From Wikipedia, the free encyclopedia:

Cryptography is the field concerned with linguistic and mathematical techniques for securing information, particularly in communications. Historically, cryptography was concerned solely with encryption; that is, means of converting information from its normal, comprehensible form into an incomprehensible format, rendering it unreadable without secret knowledge. Encryption was used primarily to ensure secrecy in important communications, such as those of spies, military leaders, and diplomats. In recent decades, however, the field of cryptography has expanded its remit: modern cryptography provides mechanisms for more than just keeping secrets and has a variety of applications including, for example, authentication, digital signatures, electronic voting and digital cash. Moreover, people without extraordinary needs for secrecy use cryptographic technology, which is often built transparently into much of computing and telecommunications infrastructure.
