Chapter XI: Public Key Cryptology
The coding schemes described in Chapter IV relied on a keyword or a code book and The Enigma Device depended on precise setup instructions. Such keys or instructions can be stolen or intercepted demolishing their usefulness. Enter public-key cryptosystems.
In such systems both the encryption key and the algorithm or method used to decode the message are public - not kept secret. To decrypt a message the decoder needs to know two large prime numbers (kept very secret). The coder is told the product of the two numbers. However if the primes are large enough there is no known way to find them except by brute force -- which could take hundreds of years with the fastest know computers.
In such systems both the encryption key and the algorithm or method used to decode the message are public - not kept secret. To decrypt a message the decoder needs to know two large prime numbers (kept very secret). The coder is told the product of the two numbers. However if the primes are large enough there is no known way to find them except by brute force -- which could take hundreds of years with the fastest know computers.
One method is known as RSA -- made of the initial letters of the surnames of Ron Rivest, Adi Shamir, and Leonard Adlerman who first publicly described the algorithm in 1977. The trio won the 2002 A. M. Turing Award, considered the “Nobel Prize of Computing”, for their contributions to public key cryptography. The Turing Award carries a $100,000 prize, with funding provided by Intel Corporation.
Clifford Cocks, an English mathematician working for the UK intelligence agency GCHQ, developed an equivalent system in 1973, but it was not declassified until 1997. |
Public Key Cryptosystems changed the security landscape overnight. Up until 1977 it had been a cat and mouse game between coders and decoders. Suddenly it became possible to create a mouse that was for all practical purposes uncatchable. It was like someone had devised armor plating that no conceivable shell could penetrate. This made it infinitely easier to keep information secret or to send it secretly.
The US government was alarmed by this and tried to arm twist various players into devising coding schemes with two decryption methods -- one known only to the government. This essentially allowed the government to read all otherwise secret messages. Backdoors are also frequently used by hackers to compromise coding systems for their own nefarious purposes..
The US government was alarmed by this and tried to arm twist various players into devising coding schemes with two decryption methods -- one known only to the government. This essentially allowed the government to read all otherwise secret messages. Backdoors are also frequently used by hackers to compromise coding systems for their own nefarious purposes..