Bleichenbacher's Oracle: How to break RSA encryption with PKCS #1 v1.5 (1998)

Guarda su YouTube → 1:15:48 29 marzo 2022

Descrizione

In this video I explain a famous cryptographic attack known as Bleichenbacher's oracle that was found in 1998 by Daniel Bleichenbacher and that attacks vulnerable implementation of RSA encryption when used with a padding standard known as PKCS #1 v1.5 that expose a cryptographic padding oracle. Btw after recording the video I realized that the way I pronounced “bleichenbacher” throughout the entire video is wrong. Sorry for that :/ ------------------------------------ ORIGINAL MATERIAL: https://academy.leonardotamiano.xyz/video/HgrwrDMvRTI.html https://archive.leonardotamiano.xyz/yt/crypto/01/ ------------------------------------ EXTERNAL REFERENCES: http://archiv.infsec.ethz.ch/education/fs08/secsem/bleichenbacher98.pdf https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/Experimenting%20with%20the%20Bleichenbacher%20Attack%20-%20Livia%20Capol.pdf https://www.youtube.com/watch?v=iA6OevUmeHk http://secgroup.dais.unive.it/wp-content/uploads/2012/11/Practical-Padding-Oracle-Attacks-on-RSA.html#eq1 ------------------------------------ TIMESTAMPS: 00:00:00 introduction 00:06:30 brief recap of TLS and TLS handshake 00:11:15 brief recap on RSA 00:14:28 on the malleability of RSA 00:16:15 textbook RSA does not work 00:17:30 on the padding scheme PKCS #1 v1.5 00:21:48 what does it mean to have a bleichenbacher's oracle? 00:25:39 overview of the bleichenbacher's attack 00:30:08 on the consequences of PKCS #1 v1.5 00:33:27 start of decryption algorithm 00:35:35 step 1: search for next s_i 00:38:37 step 2: construction of M_i 00:56:11 step 2: code 00:57:30 after the step 2 00:58:50 classical optimization #1 01:02:30 classical optimization #2 01:08:15 further optimizations 01:09:00 the missing step 01:09:50 references 01:10:10 offline implementation in python ---------------------------------- FOR CONTACTS: - Website: https://leonardotamiano.xyz - Academy: https://academy.leonardotamiano.xyz - Email: leonardotamiano95@gmail.com

Commenti 11

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@0xbro 29 marzo 2022 2

Un Leonardo in versione international! Attacco molto interessante btw! Non ho ancora finito di vederlo tutto ma nei prossimi giorni di sicuro lo concluderò
@Daniel-ng8fi 26 marzo 2025

This video was fantastic and filled in the gaps I desperately needed filled in. Thank you so much for taking the time to make this!!!
1 risposta
1. @esadecimale Autore 26 marzo 2025
  
  That’s precious!
@laemmad 8 febbraio 2026

This helped alot. Thank you for explaining. :)
@ballban 23 marzo 2024 1

omg it's so easy to understand, thank u so much for such a great video!
1 risposta
1. @esadecimale Autore 24 marzo 2024 1
  
  Thank you! Checkout my english channel, where I focus on penetration testing, applied cryptography, and other Computer Science related matter: https://www.youtube.com/channel/UCzPk3Dj63B6PIEifvVvDfBg
@esadecimale Autore 6 aprile 2022

Btw, as it is stated in the sympy documentation: “”” This module is intended for educational purposes only. Do not use the functions in this module for real cryptographic applications. “”” I used sympy just because I also needed to generate keys of very low sizes, something that the famous public crypto APIs such as openSSL do not let you do. (Which is a wise choice imo) The attack however works also for crypto secure keys, the only thing that may differ is the performance, maybe, that is the number of oracle calls needed to complete the attack.
@buildlackey 10 dicembre 2023

great job explaining ! step by step. and you did it in English. impressive ;^)
1 risposta
1. @esadecimale Autore 12 dicembre 2023
  
  thank you, recently I’ve made an english channel as well, you can find it under the name “hexdump” if you are interested in more of this!
@andreapepe1636 29 marzo 2022 1

Ciao, bel video... Quando fai le macchine HTB che editor usi per redigere i report? È un editor markdown?
1 risposta
1. @esadecimale Autore 29 marzo 2022 1
  
  Utilizzo Emacs, ho una intera playlist dedicata, si chiama proprio “Emacs” quindi la dovresti trovare facilmente e dovrebbe rispondere almeno in parte ai tuoi dubbi :p