A digital signature is a digital code (generated and authenticated by public key encryption) which is attached to an electronically transmitted document to verify its contents and the sender’s identity. A digital signature is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason […]

# Category: Information Security

## AES encryption

AES encryption web tool to encrypt and decrypt text using AES encryption algorithm. You can chose 128, 192 or 256-bit long key size for encryption and decryption. The result of the process is downloadable in a text file. AES (acronym of Advanced Encryption Standard) is a symmetric encryption algorithm. The algorithm was developed by two Belgian […]

This post discusses the difference between substitution and transposition in terms of encryption. There are a number of different types of substitution cipher. If the cipher operates on single letters, it is termed a simple substitution cipher; a cipher that operates on larger groups of letters is termed polygraphic. A monoalphabetic cipher uses fixed substitution […]

## Asymmetric Encryption

There are two basic techniques for encrypting information: symmetric encryption (also called secret key encryption) and asymmetric encryption (also called public-key encryption.) Symmetric Encryption Symmetric encryption is the oldest and best-known technique. A secret key, which can be a number, a word, or just a string of random letters, is applied to the text […]

## The goal of non-repudiation

Nonrepudiation is a method of guaranteeing message transmission between parties via digital signature and/or encryption. It is one of the five pillars of information assurance (IA). The other four are availability, integrity, confidentiality and authentication. Nonrepudiation is often used for digital contracts, signatures and email messages. By using a data hash, proof of authentic identifying […]

These are the four primary threats to security in computing: Interception – Unauthorized party (person, program, or computing system) gains access to an asset – E.g. illicit copying of program or data files, wiretapping to obtain data in a network Interruption – Asset becomes lost, unavailable, or unusable- E.g. malicious destruction of h/w device, erasure […]

The Brain Virus How it works: One of the earliest and most intensively studied viruses, the so-called Brain Virus got its name by the means of its attack, in which it changes the label of any infected disk to the word “BRAIN”. Believed to have originated in Pakistan, it attacks PCs with older versions of […]