Cryptographic Functions Research Articles

Cryptographic limitations on parallelizing membership and equivalence queries with applications to random-self-reductions

We assume wlog that every learning algorithm with membership and equivalence queries proceeds in rounds. In each round it puts in parallel a polynomial number of queries and after receiving the answers, it performs internal computations before starting the next round. The query depth is defined by the number of rounds. In this paper we show that, assuming the existence of cryptographic one-way functions, for any fixed polynomial d(n) there exists a concept class that is efficiently and exactly learnable with membership queries in query depth d(n)+1, but cannot be weakly predicted with membership and equivalence queries in depth d(n). Hence, concerning the query depth, efficient learning algorithms for this concept class cannot be parallelized. We also discuss applications to random-self-reductions and coherent sets.

On plateaued functions

The focus of this article is on nonlinear characteristics of cryptographic Boolean functions. First, we introduce the notion of plateaued functions that have many cryptographically desirable properties. Second, we establish a sequence of strengthened inequalities on some of the most important nonlinearity criteria, including nonlinearity, avalanche, and correlation immunity, and prove that critical cases of the inequalities coincide with characterizations of plateaued functions. We then proceed to prove that plateaued functions include as a proper subset all partially bent functions that were introduced earlier by Claude Carlet (1993). This solves an interesting problem that arises naturally from previously known results on partially bent functions. In addition, we construct plateaued, but not partially bent, functions that have many properties useful in cryptography.

Smart card technology for deploying a secure information management framework

The continuously increasing need for de‐centralized information systems offering data to the people who need them irrespective of their physical location, as well as the requirement for exchanging information between different but interoperable systems, make the system’s architectural and functional design more complex and in many cases extremely vulnerable in respect to its security attributes. The concept of a “secure portable information file”, that can nowadays be easily implemented through the available smart card technology, can significantly ease information management and ensure maximum data protection in respect to their integrity, confidentiality and availability. This paper presents the use of smart cards in an educational environment as a case‐study example for demonstrating the above mentioned benefits, focussing on the utilization of the smart card’s cryptographic functions for implementing mechanisms capable of providing an extremely secure operational framework in terms of user and application provider authenticity, management of access privileges and data integrity and confidentiality.

S/390 Parallel Enterprise Server CMOS Cryptographic Coprocessor

As the Internet becomes the basis for electronic commerce, and as more businesses automate their data processing operations, the potential for unauthorized disclosure of sensitive data increases. On-line databases are becoming increasingly large and complex. Sensitive data is transmitted on communication lines and often stored off-line. As a result, the efficient, economical protection of enterprise-critical information is becoming increasingly important in many diverse application environments. The protection required to conduct commerce on the Internet, provide data confidentiality, and provide user authentication can be achieved only by cryptographic services and techniques. The high-speed, physically secure IBM S/390® CMOS Cryptographic Coprocessor for S/390 Parallel Enterprise Servers™, together with the IBM Integrated Cryptographic Service Facility (ICSF), an IBM licensed program for the OS/390® operating system, provides the ability to encrypt and decrypt data, generate and manage cryptographic keys, perform PIN operations, and perform other cryptographic functions dealing with data integrity, digital signatures, and key exchange.

Anonymous conference key distribution systems based on the discrete logarithm problem

In 1997, Wu [T.C. Wu, Conference key distribution system with user anonymity based on algebraic approach, IEE Proc. Comput. Digit. Tech. 144(2) (1997) 145–148] proposed a conference key distribution system (CKDS) with user anonymity using algebraic operations. User anonymity is, in which the identities of participants in a conference are anonymous to each other, except for the chairperson. In this article, two CKDSs with user anonymity are proposed. One is a modified one of the Wu’s scheme that uses simple interpolating properties of polynomials to replace the algebraic approach. Both the Wu’s original scheme and our modified one require a one-way hash function to hide the identities of participants and to protect each participant’s common key shared with the chairperson. Both schemes also use the one-way hash function to provide the authentication for the chairperson. Moreover, we propose another scheme which does not use a one-way hash function, but also achieve the same purposes. Compared to the Wu’s scheme, both our schemes require less computing time. The security of the proposed CKDSs is based on the difficulty of computing the discrete logarithm problem as well as the one-way hash cryptographic function assumption. Both schemes are secure against impersonation and conspiracy attacks.

Batch RSA

Number theoretic cryptographic algorithms are all based upon modular multiplication modulo some composite or prime. Some security parameter n is set (the length of the composite or prime). Cryptographic functions such as digital signature or key exchange require O(n) or O(?n) modular multiplications ([DH, RSA, R, E, GMR, FS], etc.).This paper proposes a variant of the RSA scheme which requires only polylog(n) (O(log2 n)) modular multiplications per RSA operation. Inherent to the scheme is the idea of batching, i.e., performing several encryption or signature operations simultaneously. In practice, the new variant effectively performs several modular exponentiations at the cost of a single modular exponentiation. This leads to a very fast RSA-like scheme whenever RSA is to be performed at some central site or when pure-RSA encryption (vs. hybrid encryption) is to be performed.An important feature of the new scheme is a practical scheme that isolates the private key from the system, irrespective of the size of the system, the number of sites, or the number of private operations that need be performed.

Cryptanalysis of ‘nonlinear-parity circuits’ proposed at Crypto '90

In Koyama and Terada proposed a family of cryptographic functions for application to symmetric block ciphers. The authors show that this family of circuits is affine over GF(2). More explicitly, for any specific key K, the ciphertext Y is related to the plaintext X by the simple affine relation Y = MKX ⊕ dK where MK is an n × n non singular binary matrix and dK is an n × 1 binary vector where n is the block length of the cipher. This renders this family of ciphers completely insecure as it can be broken with only n + 1 linearly independent plaintext blocks and their corresponding ciphertext blocks.

Comment on “bounds on the number of functions satisfying the strict avalanche criterion”

The Strict Avalanche Criterion (SAC) was introduced by Webster and Tavares (1995) in a study of design criteria for certain cryptographic functions. O'Connor (1994) gave an upper bound for the number of functions satisfying the SAC. Cusick (1996) gave a lower bound for the number of functions satisfying the SAC. He also gave a conjecture that provided an improvement of the lower bound. We give a constructive proof for this conjecture. Moreover, we provide an improved lower bound.

Cryptographic redundancy and mixing functions

This paper studies the use of structures based on error correcting codes to achieve secrecy rather than error control. In many cases, however, the same code can achieve both error control and secrecy. It describes an optimal construction for combining multiple semisecure channels, e.g., a bundle of fiber-optic cables or reels of tape sent by independent couriers, into a single channel with much higher security. It shows how mixing and scrambling functions formed from error correcting codes can be used to enhance the security of trunked communications circuits and conventional cryptographic systems which depend, for their security, on unproven assertions about computational difficulty.

Bounds on the number of functions satisfying the Strict Avalanche Criterion

The Strict Avalanche Criterion (SAC) was introduced by Webster and Tavares in a study of design criteria for certain cryptographic functions.

Characterizing the structures of cryptographic functions satisfying the propagation criterion for almost all vectors

Many practical information authentication techniques are based on such cryptographic means as data encryption algorithms and one-way hash functions. A core component of such algorithms and functions are nonlinear functions. In this paper, we reveal a relationship between nonlinearity and propagation characteristic, two critical indicators of the cryptographic strength of a Boolean function. We also investigate the structures of functions that satisfy the propagation criterion with respect to all but six or less vectors. We show that these functions have close relationships with bent functions, and can be easily constructed from the latter.

The Relationship Between Propagation Characteristics and Nonlinearity of Cryptographic Functions

The Relationship Between Propagation Characteristics and Nonlinearity of Cryptographic Functions

TESS: A security system based on discrete exponentiation

The exponential security system TESS is a toolbox set system of different but cooperating cryptographic mechanisms and functions based on the primitive of discrete exponentiation. With these basic TESS functions, the security system user is able to adapt to very different ranges of applications and security requirements for computer systems, networks, mobile communication, identification, electronic cash, medical or road privacy. This paper describes the basic mechanisms and functions of TESS, demonstrating their suitability to applications in network security and electronic signature. For practitioners, an overview of the implementation of the system is given.

Improving the strict avalanche characteristics of cryptographic functions

This letter presents a simple yet effective method for transforming Boolean functions that do not satisfy the strict avalanche criterion (SAC) into ones that satisfy the criterion. Such a method has a wide range of applications in designing cryptographically strong functions, including substitution boxes (S-boxes) employed by common key block encryption algorithms.

Systematic design of a family of attack-resistant authentication protocols

Most existing designs for two-way cryptographic authentication protocols suffer from one or more limitations. Among other things, they require synchronization of local clocks, they are subject to export restrictions because of the way they use cryptographic functions, and they are not amenable to use in lower layers of network protocols because of the size and complexity of messages they use. Designing suitable cryptographic protocols that cater to large and dynamic network communities but do not suffer from these problems presents substantial problems. It is shown how a few simple protocols, including one proposed by ISO, can easily be broken, and properties that authentication protocols should exhibit are derived. A methodology for systematically building and testing the security of a family of cryptographic two-way authentication protocols that are as simple as possible yet resistant to a wide class of attacks, efficient, easy to implement and use, and amenable to many different networking environments is described. Examples of protocols of that family that presents various advantages in specific distributed system scenarios are discussed. >

Principles of key management

Security services based on cryptographic mechanisms assume keys to be distributed prior to secure communications. The secure management of these keys is one of the most critical elements when integrating cryptographic functions into a system, since any security concept will be ineffective if the key management is weak. This work approaches the problem of key management in a modular and hierarchical manner. It discusses key management security requirements, deals with generic key management concepts and design criteria, describes key management services and building blocks, as well as key management facilities, key management units, and their interrelationship.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

CISS: Generalized security libraries

The paper describes the content, structure, implementation and usage of the Generalized Security Libraries. There are two of these libraries: the library with general mathematical and cryptographic functions with large integers, and the library with various security mechanisms, implemented with modules from the first library. The paper describes the second library. The modules from the library can be used in a flexible way, so that various security services and security systems may be implemented based on usage of the library. All modules are implemented in ANSI.C and comply with existing international (ISO) standards. The library is available for commercial distribution as the CISS-EDU (educational and demo) sytem or incorporated in several larger security products and systems[1].

COSINE Sub-Project P8: security services

COSINE Sub-Project P8, with its limited but attainable goals of secure E-Mail and secure remote access, supported by a Certification Authority and public key cryptographic functions, is intended to demonstrate that these functions can be provided in a relatively short time, and serve a very useful purpose. It is hoped that the project will itself extend to more users and possibly to more services in the future. It is intended to provide practical experience for other more ambitious projects.

The implementation of TSS

The IBM Transaction Security System (TSS, product family 475 x) is an integrated hardware and software implementation of common cryptographic functions. Together with the software support package SECIWS, TSS is designed to improve security at PC workstations, communication channels between workstations and between workstations and host processors. In September 1990, IBM announced a security extension of its System Application Architecture (SAA). One part of this extension is the Common Cryptographic Architecture (CCA). CCA has the objective of standardizing prime cryptographic functions such as: confidentiality, integrity, authenticity, person verification and related key management. All new IBM cryptographic products will support CCA or do so already. This article describes the objectives and implementation of the IBM Transaction Security System with regard to ensuring the security of a stand-alone workstation. The capacity of TSS to safeguard LAN communication as well as between a host and a workstation are beyond the scope of this publication.

Transaction Security System extensions to the Common Cryptographic Architecture

A well-designed application program interface for a line of cryptographic products simplifies customer use of cryptographic services by helping to ensure compliance with national and international standards and by providing intuitive high-level services that may be implemented on disparate systems. The Common Cryptographic Architecture is IBM's strategic cryptographic architecture. The Transaction Security System implements the Common Cryptographic Architecture in full. Furthermore, the Transaction Security System has implemented extensions to the architecture to address additional customer requirements. This paper gives the design rationale for some of the additional cryptographic functionality in the Transaction Security System beyond that mandated by the Common Cryptographic Architecture.