX unit having a frequently-called-subscriber-list storage means for a subset of said set of subscriber identifiers, each including the telephone numbers for public keys of potential target FAX units, said source FAX unit having means to determine whether a selected target FAX unit subscriber identifier is stored in said frequently-called-subscriber-list storage means, and said source FAX unit having means to query said central database controller with the telephone number for the public key of a selected target FAX unit to provide the subscriber-identifier public key for a telephone number not present in said frequently-called-subscriber-identifier list storage means, further characterized by the deployment in the system of a plurality of levels of security including a encryption-level-of-security-identification when encryption is desired, each of said levels of security being identifiable by a level-of-security-identification signal, in which the source FAX unit transmits a level-of-security-identification signal along with a selection of target FAX unit and transmits a message to said selected target FAX unit according to said selected level-of-security-identification, in which said encryption-level-of-security-identification requires the message to be transmitted in encrypted mode, and in which said central database controller operates to provide additional services in the group of services comprising grouping, broadcasting, remote save, remote time stamping, archiving and billing, and forwarding an encrypted message without capability to encrypt such message.

12. The method for making a secure credit card transaction on a non-secure communication channel, including the following steps:

Step 1--Customer C and merchant M confer on non-encrypted communication channel to place an order for items;

Step 2--Merchant M sends to customer C a data group including order identification number, total price, and the public key of the central database;

Step 3--Customer C sends back to merchant M a data group including order identification number plus an encrypted data group including total price, order identification number and credit card information, using the CDB public key, Note;

Merchant M cannot decrypt this encrypted data group;

Step 4--Merchant forwards to central database the complete message, minus the non-encrypted order identification number from Step 3;

Step 5--Central database queries credit availability from a credit provider, using its own secure or dedicated communication channel, and where establishes the validity of the credit transaction for the particular purchase order, or invalidity;

Step 6--Central database sends back to merchant M, possibly encrypted, with a OK or Nay for the order plus total dollar amount and order identification number;

Step 7--Merchant M transmits OK or NAY for the order back to customer C, who has remained on line.