Quantifying the problem
How secure is a cipher? How weak is a key? How ‘hidden’ is encrypted data? Here, we begin to investigate the ways we can put numbers on such aspects and so better evaluate and compare algorithms.
Read the worked example on how these ciphers were broken and then make use of your new understanding to break the secret messages posted by the others in week 1.
Discuss the problem of cryptography being broken in the future. Just because it is unbreakable now, doesn’t mean it will always be the case. The WhatsApp messages of today’s teenagers might not contain any revelations if they are made transparent a decade after they were sent, but what would happen if a technological advance in the next 10 years makes industrial or military secrets suddenly accessible?
Fee paying students may wish to read the resource in the See also section at the end of this step to enhance your understanding of applied cryptography.
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