agreeing on a secret language diffie hellman
play

Agreeing on a secret language : Diffie-Hellman Bobs secret - PowerPoint PPT Presentation

Mar 08, 2023 •11 likes •81 views

Cryptography : how to talk in a secret language in public You broke ! my heart Agreeing on a secret language : Diffie-Hellman Bobs secret language Alices public lock box Only Alice Bob slams knows the the door combination

  1. Cryptography : how to talk in a secret language in public You broke ♥ ! my heart

  2. Agreeing on a secret language : Diffie-Hellman Bob’s secret language Alices’ public lock box Only Alice Bob slams knows the the door combination

  3. More dials means more possible combinations Attack times : D-H 768 bits: D-H 1024 bits: D-H 3072 bits: 37000y.CPU 45 000 000y.CPU ANSSI recommended [Source : Logjam paper (Adrian & al)] (Fill the solar system with CPUs and wait 10bn years)

  4. Weight and diversity issues Same security [ANSSI, RGS-Annexe B1] Ell. curve DH 256 bits DH 3072 bits Next attacks on First attack on DH : similar lock boxes: 45 000 000y.Cpu 0.1y.CPU Problem for 26 % Https sites & SSH servers Logjam paper :

  5. In real life : downgrade attacks on Diffie-Hellmann Bob, it’s Alice, Ok ! let’s use this small lock box Bob Alice False Alice FREAK – SLOTH – LogJam attacks on TLS See papers of K. Barghavan & al

  6. Listen to science while it is still time! The death of SHA-1’s hash function (1995) : 2005 2013 2017 Bursztein & al Stevens (Eurocrypt) Wang & al (CRYPTO) First real attack Theoretical weaknesses First theoretical attack https://shattered.io/ Firefox awakes

  7. Take-home points  Check/update your security every ~3 years with the recommendations : https://www.ssi.gouv.fr/uploads/2015/01/RGS_v-2-0_B1.pdf  And beyond standard cryptography: Fragmentation of secrets ● Blockchain ● « Trusted computing » (for dedicated tasks) ● … and be ready when research will provide ● post-quantum crypto solutions.

Recommend

Lecture Outline Review of Diffie-Hellman key exchange Looking at Authentication from a

Lecture Outline Review of Diffie-Hellman key exchange Looking at Authentication from a

Lecture Outline Review of Diffie-Hellman key exchange Looking at Authentication from a number of perspectives Today: authenticating users, services Agreeing on Secret Keys Without Prior Arrangement Diffie-Hellman Key Exchange

1.07k views • 73 slides
1 Diffie-Hellman exponential key exchange Diffie-Hellman exponential key exchange Alice has

1 Diffie-Hellman exponential key exchange Diffie-Hellman exponential key exchange Alice has

Symmetric cryptography Both parties must agree on a secret key, K message is encrypted, sent, decrypted at other side E K (P) D K (C) Secure Communication Bob Alice Key distribution must be secret otherwise messages can be

553 views • 10 slides
RSA Public Key CryptoSystem One way Trapdoor Functions Diffie and Hellman (76) New Directions

RSA Public Key CryptoSystem One way Trapdoor Functions Diffie and Hellman (76) New Directions

RSA Public Key CryptoSystem One way Trapdoor Functions Diffie and Hellman (76) New Directions in Cryptography Split the Bobs secret key K to two parts: K E , to be used for encrypting messages to Bob. K D , to be used for

482 views • 32 slides
Lecture 7 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography

Lecture 7 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography

Lecture 7 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography Asymmetric cryptography Invented in 1974-1978 (Diffie-Hellman and Rivest-Shamir- Adleman) Two keys: private (SK), public (PK) Encryption:

810 views • 42 slides
Lecture 8 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography

Lecture 8 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography

Lecture 8 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography Asymmetric cryptography Invented in 1974-1978 (Diffie-Hellman and Rivest-Shamir- Adleman) Two keys: private (SK), public (PK) Encryption: with

445 views • 17 slides
Lecture 8 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography

Lecture 8 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography

Lecture 8 Public Key Cryptography (Diffie-Hellman and RSA) 1 Public Key Cryptography Asymmetric cryptography Invented in 1974-1978 (Diffie-Hellman and Rivest-Shamir- Adleman) Two keys: private (SK), public (PK) Encryption:

256 views • 22 slides
Diffie-Hellman, discrete logs, the NSA, and you J. Alex Halderman University of Michigan Based

Diffie-Hellman, discrete logs, the NSA, and you J. Alex Halderman University of Michigan Based

Diffie-Hellman, discrete logs, the NSA, and you J. Alex Halderman University of Michigan Based on joint work: Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian, Karthikeyan Bhargavan, Zakir Durumeric, Pierrick Gaudry,

879 views • 63 slides
High-speed Diffie-Hellman, part 2 D. J. Bernstein University of Illinois at Chicago Classic

High-speed Diffie-Hellman, part 2 D. J. Bernstein University of Illinois at Chicago Classic

High-speed Diffie-Hellman, part 2 D. J. Bernstein University of Illinois at Chicago Classic question about the Diffie-Hellman system: How quickly can we compute n th powers mod p ? Modular exponentiation. p ; Assume standard prime p =

684 views • 45 slides
Public Key Infrastructure Chester Rebeiro IIT Madras Recollect Diffie-Hellman Key Exchange

Public Key Infrastructure Chester Rebeiro IIT Madras Recollect Diffie-Hellman Key Exchange

Public Key Infrastructure Chester Rebeiro IIT Madras Recollect Diffie-Hellman Key Exchange Key Establishment : Alice and Bob want to use a block cipher for encryption. How do they agree upon the secret key Alice and Bob agree upon a

972 views • 56 slides
C.c) DSA and Diffie-Hellman W. Schindler: Cryptography, B-IT, winter 2006 / 2007 2 C.73 DSA

C.c) DSA and Diffie-Hellman W. Schindler: Cryptography, B-IT, winter 2006 / 2007 2 C.73 DSA

1 C.c) DSA and Diffie-Hellman W. Schindler: Cryptography, B-IT, winter 2006 / 2007 2 C.73 DSA (Digital Signature Algorithm) standardized by NIST A) Generation of a key pair Select a prime q with 2 159 < q < 2 160 Select a

348 views • 11 slides
Diffie-Hellman not secure against Man-in-the-Middle-attack: Want to guarantee authenticity. Alice

Diffie-Hellman not secure against Man-in-the-Middle-attack: Want to guarantee authenticity. Alice

Diffie-Hellman not secure against Man-in-the-Middle-attack: Want to guarantee authenticity. Alice Mallory Bob Can achieve this with publc-key cryptography as well. g a a First example: Schnorr Signature g m m a 1024 bit

283 views • 3 slides
Diffie-Hellman not secure against Man-in-the-Middle-attack: Alice Mallory Bob g a a g

Diffie-Hellman not secure against Man-in-the-Middle-attack: Alice Mallory Bob g a a g

Diffie-Hellman not secure against Man-in-the-Middle-attack: Alice Mallory Bob g a a g m m g ma g ma g n n g b b g nb g nb g ma g ma , g nb g nb Eike Ritter Cryptography 2014/15 106

417 views • 9 slides
Public Key Cryptography Diffie-Hellman Others CSS441: Security and Cryptography Sirindhorn

Public Key Cryptography Diffie-Hellman Others CSS441: Security and Cryptography Sirindhorn

CSS441 Public Key Crypto Principles RSA Public Key Cryptography Diffie-Hellman Others CSS441: Security and Cryptography Sirindhorn International Institute of Technology Thammasat University Prepared by Steven Gordon on 20 December 2015

461 views • 29 slides
A Static Diffie-Hellman Attack on Several Direct Anonymous Attestation Schemes Ernie Brickell 1

A Static Diffie-Hellman Attack on Several Direct Anonymous Attestation Schemes Ernie Brickell 1

A Static Diffie-Hellman Attack on Several Direct Anonymous Attestation Schemes Ernie Brickell 1 Liqun Chen 2 Jiangtao Li 1 1. Intel Corporation, Hillsboro, Oregon, USA 2. Hewlett-Packard Laboratories, Bristol, UK InTrust 2012 Royal Holloway,

827 views • 17 slides
On the Static Diffie-Hellman Problem on Elliptic Curves over Extension Fields Robert Granger

On the Static Diffie-Hellman Problem on Elliptic Curves over Extension Fields Robert Granger

Background and Motivation Main Algorithm and Results On the Static Diffie-Hellman Problem on Elliptic Curves over Extension Fields Robert Granger rgranger@computing.dcu.ie Claude Shannon Institute, UCD and DCU, Ireland ASIACRYPT, 8th December

655 views • 48 slides
Measuring small subgroup attacks against Diffie-Hellman Luke Valenta , David Adrian ,

Measuring small subgroup attacks against Diffie-Hellman Luke Valenta , David Adrian ,

Measuring small subgroup attacks against Diffie-Hellman Luke Valenta , David Adrian , Antonio Sanso , Shaanan Cohney , Joshua Fried , Marcella Hastings , J. Alex Halderman , Nadia Heninger University of

461 views • 42 slides
Intro to Public Key Cryptography Diffie & Hellman Key Exchange Course Summary

Intro to Public Key Cryptography Diffie & Hellman Key Exchange Course Summary

Intro to Public Key Cryptography Diffie & Hellman Key Exchange Course Summary Introduction Stream & Block Ciphers Block Ciphers Modes (ECB,CBC,OFB) Advanced Encryption Standard (AES) Message

243 views • 20 slides
Curve25519: Which public-key systems new Diffie-Hellman speed records are smallest? Fastest? D.

Curve25519: Which public-key systems new Diffie-Hellman speed records are smallest? Fastest? D.

Curve25519: Which public-key systems new Diffie-Hellman speed records are smallest? Fastest? D. J. Bernstein Real-world cost measures: Pentium cycles, Athlon cycles, Thanks to: etc. for generating keys, signing, University of Illinois at

541 views • 35 slides
Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian, Karthikeyan

Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian, Karthikeyan

Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian, Karthikeyan Bhargavan, Zakir Durumeric, Pierrick Gaudry, Matthew Green, J. Alex Halderman, Nadia Heninger, Drew Springall, Emmanuel Thom e, Luke Valenta, Benjamin

1.01k views • 34 slides
The computational and decisional Diffie-Hellman assumptions in CryptoVerif Bruno Blanchet and

The computational and decisional Diffie-Hellman assumptions in CryptoVerif Bruno Blanchet and

Basic DDH Basic CDH Need for extension Extended CDH Extended DDH Conclusion The computational and decisional Diffie-Hellman assumptions in CryptoVerif Bruno Blanchet and David Pointcheval CNRS, Ecole Normale Sup erieure, INRIA, Paris

226 views • 22 slides
Diffie-Hellman Key Exchange Source: Wikipedia ElGamal Key Generator Generate primes p and

Diffie-Hellman Key Exchange Source: Wikipedia ElGamal Key Generator Generate primes p and

Diffie-Hellman Key Exchange Source: Wikipedia ElGamal Key Generator Generate primes p and q as well as an element g Z p that generates the subgroup G q . Choose a random x from { 0 , . . . , q 1 } . Compute h = g x .

754 views • 7 slides
Fast FPGA Implementation of Diffie-Hellman on the Kummer Surface of a Genus-2 Curve Philipp

Fast FPGA Implementation of Diffie-Hellman on the Kummer Surface of a Genus-2 Curve Philipp

Fast FPGA Implementation of Diffie-Hellman on the Kummer Surface of a Genus-2 Curve Philipp Koppermann, Fabrizio De Santis, Johann Heyszl and Georg Sigl History of High-Speed Curve Cryptography over Prime Fields 1 Point Addition on a

319 views • 16 slides
E -th roots and static Diffie-Hellman using index calculus Antoine Joux 1 Joint work with Reynald

E -th roots and static Diffie-Hellman using index calculus Antoine Joux 1 Joint work with Reynald

E -th roots and static Diffie-Hellman using index calculus Antoine Joux 1 Joint work with Reynald Lercier 2 , David Naccache 3 , Emmanuel Thom e 4 Elliptic Curve Cryptography 2008 Utrecht 1 DGA and UVSQ 2 DGA and IRMAR 3 ENS 4 INRIA Lorraine 1

538 views • 25 slides
The LOGJAM attack Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian,

The LOGJAM attack Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian,

The LOGJAM attack Imperfect Forward Secrecy: How Diffie-Hellman Fails in Practice David Adrian, Karthikeyan Bhargavan, Zakir Durumeric, Pierrick Gaudry, Matthew Green, J. Alex Halderman, Nadia Heninger, Drew Springall, Emmanuel Thom e, Luke

674 views • 45 slides

More recommend