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 to believe that the message…
Tag: 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 cryptographer Joan Daemen and Vincent…
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 over the entire message, whereas a polyalphabetic cipher uses a number of substitutions at different positions in the…
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 of a message to change…
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 data and data origination can…
Analysis of the Brain Virus, the Internet worm and Code Red
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 the Microsoft Operating System. Numerous…