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Speaking with Cryptographic Oracles

Daniel Crowley

Daniel Crowley explores speaking with cryptographic oracles at DEF CON 19, examining cryptographic-oracles and practical defenses.

Summary

Architecture and Background

Speaking with Cryptographic Oracles DANIEL CROWLEY APPLICATION SECURITY CONSULTANT, TRUSTWAVE - SPIDERLABS Cryptography is often used to secure data, but few people have a solid understanding of cryptography. It is often said that if you are not strictly a cryptographer, you will get cryptography wrong. For that matter, if you ARE a cryptographer, it is still easy to make mistakes.

Vulnerability Analysis

The algorithms might be peer reviewed and unbroken for 15 years, but if you use them incorrectly, they might leak information. Cryptographic oracles are systems which take user-controlled input and leak part or all of the output, generally leading to an attacker being able to defeat the cryptography, in part of in whole. In this talk, methods for finding and exploiting encryption, decryption, and padding oracles with minimal cryptographic knowledge will be discussed.

Exploitation and Demonstrations

Daniel Crowley is an Application Security Consultant for Trustwave's SpiderLabs team. He has been working in the information security industry for over 6 years and has been focused on penetration testing, specifically on Web applications. Daniel is particularly interested in vulnerabilities caused by a failure to account for little known or even undocumented properties of the platforms on which applications run.

Remediation and Defensive Strategies

He especially enjoys playing around with Web based technologies and physical security technologies and techniques. Dan also rock climbs and makes a mean chili. Twitter: @dan_crowley.

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