Legacy Versus Security – a Cryptographic Dilemma

Image by Datacorp Technology Ltd

Image by Datacorp Technology Ltd

The June talk will be given by Prof Chris Mitchell of Royal Holloway, University of London. Chris will be talking about his research into cryptography, encryption and ciphers.

The Data Encryption Standard (DES), a US standard cipher algorithm, is now over 40 years old.  Not surprisingly, despite breaking new ground when it was published in the 1970s, it is no longer fit for purpose. However it remains in widespread use, albeit typically as ‘triple DES’ where data is ciphered three times to give added security.  Even triple DES is known to be weak.

This talk will summarise the history of the cipher, its strengths and weaknesses, and why we are still using it despite the availability of many more secure, and widely standardised, alternatives.  It turns out that re-engineering existing systems to incorporate new ciphers is sometimes almost impossibly difficult, largely because no provisions were made to allow for change in the original design.  The talk will conclude with a review of what this means for the future, when many other ciphers, currently in widespread use, will need to be replaced should quantum computers become a practical reality.

Chris Mitchell has been a Professor of Computer Science at Royal Holloway, University of London since 1990, where he co-founded one of the world’s largest and best known academic research groups in Information Security.  He has worked on cryptography and security throughout his career, which started when he joined Racal in Salisbury in 1979 after gaining his PhD in Mathematics.  He recently showed that the widely used triple-DES cipher is even less secure than previously thought.