A Key Recovery Attack on MDPC with CCA Security Using Decoding Errors

Learn about a key recovery attack on QC-MDPC codes with CCA security in this 23-minute conference talk from Asiacrypt 2016. Explore the motivation behind QC-MDPC codes, their use in public-key cryptography, and the CCA-secure version. Delve into iterative decoding using Gallager's bit-flipping strategy and understand the key-related property of distance spectrum. Examine the main observation and attack scenarios for both plain QC-MDPC and CCA-secure QC-MDPC. Gain insights into the distinguishing procedure, results for obtaining distance spectrum in the CPA case, and final remarks on this cryptographic research.

Intro
Outline
Motivation
QC-MDPC Codes
The QC-MDPC PKC Scheme
CCA-Secure Version
Iterative Decoding: Gallager's Bit-Flipping Strategy
Basic Scenario
Key-Related Property: Distance Spectrum (DS)
Main Observation
On Plain QC-MDPC (CPA)
Attack on CCA-Secure QC-MDPC
An Explanation for the Distinguishing Procedure
Results Obtaining DS in the CPA Case
Final Remarks