The RSA Conference, with over 15,000 attendees and 300 exhibitors, is the largest computer security event of the year. The Cryptographers’ Track (CT- RSA) is a research conference within the RSA Conference. Starting in 2001, CT-RSA continues to its seventh year and is now regarded as one of the major regularly staged event for presenting the results of cryptographic research to a wide variety of audiences. The proceedings of CT-RSA 2007 contain 25 papers selected from 73 s- missions which cover all the topics of cryptography. All the submissions were reviewed by at least three reviewers, which was possible by the hard work of 23 Program Committee members and many external reviewers listed in the foll- ing pages. The papers were selected as a result of conscientious discussion. The program includes two invited talks, by Michel Rabin and Andrew Odlyzko. I would like to express my gratitude to the Program Committee members, whowereenthusiasticfromtheverybeginningofthis completedproject.Thanks also to the external reviewers including those who completed urgent reviews during the discussion phase. Special thanks to Shai Halevi for providing and maintaining the Web review system. Finally, I would like to thank Burt Kaliski of RSA Laboratories and the Steering Committee for their suggestions and c- tinuous assistance.

Table of Contents:
Symmetric-Key Encryption.- MV3: A New Word Based Stream Cipher Using Rapid Mixing and Revolving Buffers.- A Simple Related-Key Attack on the Full SHACAL-1.- Signatures and Authentication.- Impossibility Proofs for RSA Signatures in the Standard Model.- Selecting Secure Passwords.- Human Identification Through Image Evaluation Using Secret Predicates.- Hash Functions.- Cryptanalysis of Reduced Variants of the FORK-256 Hash Function.- Second Preimages for SMASH.- Digital Signatures (I).- A Practical Optimal Padding for Signature Schemes.- Directed Transitive Signature Scheme.- Identity-Based Multi-signatures from RSA.- Cryptographic Protocols (I).- Improved Efficiency for Private Stable Matching.- Compact E-Cash from Bounded Accumulator.- Batch Processing of Interactive Proofs.- Side-Channel Attacks (I).- Timing Attacks on NTRUEncrypt Via Variation in the Number of Hash Calls.- Predicting Secret Keys Via Branch Prediction.- Side-Channel Attacks (II).- Template Attacks on Masking—Resistance Is Futile.- Differential Power Analysis of Stream Ciphers.- Cache Based Remote Timing Attack on the AES.- Cryptographic Protocols (II).- Group Secret Handshakes Or Affiliation-Hiding Authenticated Group Key Agreement.- Efficient Password-Authenticated Key Exchange Based on RSA.- Non-degrading Erasure-Tolerant Information Authentication with an Application to Multicast Stream Authentication over Lossy Channels.- Digital Signatures (II).- A Practical and Tightly Secure Signature Scheme Without Hash Function.- How to Strengthen Any Weakly Unforgeable Signature into a Strongly Unforgeable Signature.- Efficient Implementation.- Public Key Cryptography and RFID Tags.- A Bit-Slice Implementation of the Whirlpool Hash Function.