Showing papers on "Attribute-based encryption published in 1994"

Space requirements for broadcast encryption

Abstract: Fiat and Naor [5] presented at Crypto '93 a new encryption scheme designed for broadcast transmissions. The feature of this scheme is to allow a central broadcast site to broadcast secure transmissions to an arbitrary set of recipients. In this paper we model the problem of unconditionally secure broadcast encryption schemes with an information theoretic framework. We obtain tight limitations both on the number of private keys associated with each user and on the number of keys generated by the center. Finally, we consider the model where interaction is allowed in the common key computation phase proving that the interaction cannot help in decreasing the size of the pieces of information given to the users in the broadcast encryption schemes.

Searching for patterns in encrypted data

Abstract: A searching method determines, given a specified encryption method (or set of encryption methods) and a specified pattern (or set of patterns), whether a given text contains an encryption, with any key, of anything fitting the pattern or patterns. The procedure detects and locates patterns that are present within data that has been encrypted, provided that the encryption method is one of a variety of simple methods that are often employed by computer programs such as computer viruses. The method includes: 1. applying an invariance transformation to the chosen pattern (or set of patterns) to be matched, to obtain a "reduced pattern"; 2. applying the same reduction to the encrypted data to obtain "reduced data"; 3. using standard string searching techniques to detect the existence of a match between the reduced pattern and the reduced data, thereby signalling the likely existence of the pattern in encrypted form within the encrypted data; 4. corroborating any such likely matches by using techniques specialized to the particular form of encryption; and 5. providing information about the match. Depending on the nature of the encryption method and the desired degree of certainty about the match, item 4 may not be necessary. In one embodiment, the patterns and an indication of the encryption method(s) for which they are appropriate are incorporated into the database of a computer virus searcher. The searcher applies each of several different invariant transformations to the searched data (one for each encryption method of interest), and uses search techniques, such as parallel search techniques currently employed by virus searchers, to detect any patterns that may be encrypted within the searched data.

Dual key reflexive encryption security system

Abstract: A security system is disclosed, which system is for granting access to a host computer in response to a demand from a remote computer. The security system has a permanent encryption key mounted on the remote computer. The software portion of the system provides for the identification number associated with the permanent encryption key to be sent unencrypted to the host computer. Using the identification number the host computer selects an encryption device and encrypts a transitory encryption key generated by the host computer and transmits the transitory encryption key to the remote for emplacement on a write-only receptor in the permanent encryption key. Thereafter a comparator in the host computer, in response to encrypted identifying data transmitted from the remote computer and encrypted with said the transitory encryption key, authenticates the access demand. Access is granted by the host computer to the remote computer upon the favorable comparison of an encrypted identifier provided by the remote computer.

Key management for large scale end-to-end encryption

Abstract: The Digital Signature Standard (DSS), which has been adopted by the United States Government, has both public and private components, similar to a public-key cryptosystem. The Digital Signature Algorithm of the DSS is intended for authenticity but not for secrecy. The authors show how the use of the Digital Signature Algorithm combined with both symmetric and asymmetric (public-key) encryption techniques can provide a practical solution to key management scaleability problems, by reducing the key management complexity to a problem of order N, without sacrificing the encryption speed necessary to operate in high performance networks. >

Multifeature Security through Homomorphic Encryption

Abstract: After the announcement of a U.S. digital signature standard by NIST, the role of the Exponential One Way Function — which had been used in the initial illustration of public key cryptography — has again received proper recognition as being another security primitive in addition to the RSA-scheme.