Many network operators need to be able to ensure that customers get the level of service they pay for. To avoid bandwidth and server performance bottlenecks, and easily troubleshoot network problems, the network providers need to be able to see what payload data is sent. Modern networks encrypt data when sending it between nodes that makes passive monitoring more complex. A prevalent encryption mechanism on an IP-based network is TLS that needs to be decrypted.                This article’s purpose is to check if it is possible to decrypt TLS traffic in a passive monitoring system with the server’s private key. This is done by implementing a decryptor in a passive monitoring system in the programming language Java. The implemented solution intercepts the traffic, takes out relevant data from the traffic, and derives the session key from that data. How this is done is dependent on what cipher suite is used for the session. Because of delimitations and lack of time the solution is only able to decrypt the cipher suite TLS_RSA_WITH_AES_128_CBC_SHA256. The result showed that it is possible to decrypt TLS traffic and should be possible for more than the specified cipher suite. But there exists a major problem that's called forward secrecy. This is used in the key exchange algorithm called Diffie–Hellman and makes it impossible to decrypt with only server private key. The conclusion is that it is possible but because of forward secrecy, it is not recommended. TLS 1.3 only uses cipher suites with the key exchange algorithm Diffie–Hellman and the forward secrecy functionality is important for security.

This thesis deals with encryption of short text message (SMS) in mobile communication. Introduction is dedicated to overview of the parts of GSM radiotelephone nets and SMS messages transfer . Next chapter is reserved for description of cryptographic methods especially symetric and asymetric encryptografic aproaches. A design of a SMS messages encryption and decryption techniques is in next. For SMS encryption and sign, there is used the asymetric cypher RSA. Encryption use OAEP padding schema. The public key is saved in certificate. The Symbian OS has been choosen as a suitable platform for programming of mobile devices.

In today's interconnected digital landscape, the protection of sensitive information is of great importance. As a result, the field of cryptography plays a vital role in ensuring individuals' anonymity and data integrity. In this context, this thesis presents a comprehensive analysis of symmetric encryption algorithms, specifically focusing on the Advanced Encryption Standard (AES) and Camellia. By investigating the performance aspects of these algorithms, including encryption time, decryption time, and ciphertext size, the goal is to provide valuable insights for selecting suitable cryptographic solutions. The findings indicate that while there is a difference in performance between the algorithms, the disparity is not substantial in practical terms. Both AES and Camellia, as well as their larger key-size alternatives, demonstrated comparable performance, with AES128 showing marginally faster encryption time. The study's implementation also involves encrypting a data set with sensitive information on students. It encrypts the school classes with separate keys and assigns roles to users, enabling access control based on user roles. The implemented solution successfully addressed the problem of role-based access control and encryption of unique identifiers, as verified through the verification and validation method. The implications of this study extend to industries and society, where cryptography plays a vital role in protecting individuals' anonymity and data integrity. The results presented in this paper can serve as a valuable reference for selecting suitable cryptographic algorithms for various systems and applications, particularly for anonymization of usernames or short, unique identifiers. However, it is important to note that the experiment primarily focused on small data sets, and further investigations may yield different results for larger data sets.

No description available.

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.

The increasing availability of easy-to-use end-to-end encrypted messaging applications has made it possible for more people to conduct their conversations privately. This is something that criminals have taken advantage of and it has proven to make digital forensic investigations more difficult as methods of decrypting the data are needed. In this thesis, data from iOS and Windows devices is extracted and analysed, with focus on the application Signal. Even though other operating systems are compatible with the Signal application, such as Android, it is outside the scope of this thesis. The results of this thesis provide access to data stored in the encrypted application Signalwithout the need for expensive analysis tools. This is done by developing and publishing the first open-source script for decryption and parsing of the Signal database. The script is available for anyone at https://github.com/decryptSignal/decryptSignal.

No description available.

Security is very important in present day life. In this highly-interconnected world, most of our daily activities are computer based, and the data transactions are protected by passwords. These passwords identify various entities such as bank accounts, mobile phones, etc. People might reuse the same password, or passwords related to an individual that can lead to attacks. Indeed, remembering several passwords can become a tedious task. Biometrics is a science that measures an individual’s physical characteristics in a unique way. Thus, biometrics serves as a method to replace the cumbersome use of complex passwords. Our research uses the features of biometrics to efficiently implement a biometric encryption system with a high level of security.

High data rates and interoperability of vender devices have made WiMAX a prime desire for use worldwide. WiMAX is based on the IEEE 802.16 standard. IEEE 802.16a, b, c & d versions were updated within three years of the first launch of WiMAX. However, during those early years reports were published that highlighted the security weaknesses of the standard. These weaknesses prompted the IEEE to issue a new version, 802.16e to tackle the security issues. Despite this security enhancement, WiMAX remains vulnerable. This research project looks at the vulnerability of WiMAX 802.16e Subscriber Station/Mobile Station authentication at the initial entry and proposes approaches to the prevention of Denial of Service (DoS) attacks at this point in order to secure the Media Access Control (MAC) layer from such threats. A new protocol has been designed and developed to provide confidentiality, authentication and integrity to WiMAX users. This new protocol is integrated with Z algorithm (an algorithm described later in this paper) to provide: • Confidentiality of management messages • Message Authentication code • ID to provide for message integrity and user authentication. A simulation package was also required, to prove that a linear load of DoS attack would disable or exhaust the capacity of the base station of a WiMAX network, as well as providing other simulation functions. The freely available simulation tool NIST (NIST IPSec (Internet Protocol Security) and IKE (Internet Key Exchange) Simulation) is oriented towards fixed network communications (NIIST, 2003). There are no other relevant simulation tools; hence the purpose of this research project is to develop a new tool to simulate WiMAX security vulnerabilities and test the new protocol.

The aim of this dissertation is to improve computational efficiency of modular exponentiation-based public-key cryptosystems. The operational speed of these public-key cryptosystems is largely determined by the modular exponentiation operation of the form A = ge mod m where g is the base, e is the exponent and m is the modulus. The required modular exponentiation is computed by a series of modular multiplications. Optimized algorithms are required for various platforms, especially for lower-end platforms. These require the algorithms to be efficient and consume as little resources as possible. In these dissertation algorithms for integer multiplication, modular reduction and modular exponentiation, was developed and implemented in software, as required for public-key cryptography. A detailed analysis of these algorithms is given, as well as exact measurement of the computational speed achieved by each algorithm. This research shows that a total speed improvement of 13% can be achieved on existing modular exponentiation based public-key cryptosystems, in particular for the RSA cryptosystem. Three novel approaches are also presented for improving the decryption speed efficiency of the RSA algorithm. These methods focus on the selection of the decryption exponent by careful consideration of the difference between the two primes p and q. The resulting reduction of the decryption exponent improves the decryption speed by approximately 45%. / Dissertation (MEng (Electronics))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted