scholarly journals Towards an Analysis of Passive Attacks on Anonymous Communication Systems

2016 ◽  
Vol 10 (8) ◽  
pp. 1-12
Author(s):  
Tianbo Lu ◽  
Pan Gao ◽  
Lingling Zhao ◽  
Yang Li ◽  
WanJiang Han
Keyword(s):  
Communication Systems ◽  
Anonymous Communication ◽  
Anonymous Communication Systems

Protecting User’s Privacy from Browser-Based Attacks

2014 ◽  
Vol 631-632 ◽  
pp. 941-945
Author(s):  
Gao Feng He ◽  
Tao Zhang ◽  
Yuan Yuan Ma ◽  
Jia Xuan Fei
Keyword(s):  
Communication Systems ◽  
Anonymous Communication ◽  
Web Pages ◽  
Main Observation ◽  
Execution Times ◽  
Anonymous Communication Systems ◽  
Mozilla Firefox ◽  
Set Up ◽  
Browsing Behavior

Recently there has been a new kind of attacks, browser-based attacks, against anonymous communication systems, such as Tor. This kind of attacks exploits JavaScript in the browser or the HTML meta refresh to generate some predefined signals to correlate users and their visited websites. A novel and efficient defense against such attacks is proposed in this paper. Our main observation is that the attacker must generate enough signals from the client site (the browser) to correlate the user and the website while we can detect the attack at the client site. More specifically, when a user is browsing a specific website and a browser-based attack is in progress, the number of outgoing flows and the total byte counts generated by the browser should be much larger compared with the normal browsing behavior. So we can set up fingerprints (number of outgoing flows and total byte counts) for normal browsing of web pages for a period of time and utilize these fingerprints to detect browser-based attacks. We have also found that some JavaScript codes must be executed many times if the attacker uses JavaScript to communicate. We have modified the Mozilla Firefox JavaScript engine to audit execution times of JavaScript code to defend these attacks, including browser-based attacks.

Anonymous Communication

2012 ◽  
pp. 101-123
Keyword(s):  
Communication Systems ◽  
Anonymous Communication ◽  
Onion Routing ◽  
Symmetric Key ◽  
Anonymous Communication Systems

Schemes of anonymous communication enable entities to send or receive their messages without disclosing their identities to others including managers of communication systems and receivers or senders of the messages. Among various existing schemes this chapter introduces Crowds, DC net, Mix-net, ESEBM (Enhanced Symmetric key Encryption Based Mix-Net), and Onion Routing. Mechanisms to protect anonymous communication systems from malicious entities are also discussed.

Encryption Schemes for Anonymous Systems

2012 ◽  
pp. 26-45
Keyword(s):  
Linear Equation ◽  
Communication Systems ◽  
Anonymous Communication ◽  
Voting Systems ◽  
Individual Values ◽  
Encrypted Data ◽  
Encrypt Data ◽  
Encryption Schemes ◽  
Elgamal Encryption ◽  
Anonymous Communication Systems

As encryption schemes useful in developing secure anonymous systems, linear equation based encryption, probabilistic, commutative and verifiable re-encryption, and threshold ElGamal encryption schemes are introduced. Linear equation based encryption functions are additive, and they enable entities to calculate sums of data owned by others without knowing individual values, and probabilistic, commutative and verifiable re-encryption functions enable entities to encrypt data while concealing the correspondences between encrypted data and their decrypted forms from anyone including the owners of the data. Finally, threshold ElGamal encryption functions disable entities to decrypt encrypted data without the cooperation among t out of n authorities (t = n), while ensuring correct decryptions when at least t authorities are honest. All encryption schemes are extensively used in the following parts of this book, e.g. for developing anonymous communication systems, anonymous authentication systems, electronic payment, procurement, and voting systems.

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