Play Video
1
3 - 2 - The Data Encryption Standard -Cryptography-Professor Dan Boneh
3 - 2 - The Data Encryption Standard -Cryptography-Professor Dan Boneh
::2012/04/16::
Play Video
2
symmetric key cryptography
symmetric key cryptography
::2014/08/06::
Play Video
3
Simplified DES Example (CSS322, Lecture 5, 2013)
Simplified DES Example (CSS322, Lecture 5, 2013)
::2013/11/26::
Play Video
4
A New selective image encryption approach
A New selective image encryption approach
::2014/06/11::
Play Video
5
Car Key Master CKM200 write key for Benz DAS2
Car Key Master CKM200 write key for Benz DAS2
::2014/03/07::
Play Video
6
Is Transparent Data Encryption a Good Choice for Your Data?
Is Transparent Data Encryption a Good Choice for Your Data?
::2014/07/29::
Play Video
7
Lecture 8: Advanced Encryption Standard (AES) by Christof Paar
Lecture 8: Advanced Encryption Standard (AES) by Christof Paar
::2014/01/30::
Play Video
8
DATA ENCRYPTION STANDARD (DES) netwinz
DATA ENCRYPTION STANDARD (DES) netwinz
::2011/06/17::
Play Video
9
Mod-01 Lec-11 Block Cipher Standards (DES)
Mod-01 Lec-11 Block Cipher Standards (DES)
::2012/05/17::
Play Video
10
Encrypt your data on the Cloud
Encrypt your data on the Cloud
::2012/07/15::
Play Video
11
Data Encryption Standard
Data Encryption Standard
::2014/08/13::
Play Video
12
Why the NSA is breaking our encryption -- and why we should care | Matthew Green | TEDxMidAtlantic
Why the NSA is breaking our encryption -- and why we should care | Matthew Green | TEDxMidAtlantic
::2014/10/20::
Play Video
13
DES Encryption using OpenSSL
DES Encryption using OpenSSL
::2012/01/31::
Play Video
14
ATM Encrypted Pin Pad Autopsy
ATM Encrypted Pin Pad Autopsy
::2014/06/22::
Play Video
15
Introduction to Encryption Techniques (CSS322, Lecture 2, 2013)
Introduction to Encryption Techniques (CSS322, Lecture 2, 2013)
::2013/11/14::
Play Video
16
How NOT to Store Passwords! - Computerphile
How NOT to Store Passwords! - Computerphile
::2013/11/20::
Play Video
17
NSA cracked most online encryption
NSA cracked most online encryption
::2013/09/14::
Play Video
18
Fundamentals of Next Generation Encryption
Fundamentals of Next Generation Encryption
::2012/11/08::
Play Video
19
WD My Passport 2TB - Hardware Encryption (Review)
WD My Passport 2TB - Hardware Encryption (Review)
::2013/09/29::
Play Video
20
05 | Advanced C#, Type and Value Validation; Encryption Techniques
05 | Advanced C#, Type and Value Validation; Encryption Techniques
::2013/11/15::
Play Video
21
Understanding Export Controls for Encryption Items
Understanding Export Controls for Encryption Items
::2012/03/16::
Play Video
22
RSA Key Generation, Signatures and Encryption using OpenSSL
RSA Key Generation, Signatures and Encryption using OpenSSL
::2012/03/15::
Play Video
23
Survival tip: Sensitive data storage, backup and encryption
Survival tip: Sensitive data storage, backup and encryption
::2014/02/18::
Play Video
24
Encryption All server 0 60 Clean c#
Encryption All server 0 60 Clean c#
::2014/05/15::
Play Video
25
Designing an Efficient Image Encryption-Then Compression System via Prediction Error Clustering
Designing an Efficient Image Encryption-Then Compression System via Prediction Error Clustering
::2014/09/02::
Play Video
26
How to Encrypt or Decrypt String with password protected in VB.NET
How to Encrypt or Decrypt String with password protected in VB.NET
::2013/12/12::
Play Video
27
Encryption Box on Security Accreditations and trusting UKFast with their Future
Encryption Box on Security Accreditations and trusting UKFast with their Future
::2013/11/26::
Play Video
28
PGP Desktop Tutorial
PGP Desktop Tutorial
::2007/10/31::
Play Video
29
CSS322, Lecture 21, 25 Jan 2013 - Key Management with Symmetric Encryption
CSS322, Lecture 21, 25 Jan 2013 - Key Management with Symmetric Encryption
::2013/01/25::
Play Video
30
INTERNATIONAL JOURNAL Multi Level Steganographic Algorithm for Audio Steganography using LSB, Parity
INTERNATIONAL JOURNAL Multi Level Steganographic Algorithm for Audio Steganography using LSB, Parity
::2014/05/24::
Play Video
31
Final Year Projects | A Secure Image Based Steganographic Model Using RSA Algorithm and LSB I
Final Year Projects | A Secure Image Based Steganographic Model Using RSA Algorithm and LSB I
::2013/05/13::
Play Video
32
NASA LOOSES International SPACE STATION Codes on STOLEN LAPTOP
NASA LOOSES International SPACE STATION Codes on STOLEN LAPTOP
::2012/03/03::
Play Video
33
CSS322, Lecture 22, 25 Jan 2013 - Key Management with Symmetric Encryption
CSS322, Lecture 22, 25 Jan 2013 - Key Management with Symmetric Encryption
::2013/01/25::
Play Video
34
What About CrashPlan?
What About CrashPlan?
::2012/01/21::
Play Video
35
22C3 modern disk encryption
22C3 modern disk encryption
::2013/03/24::
Play Video
36
Robust Correlation of Encrypted Attack Traffic Through Stepping Stones by Flow Watermarking
Robust Correlation of Encrypted Attack Traffic Through Stepping Stones by Flow Watermarking
::2012/11/03::
Play Video
37
Crypto Voip
Crypto Voip
::2013/08/28::
Play Video
38
Samsung Galaxy S4: How to Encrypt Outgoing Email
Samsung Galaxy S4: How to Encrypt Outgoing Email
::2013/07/19::
Play Video
39
encryption تشفير قاعده البيانات
encryption تشفير قاعده البيانات
::2010/03/14::
Play Video
40
Diffie-Hellman Algorithm Explained
Diffie-Hellman Algorithm Explained
::2013/10/01::
Play Video
41
"Encryption" Official Film Teaser 2012
"Encryption" Official Film Teaser 2012
::2012/04/04::
Play Video
42
Promat Video Identification Parade Software Demonstration
Promat Video Identification Parade Software Demonstration
::2014/03/03::
Play Video
43
Kevin Slavin Those Algorithms That Govern Our Lives Video
Kevin Slavin Those Algorithms That Govern Our Lives Video
::2011/08/03::
Play Video
44
What Can We Learn from Edward Snowden
What Can We Learn from Edward Snowden
::2014/06/17::
Play Video
45
International Journal of Chaos, Control, Modelling and Simulation (IJCCMS)
International Journal of Chaos, Control, Modelling and Simulation (IJCCMS)
::2014/01/27::
Play Video
46
German companies to automatically encrypt emails
German companies to automatically encrypt emails
::2013/08/09::
Play Video
47
HAR 2009: Life or Death Cryptology 1/5
HAR 2009: Life or Death Cryptology 1/5
::2009/10/11::
Play Video
48
HAR 2009: Life or Death Cryptology 2/5
HAR 2009: Life or Death Cryptology 2/5
::2009/10/11::
Play Video
49
Molecular Algorithms for Satisfiability
Molecular Algorithms for Satisfiability
::2012/10/11::
Play Video
50
HAR 2009: Life or Death Cryptology 4/5
HAR 2009: Life or Death Cryptology 4/5
::2009/10/12::
NEXT >>
RESULTS [51 .. 101]
From Wikipedia, the free encyclopedia
Jump to: navigation, search
IDEA
International Data Encryption Algorithm InfoBox Diagram.svg
An encryption round of IDEA
General
Designers Xuejia Lai and James Massey
Derived from PES
Successors MMB, MESH, Akelarre,
IDEA NXT (FOX)
Cipher detail
Key sizes 128 bits
Block sizes 64 bits
Structure Lai-Massey scheme
Rounds 8.5
Best public cryptanalysis
The key can be recovered with a computational complexity of 2126.1 using narrow bicliques. This attack is computationally faster than a full brute force attack, though not, as of 2013, computationally feasible.[1]

In cryptography, the International Data Encryption Algorithm (IDEA), originally called Improved Proposed Encryption Standard (IPES), is a symmetric-key block cipher designed by James Massey of ETH Zurich and Xuejia Lai and was first described in 1991. The algorithm was intended as a replacement for the Data Encryption Standard (DES). IDEA is a minor revision of an earlier cipher, Proposed Encryption Standard (PES).

The cipher was designed under a research contract with the Hasler Foundation, which became part of Ascom-Tech AG. The cipher was patented in a number of countries but was freely available for non-commercial use. The name “IDEA” is also a trademark. The last patents expired in 2012 and IDEA is now patent-free and thus free to use.[2][3]

IDEA was used in Pretty Good Privacy (PGP) v2.0, and was incorporated after the original cipher used in v1.0, BassOmatic, was found to be insecure.[4] IDEA is an optional algorithm in the OpenPGP standard.

Operation[edit]

IDEA operates on 64-bit blocks using a 128-bit key, and consists of a series of eight identical transformations (a round, see the illustration) and an output transformation (the half-round). The processes for encryption and decryption are similar. IDEA derives much of its security by interleaving operations from different groupsmodular addition and multiplication, and bitwise eXclusive OR (XOR) — which are algebraically "incompatible" in some sense. In more detail, these operators, which all deal with 16-bit quantities, are:

  • Bitwise eXclusive OR (denoted with a blue circled plus ).
  • Addition modulo 216 (denoted with a green boxed plus ).
  • Multiplication modulo 216+1, where the all-zero word (0x0000) in inputs is interpreted as 216 and 216 in output is interpreted as the all-zero word (0x0000) (denoted by a red circled dot ).

After the eight rounds comes a final “half round”, the output transformation illustrated below (the swap of the middle two values cancels out the swap at the end of the last round, so that there is no net swap):

International Data Encryption Algorithm InfoBox Diagram Output Trans.png

Structure[edit]

The overall structure of IDEA follows the Lai-Massey scheme. XOR is used for both subtraction and addition. IDEA uses a key-dependent half-round function. To work with 16 bit words (meaning four inputs instead of two for the 64 bit block size), IDEA uses the Lai-Massey scheme twice in parallel, with the two parallel round functions being interwoven with each other. To ensure sufficient diffusion, two of the sub-blocks are swapped after each round.

Key schedule[edit]

Each round uses six 16-bit sub-keys, while the half-round uses four, a total of 52 for 8.5 rounds. The first eight sub-keys are extracted directly from the key, with K1 from the first round being the lower sixteen bits; further groups of eight keys are created by rotating the main key left 25 bits between each group of eight. This means that it is rotated less than once per round, on average, for a total of six rotations.

Decryption[edit]

Decryption works like encryption, but the order of the round keys is inverted, and each value of subkeys K1 – K4 is replaced by its inverse for the respective group operation.

Security[edit]

The designers analysed IDEA to measure its strength against differential cryptanalysis and concluded that it is immune under certain assumptions. No successful linear or algebraic weaknesses have been reported. As of 2007, the best attack which applied to all keys could break IDEA reduced to 6 rounds (the full IDEA cipher uses 8.5 rounds).[5] Note that a "break" is any attack which requires less than 2128 operations; the 6-round attack requires 264 known plaintexts and 2126.8 operations.

Bruce Schneier thought highly of IDEA in 1996, writing, "In my opinion, it is the best and most secure block algorithm available to the public at this time." (Applied Cryptography, 2nd ed.) However, by 1999 he was no longer recommending IDEA due to the availability of faster algorithms, some progress in its cryptanalysis, and the issue of patents.[6]

In 2012, full 8.5 round IDEA was finally broken, using a narrow-bicliques attack, with a reduction of cryptographic strength of about two bits, similar to the effect of the previous bicliques attack on AES.[7]

Weak keys[edit]

The very simple key schedule makes IDEA subject to a class of weak keys; some keys containing a large number of 0 bits produce weak encryption.[8] These are of little concern in practice, being sufficiently rare that they are unnecessary to avoid explicitly when generating keys randomly. A simple fix was proposed: exclusive-ORing each subkey with a 16-bit constant, such as 0x0DAE.[8][9]

Larger classes of weak keys were found in 2002.[10]

This is still of negligible probability to be a concern to a randomly chosen key, and some of the problems are fixed by the constant XOR proposed earlier, but the paper is not certain if all of them are. A more comprehensive redesign of the IDEA key schedule may be desirable.[10]

Availability[edit]

A patent application for IDEA was first filed in Switzerland (CH A 1690/90) on May 18, 1990, then an international patent application was filed under the Patent Cooperation Treaty on May 16, 1991. Patents were eventually granted in Austria, France, Germany, Italy, the Netherlands, Spain, Sweden, Switzerland, the United Kingdom, (European Patent Register entry for European patent no. 0482154, filed May 16, 1991, issued June 22, 1994 and expired May 16, 2011), the United States (U.S. Patent 5,214,703, issued May 25, 1993 and expired January 7, 2012) and Japan (JP 3225440) (expired May 16, 2011 ).[11]

MediaCrypt AG is now offering a successor to IDEA and focuses on its new cipher (official release on May 2005) IDEA NXT, which was previously called FOX.

Literature[edit]

  • Hüseyin Demirci, Erkan Türe, Ali Aydin Selçuk, A New Meet in the Middle Attack on The IDEA Block Cipher, 10th Annual Workshop on Selected Areas in Cryptography, 2004.
  • Xuejia Lai and James L. Massey, A Proposal for a New Block Encryption Standard, EUROCRYPT 1990, pp389–404
  • Xuejia Lai and James L. Massey and S. Murphy, Markov ciphers and differential cryptanalysis, Advances in Cryptology — Eurocrypt '91, Springer-Verlag (1992), pp17–38.

References[edit]

  1. ^ http://www.cs.bris.ac.uk/eurocrypt2012/Program/Tues/Rechberger.pdf
  2. ^ "Espacenet - Bibliografische Daten" (in German). Worldwide.espacenet.com. Retrieved 2013-06-15. 
  3. ^ "Espacenet - Bibliografische Daten" (in German). Worldwide.espacenet.com. Retrieved 2013-06-15. 
  4. ^ Garfinkel, Simson (December 1, 1994), PGP: Pretty Good Privacy, O'Reilly Media, pp. 101–102, ISBN 978-1-56592-098-9 
  5. ^ Biham, E.; Dunkelman, O.; Keller, N. "A New Attack on 6-Round IDEA". "Proceedings of Fast Software Encryption, 2007, Lecture Notes in Computer Science". Springer-Verlag. 
  6. ^ "Slashdot: Crypto Guru Bruce Schneier Answers". slashdot.org. Retrieved 2010-08-15. 
  7. ^ Khovratovich, D.; Leurent, G.; Rechberger, C. "Narrow-Bicliques: Cryptanalysis of Full IDEA". "Advances in Cryptology – EUROCRYPT 2012". Springer-Verlag.  (subscription required)
  8. ^ a b Daemen, Joan; Govaerts, Rene; Vandewalle, Joos (1993), Weak Keys for IDEA, Advances in Cryptology, CRYPTO 93 Proceedings: 224–231 
  9. ^ Nakahara, Jorge Jr.; Preneel, Bart; Vandewalle, Joos (2002), A note on Weak Keys of PES, IDEA and some Extended Variants 
  10. ^ a b Biryukov, Alex; Nakahara, Jorge Jr.; Preneel, Bart; Vandewalle, Joos, New Weak-Key Classes of IDEA, Information and Communications Security, 4th International Conference, ICICS 2002, Lecture Notes in Computer Science 2513: 315–326, "While the zero-one weak keys problem of IDEA can be corrected just by XORing a fixed constant to all the keys (one such constant may be 0DAEx as suggested in [4]) the problem with the runs of ones may still remain and will require complete redesign of the IDEA key schedule." 
  11. ^ "GnuPG 1.4.13 released". Werner Koch. Retrieved 2013-10-06. 

External links[edit]

Wikipedia content is licensed under the GFDL License
Powered by YouTube
LEGAL
  • Mashpedia © 2014