Arcot Systems, Inc.

Ca, Inc.

Sanguthevar Rajasekaran

Rammohan Varadarajan

Rajendra Arcot Gopalakrishna

James Donald Reno

Balas Natarajan Kausik

Geoffrey R Hird

Robert A Jerdonek

Sanjay Vyas

Do-Pil Park

A computer-representable object (including, without limitation, a cryptographic key, or a graph or a Boolean description of a system) is secured using a generalized camouflaging technique. The secured object need not be stored in the system, not even in encrypted form. Instead, the technique employs a composition function that regenerates the secured object when one inputs a valid password (which may be any computer-representable information held by a user). By regenerating the secured object each time a valid password is entered, there is no need to store the secured object. If one inputs an invalid password, the technique may generate an incorrect object, such that the user is unable to distinguish this incorrect object from the secured object. If the user tries to use the incorrect object, the user can be exposed as unauthorized, without the user's knowledge that he has been exposed.

Method and apparatus for camouflaging of data, information and functional transformations

The present invention describes techniques for performing searches in an efficient manner while minimizing the memory resources required to perform the searches. According to the techniques of the present invention, the number of comparisons needed to determine if a query element is in included in a set of elements is proportional to the length of the query element and independent of the number of elements in the set of elements.

Efficient searching techniques

Techniques for efficiently searching encrypted searchable spaces. For example, embodiments of the present invention provide techniques for searching a plurality of files that are stored in encrypted (or ciphertext) form. According to embodiments of the present invention, the search can usually be performed by decrypting only a portion of the encrypted searchable space. According to an embodiment of the present invention, the search techniques determine a set of files comprising one or more files from the plurality of encrypted files that contain a user-specified query element. The set of files is usually determined by decrypting only a subset of the plurality of encrypted files.

Techniques for searching encrypted files

Method and system for camouflaging access-controlled data

An n person secret sharing solution computes n unique keys to be distributed to the secret owners along with an exponentiated version of the secret. The custodian performs an exponent/modulo operation each time one of the keys is received from one of the secret owners. Alternatively, n+1 keys are created by the custodian, and the custodian retains one key after distributing the remaining n keys to the secret owners. After the custodian has received and processed the n keys from the secret owners, he performs an exponent/modulo operation using his own retained key. According to another aspect, a k out of n secret sharing solution involves computing and storing a database having an entry for each unique combination of k keys that could be returned from among the n keys. After k keys have been received, the custodian looks up in the database the entry corresponding to the particular unique combination of secret owners who returned keys. The custodian performs another exponent/modulo operation using the entry retrieved from the database in order to reconstruct the original secret. According to an embodiment, the custodian computes n+1 keys, distributes n of the keys to the secret owners, and keeps one of the keys for himself. The custodian retrieves his own key and performs a final exponent/modulo operation in order to reconstruct the original secret. According to another aspect, a k out of n secret sharing solution involves encrypting the original secret before applying any conventional k out of n secret sharing solution.

Efficient techniques for sharing a secret

Techniques are disclosed to increase the efficiency of multi-party authentication communications protocols. One technique includes a four party authentication method utilizing a general authenticator to store and provide a credit card authentication password and other payment information to an issuing bank and/or other parties involved in the transaction. Other techniques include the use of skeleton messages to minimize the forwarding of information through a forwarding party, the elimination of redundant communications exchanges, the use of a merchant appliance hardware solution to minimize system integration difficulties, and/or the imposition of credit card constraints. The techniques may be used singly or in combination.

Enhancements to multi-party authentication and other protocols

Searching is an important problem that arises in a variety of applications, particularly for computerized databases. Further, many such applications involve searching set of (possible very large) integers (e.g., credit card numbers, employee identifiers, customer identifiers, dates, parts numbers, etc.). We present techniques for integer searching in a computer database based on a improved form of hashing which we shall refer to as 'size-dependent hashing.' This technique can be used to strike a balance between the available memory in the computer system and the required search time.

Size-dependent hashing for credit card verification and other applications

In an authorization system, access is defined by rules, roles and active rules. These definitions are preprocessed to form a bit array for each of a plurality of roles representing the rules that apply to that role. Once a bit array is calculated or generated for a given user based on that user's roles, the user bit array can be cached so that it need not be regenerated for each time the user requests access to resources. The rules used can either be role-based rules or active rules.

Efficient computational techniques for authorization control

An online transaction is effected between a user system, a merchant system and an issuer system. The user system generates a one-time number (OTN) to use as a card number for a transaction with the merchant. The user system generates the OTN as a function of various parameters and sends the OTN to the issuer and to the merchant. With the issuer communication, the user is first authenticated, so the issuer can associate the received OTN with the user even if the user's identity cannot be fully discerned from the OTN alone. In authenticating the user with the issuer, and possibly other authentications, the user sends the issuer a signed challenge where the challenge is a sequential challenge or a function of a prior challenge provided by the issuer. The issuer responds with an approval/denial message and, in the latter case, includes the next challenge to be used.

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Los Altos, CA, United States of America

Sanguthevar Rajasekaran