In this paper, a hash function with lower rate but higher efficiency is proposed and it can be built on insecure compression functions. The security of this scheme is proved under black-box model and some compression function based on block ciphers are given to build this scheme. It is also shown that key schedule is a more important factor affecting the efficiency of a block-cipher-based hash function than rate. The new scheme only needs 2 keys and the key schedule of it can be pre-computed. It means the new scheme need not re-schedule the keys at every step during the iterations and its efficiency is improved.

Hash Functions Based on Block Ciphers

This paper deals with a modification of the Hill cipher. In this, we have introduced interweaving in each step of the iteration. The interweaving of the resulting plaintext, at each stage of the iteration, and the multiplication with the key matrix leads to confusion and diffusion. From the cryptanalysis performed in this investigation, we have found that the cipher is a strong one.

/pdf/a-modified-hill-cipher-involving-interweaving-and-iteration-zec38qjwy5.pdf

A Modified Hill Cipher Involving Interweaving and Iteration

/pdf/a-modified-version-of-playfair-cipher-using-7-4-matrix-19804v7q84.pdf

A Modified Version of Playfair Cipher Using 7×4 Matrix

Cryptography plays an important role in today’s digital world. For the purpose of security and privacy, we need to encrypt the message at the sender side and decrypt it at the receiver side. This paper deals with the modification of playfair cipher. The original 5x5 matrix playfair cipher is modified to mxn matrix playfair cipher in which two symbols”*” and “#” are included. The addition of these two symbols in the matrix creates one-to-one correspondence between the plain text and the Cipher text, which makes the encryption and decryption easy and unambiguous. The text becomes more secure when these symbols appear in the resulting Cipher text. The proposed method can be used to encrypt and decrypt the messages of any natural language by taking a proper size matrix. For some european languages if the decrypted message contain characters superscripts or subscripts with special symbols (e.g.a,c), it will be read by the machine in the same accent as by the human being.

Universal Playfair Cipher Using MXN Matrix

The design principles proposed independently by both Ralph Merkle and Ivan Damgard in 1989 are applied widely in hash functions that are used in practice. The construction reads the message in one message block at a time and applies iteratively a compression function that, given a single message block and a hash value, outputs a new hash value. This iterative structure has some security weaknesses. It is vulnerable, for instance, to Joux's multicollision attack, herding attack that uses diamond structures and Trojan message attack. Our principal research topic comprises the deficiencies in hash function security induced by the Merkle-Damgard construction. In this work, we present a variant of Joux's multicollision attack. We also develop a new, time-saving algorithm for creating diamond structures. Moreover, two new efficient versions of Trojan message attack are introduced. The main contribution of the thesis is the analysis of generalized iterated hash functions. We study the combinatorial properties of words from a new perspective and develop results that are applied to give a new upper bound for the complexity of multicollision attacks against the so called q-bounded generalized iterated hash functions.

/pdf/on-iteration-based-security-flaws-in-modern-hash-functions-2oti5bpe4k.pdf

On iteration-based security flaws in modern hash functions

Recently Nandi etc. have proposed a 1/3-rate and a 2/3-rate double length compression functions and studied their security in the black-box model. They proved that to find a collision for the compression function, it requires (2 2n/3 ) queries, where n is the length of output size. In this paper, we show that not all hash functions based on block cipher constructed according to their model are of the same security .i.e., the complexity to find the collisions for these hash functions can be reduced to O(2 n/2 ).

/pdf/security-analysis-of-double-length-compression-function-2ip2wz9ctb.pdf

Security Analysis of Double Length Compression Function Based on Block Cipher

At CRYPTO 2005, Coron etc. proposed several modified methods to make the usual hash functions based on MD method indifferentiable from random oracles. However, the compression functions used in Coron's schemes are supposed to be random oracles. This assumption is too strong. To achieve Coron's goal in the real world, Liskov proposed Zipper structure and implemented a new scheme indifferentiable from random oracle based on this structure. Unlike Coron's schemes, the indifferentiability of Liskov's scheme does not depend on strong compression functions and insecure compression functions can be used to implement Liskov's scheme. In this paper, we show that the security of Liskov's scheme is not ideal as a hash function. We also analyze those Zipper schemes whose compression functions are insecure PGV compression functions instead of Liskov's weak compression functions, and we find that some insecure PGV compression functions whose security is stronger than Liskov's weak compression function cannot be used to build indifferentiable and collision-resistant Zipper schemes.

Analysis of Zipper as a hash function

The most popular method to construct hash functions is to iterate a compression function on the input message. This method is called Merkle-Damgard method. Most hash functions used in practice such as MD4, MD5, SHA-0, SHA-1 are based on this method. However this method is not always the best. For example, this method can not resist multi-collision attack. Recently some modifications of this method are proposed. These modified methods are based on Merkle-Damgard method and some improvements are made. A hash function based on All-or-Nothing property is one of these improve-ments. All-or-nothing property is an encryption mode for block ciphers. It has the prop-erty that one must decrypt all cipher blocks to determine any plain-text block. All-or- nothing hash function is a kind of hash function constructed with the all-or-nothing property. The authors of it claim that it is more secure than those common hash functions. In this paper, we will show that this is not true and there are still some flaws on this im-proved method.

Analysis of All-or-Nothing Hash Functions *

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Pin Lin

Author Tools

Chat about Author

Papers

Security Analysis of Double Length Compression Function Based on Block Cipher

Analysis of Zipper as a hash function

Analysis of All-or-Nothing Hash Functions *