and died of leukemia three years later, and he didn’t live to see the profound changes wrought by the Internet and the Web. Beyond a limited circle of information specialists, textile makers, and historians, his name is largely forgotten. But Luhn’s ideas endure. Today, hashing plays a host of roles in managing and protecting our digital lives. When you enter your password on a website, the server is likely storing a hashed version of your password. When you interact with a website using a secure connection (where the URL begins with “https”) or purchase something with Bitcoin, hashes are at work there, too. For cloud services like Dropbox and Google Drive, hashing makes storing and sharing files far more efficient. In genetics and other data-intensive research, hashing sharply reduces the time needed to computationally sift through vast quantities of data.