Would the development of practical Quantum Computers or DNA computers break PGP?
Interesting question! Actually, this is two separate questions as DNA and Quantum computing affect the security of PGP in different ways. First, Quantum Computers (QC). If (and it’s a big “if” [Sch96a], [RSA96a]) QCs become practical then it is likely to have several implications in cryptography: • DL & IFP based PK systems can be broken in polynomial time [RSA96a] (e.g. QCs can factor and compute discrete logs of any size in polynomial time.) • Symmetric algorithms that support keys of insufficient length will be broken. Keys of 128-bit will be broken with the ease that 64-bit keys are broken today. It is thought that QC cannot break symmetric keys of 256-bits. (See Note 5 and [Dif98]). Of course, this comment also applies to hash functions. Professor Peter Knight, a lead physicist researching into QCs has commented that [Bro99] “It looks a long way of…if in four years we have worked out how to build a machine that uses quantum mechanics to factories 15, everyone will be hugely plea
