Hyderabad, Sept 20: A tamper proof system developed by an Indian scientist and his colleagues at Massachusetts Institute of Technology in the United States is expected to provide high security to electronic transactions with credit cards. Modern cryptographic practice relies on number theory. When one sends his credit card number over the Internet, the string of digits is transformed -- encrypted -- by a mathematical function called a one-way function, which takes the credit card number and converts it into a fixed-length output number.

The one-way functions are functions that are easy to compute in one direction but hard to reverse -- a property that is supposed to provide the required secrecy. But this is not 100 per cent tamper proof as powerful computers can break the code.
Now, Ravikanth Pappu and colleagues have developed a physical device that computes a one-way function, encrypting data in an even more secure fashion than its classical counterpart. They use "coherent multiple scattering from inhomogeneous structures" rather than number theory to implement one-way functions. Bureau Report