Randomized Encryption Cryptosystem

Cryptography is the art of secret writing. There are essentially two types of cryptosystems. (i) Secret-key cryptosystems also called symmetric cryptosystems (ii) Public-key cryptosystems also called asymmetric cryptosystems. In this paper, we shall consider a Public-key cryptosystem whose security is based on the infeasibility of the Quadratic Residuosity Problem (QRP

Critical analyses of some public-key cryptosystems for high-speed satellite transmission applications

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.Vita.Bibliography: leaves 83-86.by Moses Hsingwen Ma.M.S

p-adic number theory and its applications in a cryptographic form

Imperial Users onl

Ataques ao sistema criptográfico RSA

Mestrado em Matemática e AplicaçõesO RSA é um sistema criptográfico de chave pública, inventado, em 1978, por Rivest, Shamir e Adleman. Neste trabalho, serão abordadas várias técnicas desenvolvidas desde então para quebrar este sistema. Iremos descrever vários métodos de factorização, de onde destacamos o crivo quadrático, o crivo geral dos corpos de números e o método das curvas elípticas. Iremos também estudar vários ataques ao RSA que, de forma a serem evitados, vieram a permitir uma implementação mais adequada do RSA. Destes ataques destacamos aqueles que quebram o RSA quando o expoente público ou o expoente privado são demasiado pequenos, o ataque dos tempos de Kocher e o ataque com parte da chave privada exposta. Muitos dos métodos descritos são acompanhados, em apêndice, com um algoritmo, construído no software Maple 9.5.The RSA is a cryptographic system invented in 1978 by Rivest, Shamir and Adleman. In this work, we will study several methods developed since then to break this system. We will describe some factorization methods, of which we highlight the quadratic sieve, the general number field sieve and the elliptic curve method. We will also study several attacks to RSA that, in order to avoid them, a better implementation of the RSA was achieved. In particular, we will describe those that break the RSA when a small public exponent or a small private exponent is used. We will also see the Kocher’s timing attack and partial private key exposure attack. Many of the methods are accompanied, in the appendix, by an algorithm constructed using the software Maple 9.5

The Cultural Contradictions of Cryptography

This dissertation examines the origins of political and scientific commitments that currently frame cryptography, the study of secret codes, arguing that these commitments took shape over the course of the twentieth century. Looking back to the nineteenth century, cryptography was rarely practiced systematically, let alone scientifically, nor was it the contentious political subject it has become in the digital age. Beginning with the rise of computational cryptography in the first half of the twentieth century, this history identifies a quarter-century gap beginning in the late 1940s, when cryptography research was classified and tightly controlled in the US. Observing the reemergence of open research in cryptography in the early 1970s, a course of events that was directly opposed by many members of the US intelligence community, a wave of political scandals unrelated to cryptography during the Nixon years also made the secrecy surrounding cryptography appear untenable, weakening the official capacity to enforce this classification. Today, the subject of cryptography remains highly political and adversarial, with many proponents gripped by the conviction that widespread access to strong cryptography is necessary for a free society in the digital age, while opponents contend that strong cryptography in fact presents a danger to society and the rule of law. I argue that cryptography would not have become invested with these deep political commitments if it had not been suppressed in research and the media during the postwar years. The greater the force exerted to dissuade writers and scientists from studying cryptography, the more the subject became wrapped in an aura of civil disobedience and public need. These positive political investments in cryptography have since become widely accepted among many civil libertarians, transparency activists, journalists, and computer scientists who treat cryptography as an essential instrument for maintaining a free and open society in the digital age. Likewise, even as opponents of widespread access to strong cryptography have conceded considerable ground in recent decades, their opposition is grounded in many of the same principles that defined their stance during cryptography’s public reemergence in the 1970s. Studying this critical historical moment reveals not only the origins of cryptography’s current politics, but also the political origins of modern cryptography