60 research outputs found

    Vulnerability-Tolerant Transport Layer Security

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    SSL/TLS communication channels play a very important role in Internet security, including cloud computing and server infrastructures. There are often concerns about the strength of the encryption mechanisms used in TLS channels. Vulnerabilities can lead to some of the cipher suites once thought to be secure to become insecure and no longer recommended for use or in urgent need of a software update. However, the deprecation/update process is very slow and weeks or months can go by before most web servers and clients are protected, and some servers and clients may never be updated. In the meantime, the communications are at risk of being intercepted and tampered by attackers. In this paper we propose an alternative to TLS to mitigate the problem of secure commu- nication channels being susceptible to attacks due to unexpected vulnerabilities in its mechan- isms. Our solution, called Vulnerability-Tolerant Transport Layer Security (vtTLS), is based on diversity and redundancy of cryptographic mechanisms and certificates to ensure a secure communication even when one or more mechanisms are vulnerable. Our solution relies on a combination of k cipher suites which ensure that even if k ? 1 cipher suites are insecure or vul- nerable, the remaining cipher suite keeps the communication channel secure. The performance and cost of vtTLS were evaluated and compared with OpenSSL, one of the most widely used implementations of TLS

    An Overview of Cryptography (Updated Version, 3 March 2016)

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    There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communications is that of cryptography...While cryptography is necessary for secure communications, it is not by itself sufficient. This paper describes the first of many steps necessary for better security in any number of situations. A much shorter, edited version of this paper appears in the 1999 edition of Handbook on Local Area Networks published by Auerbach in September 1998

    Towards a Secure Smart Grid Storage Communications Gateway

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    This research in progress paper describes the role of cyber security measures undertaken in an ICT system for integrating electric storage technologies into the grid. To do so, it defines security requirements for a communications gateway and gives detailed information and hands-on configuration advice on node and communication line security, data storage, coping with backend M2M communications protocols and examines privacy issues. The presented research paves the road for developing secure smart energy communications devices that allow enhancing energy efficiency. The described measures are implemented in an actual gateway device within the HORIZON 2020 project STORY, which aims at developing new ways to use storage and demonstrating these on six different demonstration sites.Comment: 6 pages, 2 figure

    A Cryptographic Tour of the IPsec Standards

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    In this article, we provide an overview of cryptography and cryptographic key management as they are specified in IPsec, a popular suite of standards for providing communications security and network access control for Internet communications. We focus on the latest generation of the IPsec standards, recently published as Request for Comments 4301ā€“4309 by the Internet Engineering Task Force, and how they have evolved from earlier versions of the standards

    Practical Encryption Gateways to Integrate Legacy Industrial Machinery

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    Future industrial networks will consist of a mixture of old and new components, due to the very long life-cycles of industrial machines on the one hand and the need to change in the face of trends like Industry 4.0 or the industrial Internet of things on the other. These networks will be very heterogeneous and will serve legacy as well as new use cases in parallel. This will result in an increased demand for network security and precisely within this domain, this thesis tries to answer one specific question: how to make it possible for legacy industrial machines to run securely in those future heterogeneous industrial networks. The need for such a solution arises from the fact, that legacy machines are very outdated and hence vulnerable systems, when assessing them from an IT security standpoint. For various reasons, they cannot be easily replaced or upgraded and with the opening up of industrial networks to the Internet, they become prime attack targets. The only way to provide security for them, is by protecting their network traffic. The concept of encryption gateways forms the basis of our solution. These are special network devices, that are put between the legacy machine and the network. The gateways encrypt data traffic from the machine before it is put on the network and decrypt traffic coming from the network accordingly. This results in a separation of the machine from the network by virtue of only decrypting and passing through traffic from other authenticated gateways. In effect, they protect communication data in transit and shield the legacy machines from potential attackers within the rest of the network, while at the same time retaining their functionality. Additionally, through the specific placement of gateways inside the network, fine-grained security policies become possible. This approach can reduce the attack surface of the industrial network as a whole considerably. As a concept, this idea is straight forward and not new. Yet, the devil is in the details and no solution specifically tailored to the needs of the industrial environment and its legacy components existed prior to this work. Therefore, we present in this thesis concrete building blocks in the direction of a generally applicable encryption gateway solution that allows to securely integrate legacy industrial machinery and respects industrial requirements. This not only entails works in the direction of network security, but also includes works in the direction of guaranteeing the availability of the communication links that are protected by the gateways, works to simplify the usability of the gateways as well as the management of industrial data flows by the gateways

    Sigurnosni protokoli

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    The Internet, as a computer network, connects millions of people all around the world and gives them a possibility to access a big quantity of data. Throughout the Internet users exchange data using certain protocols and a part of this communication is private or secret. TCP (Transmission Control Protocol) and IP (Internet Protocol) protocols are the kernel of Internet protocol. Everything that is transmitted through the Internet uses these protocols, but they cannot provide security of data transfer. For example, IP packages can be easily changed and their content can be seen by everybody in every moment, even by an unauthorized person. Today the world is already globally connected and the individuals and institutions need privacy and also the protection from identity theft that is today a very frequent aspect of misuse of the Internet. So, we need transparent and flexible tools to fulfill demands of different users and at the same time capable to achieve the assigned degree of security. Security protocols, as the most prominent SSL (Secure Sockets Layers) and TLS (Transport Layer Security), solve a good part of given problems.Internet, kao računarska mreža, povezuje milione ljudi Å”irom sveta i obezbeđuje im pristup velikoj količini informacija. Korisnici preko Interneta razmenjuju podatke na osnovu određenih protokola, a deo te komunikacije je privatnog ili službeno tajnog karaktera. Pri ovoj razmeni, korisnici resursa računarskih sistema, računara u mrežama i samostalnih računara, pre svega žele da budu sigurni da će pristup njihovim podacima i resursima uopÅ”te imati samo oni kojima se pristup dozvoli. Dakle, analogno sigurnosti fizičke imovine korisnici računarskih sistema žele takozvanu računarsku sigurnost. Jezgro Internet protokola predstavljaju TCP (Transmission Control Protocol) i IP (Internet Protocoll) protokoli. Sve Å”to putuje Internetom koristi ove protokole, ali oni ne obezbeđuje sigurnost prenosa podataka. IP paketi se, na primer, mogu lako izmeniti a njihov sadržaj može u bilo kom trenutku da pregleda ma ko, pa i neovlaŔćena osoba. U svetu koji je danas već globalno povezan, pojedinci i razne institucije imaju potrebe za privatnoŔću, kao i za zaÅ”titom od krađe identiteta, koja postaje sve čeŔći vid zloupotrebe globalne mreže. Dakle, potrebna su sredstva koja su transparentna i dovoljno fleksibilna da zadovolje zahteve raznih korisnika, a istovremeno ostvare zadati stepen sigurnosti. U ovom radu, pažnja je usmerena na komunikacijske zaÅ”titne mehanizme definisane sigurnosnim protokolima, pri čemu se smatra da su ispunjene ostale kategorije računarske sigurnosti. Protokoli TLS (Transport Layer Security) i SSL (Secure Sockets Layers) su kriptografski protokoli koji omogućavaju sigurnu komunikaciju na Internetu za poslove elektronskog bankarstva i trgovine, e-mail, fax, pristup udaljenim računarima, a korisnicima reÅ”avaju dobar deo navedenih problema

    SECURITY AND PRIVACY ISSUES IN MOBILE NETWORKS, DIFFICULTIES AND SOLUTIONS

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    Mobile communication is playing a vital role in the daily life for the last two decades; in turn its fields gained the research attention, which led to the introduction of new technologies, services and applications. These new added facilities aimed to ease the connectivity and reachability; on the other hand, many security and privacy concerns were not taken into consideration. This opened the door for the malicious activities to threaten the deployed systems and caused vulnerabilities for users, translated in the loss of valuable data and major privacy invasions. Recently, many attempts have been carried out to handle these concerns, such as improving systemsā€™ security and implementing different privacy enhancing mechanisms. This research addresses these problems and provides a mean to preserve privacy in particular. In this research, a detailed description and analysis of the current security and privacy situation in the deployed systems is given. As a result, the existing shortages within these systems are pointed out, to be mitigated in development. Finally a privacy preserving prototype model is proposed. This research has been conducted as an extensive literature review about the most relevant references and researches in the field, using the descriptive and evaluative research methodologies. The main security models, parameters, modules and protocols are presented, also a detailed description of privacy and its related arguments, dimensions and factors is given. The findings include that mobile networksā€™ security along with users are vulnerable due to the weaknesses of the key exchange procedures, the difficulties that face possession, repudiation, standardization, compatibility drawbacks and lack of configurability. It also includes the need to implement new mechanisms to protect security and preserve privacy, which include public key cryptography, HIP servers, IPSec, TLS, NAT and DTLS-SRTP. Last but not least, it shows that privacy is not absolute and it has many conflicts, also privacy requires sophisticated systems, which increase the load and cost of the system.fi=OpinnƤytetyƶ kokotekstinƤ PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=LƤrdomsprov tillgƤngligt som fulltext i PDF-format

    On the Practical (In-)Security of 64-bit Block Ciphers: Collision Attacks on HTTP over TLS and OpenVPN

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    While modern block ciphers, such as AES, have a block size of at least 128 bits, there are many 64-bit block ciphers, such as 3DES and Blowfish, that are still widely supported in Internet security protocols such as TLS, SSH, and IPsec. When used in CBC mode, these ciphers are known to be susceptible to collision attacks when they are used to encrypt around 2322^{32} blocks of data (the so-called birthday bound). This threat has traditionally been dismissed as impractical since it requires some prior knowledge of the plaintext and even then, it only leaks a few secret bits per gigabyte. Indeed, practical collision attacks have never been demonstrated against any mainstream security protocol, leading to the continued use of 64-bit ciphers on the Internet. In this work, we demonstrate two concrete attacks that exploit collisions on short block ciphers. First, we present an attack on the use of 3DES in HTTPS that can be used to recover a secret session cookie. Second, we show how a similar attack on Blowfish can be used to recover HTTP BasicAuth credentials sent over OpenVPN connections. In our proof-of-concept demos, the attacker needs to capture about 785GB of data, which takes between 19-38 hours in our setting. This complexity is comparable to the recent RC4 attacks on TLS: the only fully implemented attack takes 75 hours. We evaluate the impact of our attacks by measuring the use of 64-bit block ciphers in real-world protocols. We discuss mitigations, such as disabling all 64-bit block ciphers, and report on the response of various software vendors to our responsible disclosure of these attacks
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