Welcome to IEEE Security & Privacy's new department on applied cryptography. Most people think that crypto is beyond the understanding of mere mortals because of the esoteric mathematics that always seem to surround it, but this attitude is dangerous: crypto provides the foundation for any real attempt at security or privacy. Without it, we couldn?t build truly secure solutions for the challenges of information confidentiality and integrity or individual user authentication and authorization; we also wouldn't be able to deal with more complicated concepts such as signing digital documents or enabling nonrepudiation for electronic messages or contracts.