This work is about cryptography in general but also how the Encryption works, and what's needed for Encryption to work. I will also take up a little around the history around the Encryption..

This thesis compares the impact on disk performance in a GNU/Linux  environmentwith three Encryption algorithms: AES,  Serpent and Twofish in three different implementations: DM-crypt, Loop-AES and Truecrypt. For all three algorithms a key length of 256 bits is used.The thesis shows that the least performance impact during data Encryption, and thus file writing, is reached by using AES or Twofish Encryption implemented in DM-crypt or TrueCrypt. The thesis shows that some data operations with a sufficiently low processor utilization barely affects disk performance at all if encrypted using the optimal implementation and algorithm.It is also discovered that the performance impact during data decryption, or file reading, can be minimized by using the most efficient implementation and algorithm. The best results are met with the AES or Twofish cipher, regardless of implementation.An important conclusion that  is  drawn is that it is hard to determine a superior Encryption solution for all purposes. However, by reviewing and examining the collected data from all aspects of disk performance the AES implementation in TrueCrypt is, with small marginals, determined to be the most optimal..

When the use of Encryption amongst the regular computer user grows morewidespread than ever it makes the life of the IT-forensics experts difficult.Hampering the judicial investigations that otherwise could have lead to convictions.In this report we will treat the subject of crypto analysis with a focus on decrypting files and devices encrypted with the software TrueCrypt. A solution will be presented that can facilitate the future work involving Encryption. The application DFEAT that has been developed during the writings of this report is faster than the corresponding software EFDD, and attacks both partitions and bitwise copies of entire harddrives where PKF fails.DFEAT is a lightweight application that is almost 50 times smaller compared to EFDD and 200 times smaller than PKF's portable version..

Communication between parties in an important process in their relationship can be based on a contract. This communication can for exemple be composed by a handwritten contract or an electronic contract. Contract law makes no difference between these two forms. to create more favourable requirements for commencing a contract or an ongoing contract there are possibilities to use standard agreements. Therefore a contract can be based on the will of the parties or on a standard agreement.An electronic signature shall secure that electronic transferred information has not been altered and also to identify the sender of the information.

I detta arbete undersöks hur kryptering påverkar prestandan hos en XML-databas. Detta görs med hjälp av ett inom litteraturen populärt dataset, XMark. Kryptering genomförs med hjälp av standarden XML Encryption. Okrypterade dataset jämförs med krypterade dataset genom att ställa Xpath-frågor och mäta tiden för dessa frågeställningar. Resultaten presenteras i tabeller och grafer och analyseras utifrån ett prestandaperspektiv.

Today the Internet is used more and more as a transportation for information. Much of the information is confidential and should not be read by those not privileged. To protect the information from unauthorized access cryptography can be applied. The cryptography algorithms in use today all have their pros and cons. They are therefore suited for different applications.

Today the Internet is used more and more as a transportation for information. Much of the information is confidential and should not be read by those not privileged. To protect the information from unauthorized access cryptography can be applied. The cryptography algorithms in use today all have their pros and cons. They are therefore suited for different applications.

Den här rapporten beskriver arbetet och utförda studier inom området kryptering och VPN. Fokus ligger på hur väl krypteringsalgoritmerna Triple Data Encryption Standard (3DES) och Advanced Encryption Standard (AES) skalar i en förutbestämd miljö. Huvudfokus har varit att svara på frågan: Vilken av krypteringsalgoritmerna AES och 3DES kräver minst systemresurser? Under utbildningstiden har det flera gånger framförts att 3DES-algoritmen skulle vara mer krävande för krypteringsenheterna att utföra jämfört med AES. Denna rapport söker finna om det är så det förhåller sig och i så fall hur stor skillnaden är mellan algoritmerna.

Information stored on unprotected computers that gets lost or stolen, and falls intothe wrong hands, can easily be accessed by moving the hard disk to a controlledcomputer, or by booting the computer from a removable medium, in order to getaround the operating system login. This is something that largely affects companieswhere customer information, trade secrets and other sensitive information can becompromised. A classic solution to the problem is Encryption of individual files, but ithas some drawbacks as it puts a great responsibility on the users and unencryptedinformation can be left by mistake. A better solution to the problem is transparentEncryption of the entire hard disk, i.e. that Encryption and decryption of informationis performed automatically and without the user being affected.

When a car owner want to lock or unlock his or her car today, it?s preferable done by using aremote control. The system is really comfortable when the car owner is using the remote.A problem arises if a thief gets the remote.The thief doesn?t have to know where the car is parked, an approximate estimation where thecar is parked is enough.For instance, it?s enough to know which car park the car is parked in. If the thief knows that,he/she can repeatedly activate the remote control while looking for a car indicating with lightsand sounds.Because of the fact that a car usually indicates that it has been unlocked by making a shortsound indication, there will be no problem finding the car.The purpose with this project is to make a prototype which makes it harder for a thief to findthe car.

In contemporary Encryption the vast amount of text subject to cracking has brought about the demand for methods distinguish files more likely to be encrypted. The Encryption software Truecrypt can encrypt files that are not possible to identify with a file signature. To solve the detection problem, an algorithm sensitive to the absence of structure in the very code of files was developed. The program was written in the programming language EnScript which is built into the forensic software suite EnCase. The essential part of the algorithm therefore deployes the statistic of a chi-square test for deviance from a uniform distribution to distinguish files with contents that appear to be random.

Saab Bofors Dynamics AB is looking for ways to let the employees work wireless in the future. The security in Wireless Local Area Networks (WLAN) has not been considered very reliable, but new standards and protocols have been developed to enhance the security in WLAN. Since most wireless components soon will have built in support for wireless communication, it is important to have a model to deal with secure wireless communication ready. This is necessary because it is important to protect the company?s information related systems, ensure contingency in the daily work and maintaining the trust of the market and the authorities.

This report is the result of a sub-project of a larger project to create a platform formathematical education. The sub-project focuses on authentication with associ-ated security, where security is emphasized. The project environment is Java EE 6where GlassFish 4.0 acts as the server. The project has been divided into threeparts; password Encryption, Java EE authentication and brute force attack. Thepassword Encryption part focuses on examining different hash functions executionspeed, the result shows that none of the examined hash algorithms is suitable fordirect use.

This master?s thesis investigates the technology and security awareness associated with wireless networks (WLAN). It has been stated by the media and theories that many wireless networks are unprotected. This has sparked an interest to investigate the phenomenon in the Jonkoping region. The study is based on the following research questions:- What security weaknesses are present with the WLAN-technology and how can these be avoided?- How does the wireless infrastructure in the Jonkoping region look like?- Why do companies implement the WLAN-technology?- Are the companies aware of the risks involved with WLAN?We conducted this study in three steps; the first step was to hack a wireless network in a controlled environment in order to investigate the weaknesses of the commonly used security measures.

This paper is a study and comparison between the two Wireless LAN (WLAN) standards HiperLAN/2 and IEEE 802.11a. WLANs are used instead or together with ordinary LANs to increase mobility in for example an office. HiperLAN/2 is an European standard developed by ETSI and the IEEEs standard is American. A WLAN-card consists roughly of a Medium Access Control (MAC), Physichal layer (PHY) and an antenna. The antenna is the same for the different standards.