Covert timing channels caching and cryptography software

We implement the proposed method in a software tool based on llvm, targeting cryptographic. In the software world, sidechannel attacks have sometimes been dismissed as. Timing channels can be used to exfiltrate information from a compromised machine. Some examples of covert timing channels are the systems paging rate, the time a certain transaction requires to execute, and the time it takes to gain access to a shared bus. Covert timing channels, caching, and cryptography billy bob brumley. A case study on covert channel establishment via software. Shadowsocks for windows is a free and open source, highperformance secured socks5 proxy designed to protect your internet traffic. Microarchitectural timing channels expose hidden hardware state though timing. With the exception of timing channels, most channels require some physical proximity and sensors to detect the transmitted information, e. Covert timing channels, caching, and cryptography billy bob brumley doctoral dissertation for the degree of doctor of science in technology to be presented with due permission of the school of science for public examination and debate in auditorium as1 at the aalto university school of science espoo, finland on the 16 th of december 2011 at 12 noon. This might use a technique like a dead drop, where i post a picture on ebay, you view the posting on ebay.

Why raspberry pi isnt vulnerable to spectre or meltdown. Phishing knowledge based user modelling in software design. Doctoral dissertation for the degree of doctor of science in technology to be presented with due permission of the school of science for public examination and debate in auditorium as1 at the aalto university school of science espoo, finland on the 16 th of december 2011 at 12 noon. Results on linear models in cryptography, aalto university school of science, 20 hadi soleimany. We describe, implement and quantify a new covert channel through shared hardware.

Billy bob brumley, manuel barbosa, dan page, and frederik vercauteren. Timing channels in cryptography a microarchitectural. Using a particular combination of techniques and exploiting a vulnerability found in the implementation of the dsa signature scheme in the openssl shared library, a cachetiming attack is performed against the dsas. Covert channels involve two or more processes collaborating to communicate. Covert timing channels, caching, and cryptography billy bob brumley doctoral dissertation for the degree of doctor of science in technology to be presented with due permission of the school of science for public examination and debate in auditorium as1 at the aalto university school of science espoo, finland on the 16th of. A covert channel is an intentional communications path that is hidden, using a technique like steganography. Covert timing dd channels, caching, and cryptography. Combination of survey and original research natural places to be concerned about leakage highlevel notes about natural countermeasures. Denis kolegov, an associate professor in the information security and cryptography department at tomsk state university nikita oleksov, a thirdyear student of tomsk state university more. Eliminating timing sidechannel leaks using program repair, 4. This type of cryptography is most commonly used to protect the transmission of software and large files where the publisher of the files or software offers them for download. We can do this by using the pseudo random number generator built into java.

Exploiting p2p applications to trace and profile tor users. A solution besides a would need to step outside the bounds of traditional cryptography. However, tor does not protect against the exploitation of an insecure application to reveal the ip address of, or trace, a tcp stream. In orr dunkelman, editor, topics in cryptology ctrsa 2012 the cryptographers track at the rsa conference 2012, san francisco, ca, usa, february 27 march 2, 2012. In gianvecchio and wang 2011, a covert timing channel has a score less than a threshold in the en, or a score that is either lower or higher than thresholds in the cce. Newest covertchannel questions information security.

In this case study, we investigate the possibility of covert channel establishment via software caches in the context of a framework for componentbased operating systems. Cryptography has been around for thousands of years. They also know in second quote just how bad the problem is with later work finding covert channels in all of that. The reason for this is that, while it is easy to calculate the hash, it is extremely difficult to find an initial input that will provide an exact match for the desired value. Hardwaresoftware integrated approaches to defend against software cachebased side channel attacks. Detecting covert timing channels with timedeterministic.

Timing and sidechannel countermeasures for quantumsafe. Identifying tor users through insecure applications. Covert timing channels, caching, and cryptography, aalto university school of science, 2011 risto matti hakala. This means that its existence is intentional, and additionally there is an intention to conceal or hide its existence from a person who is trying to protect the system by filtering or limiting data flow. Is it possible to make timelocked encrytion algorithm. Every logical operation in a computer takes time to execute, and the time can differ based on the input. Timing information, power consumption, electromagnetic leaks or even sound can provide an extra source of information, which can be. Eliminating timing sidechannel leaks using program repair arxiv. Encryption software is software that uses cryptography to prevent unauthorized access to digital information. The works on network timing channels can be traced back to the workby venkatramanet al. The paper discusses several potential applications of tdr, and studies one of them in detail.

It describes and analyzes various unintended covert timing channels that are formed when ciphers are executed in microprocessors. In some instances, knowing when data is transmitted between parties can provide a malicious user with privileged information. Anyone can see that steve connected to stack exchange. Since it only compares up to the shorter of the two strings, we can start with a string of length 1, then 2, then 3, and so on until the. This book deals with timing attacks on cryptographic ciphers. In computer security, what are covert and side channels. Cryptography software tools welcome to the gmu ece. The original is still open to a little bit of a timing attack although we cant easily determine the contents of the correct string based on timing, we can at least find the string length based on timing. Cryptography is used to protect digital information on computers as well as the digital information that is sent to other computers over the internet. Newish processors with hardware support for aes are much faster than older processors without it aesni in x86 processors and an optimized implementation might be quite different from a generic one, especially if the latter doesnt even use the hardware. Among all wellknown side channels, cache based timing channels are notoriously severe, leading to practical attacks against certain implementations of theoretically secure crypto algorithms, such as rsa, elgamal and aes. Covert channels are frequently classified as either storage or timing channels. There are many software products which provide encryption.

Covert channels and countermeasures in computer network. In this work, we propose a novel technique to help software. Covert channel algorithms is most commonly used as a name given to a set of algorithms used in idsips intrusion detectionprevention systems to detect, analyze and identify covert channels in tcpip networks, for example by probabilistic statistical analysis by e. More generally, cryptography is about constructing and analyzing protocols that prevent. Practical realisation and elimination of an eccrelated software bug attack. Eliminating timing sidechannel leaks using program repair. The first thing to do is to generate a random secret key to use. Ciphers allow alice and bob to scramble and descramble their messages so that they would appear meaningless if eve intercepted them. Next installment in the cryptography lesson series the major difficulty will be decoding the cache location.

Cryptography, rsa, side channels, simultaneous multithreading, caching. Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information. The private key was retrieved out of the windowsmy keystore and the public key from a users certificate. Covert channels can be utilized to secretly deliver information from high privileged processes to low privileged processes in the context of a highassurance computing system. This work explains some of the cachetiming techniques commonly used to exploit vulnerable software.

Pdf a case study on covert channel establishment via software. Among all wellknown side channels, cachebased timing channels are notoriously. An overt channel is a communications path that is not hidden. When it comes to cryptographic software, side channels. Wray made a srm replacement for timing channels year before. A survey of timing channels and countermeasures acm. Studies in lightweight cryptography, aalto university school of science, 2015 mikko kiviharju. It describes and analyzes various unintended covert timing channels that are formed. In timing channels, the time variable is controlled. Due to the difficulty of extracting the trace of cache hits and misses in software. Later work finds that timing information reveals the victim programs usage of datainstruction cache, leading to efficient timing attacks against real world cryptography software, including aes. Covert channels and countermeasures in computer network protocols. Its a not chosen size geocache, with difficulty of 5, terrain of 3.

This technique attempts to bypass network security protections like firewalls and ids. Cryptography software tools main features rsa encryption search public keys for the receiver by id by last name by first name load message want to send by typing in message boxby typing in message box by load from text file encrypt message intermediate values show in iterative box option to save all calculation to text file. Meanwhile, many timingbased covert channels are very powerful as they do not require physical access, only that sender and receiver run some code on the same system. The speed depends a lot on the exact model of the processor, and on the software. Modern superscalar microprocessors are considered, which are enabled with features such as multithreaded, pipelined, parallel, speculative, and outoforder execution. Covert channels are a stealthy medium of data transfer using common network protocols.

The mitigation mechanisms towards cachebased timing channels can be categorized into hardware and software based solutions. In computer security, a sidechannel attack is any attack based on information gained from the implementation of a computer system, rather than weaknesses in the implemented algorithm itself e. But you cant just hand someone bits that are undecryptable before some arbitrary time. Cryptography begins when we abandon physical locks and use ciphers instead. Further hardware and software countermeasures are discussed with the aim of illustrating. Storage channels consist of variables that are set by a system process on behalf of the sender, e. Topics range from the history of cryptography, to highlevel concepts like ciphers and key exchange. Advanced timedriven cache attacks on block ciphers. These episodes are designed to demystify the world of cryptography. We can do this easily with the java cryptography functions. Identifying cache based timing channels in production software, booktitle 26th usenix security symposium usenix.

In cryptography, a timing attack is a sidechannel attack in which the attacker attempts to compromise a cryptosystem by analyzing the time taken to execute cryptographic algorithms. The library features the most widely used symmetric and asymmetric cryptography algorithms that are offered in a number of configuration options to meet specific application requirements. Covert channels present serious security threat because they allow secret communication between two malicious processes even if the system inhibits direct communication. This paper discusses several of the obstacles in detail. Instructor even using private files, we may want to have the additional protection offered by cryptography to protect our data. Some network timing channels require time synchronizationbetween encoder and decoder. In crypto, algorithm public, key secret but known channels are closeable should the channel be secret too. Hardwarebased solutions focus on new cache designs such as partitioned cache 43,54, 31,61, randomizedremapping cache 54,55,33, and.

For example, you would need a dedicated platform software or hardware that you can assume is unbreakable that will only perform a decryption operation at a certain time. Cryptography software has become much more common since the emergence of the internet. A survey of microarchitectural timing attacks and countermeasures. Discover practical applications of cryptography and how it is applied to various areas in the field of security. It describes and analyzes various unintended covert timing channels that are formed when. Network covert channels, tcpip, covert timing channels, detection 1.

Cryptography software is a type of computer program that is generally used to encode information. I have two asymmetricalgorithm objects that contain an rsa private and rsa public key. This can enable the safe transfer of communication between parties, or allow valuable information to be hidden. Introduction a covert channel is a mechanism that can be used to violate a security policy by allowing information to leak to an unauthorized process 14. They were all over this area but without a clear solution that wouldnt kill the performance or pricing. Classical cryptanalysis involves an interesting combination of analytical reasoning, application of mathematical tools, pattern finding, patience, determination, and luck. Timing and sidechannel countermeasures for quantumsafe cryptography william whyte, cto, onboard security.