It is often hard to manage different passwords across many accounts: Complicated passwords, including handcrafted ones and those generated by a random password generator, are hard to memorize, but simple passwords are often not safe. A cloud password manager such as LastPass is not a safe option either: cloud password managers often suffer from various security issues. Besides that, it is not cool to expose your passwords to a cloud password manager company. With checksums, the management can be easily done by ourselves, while still maintaining “good” passwords.

Checksums are small-size strings which can be computed from other strings by specific checksum algorithms. Using the most popular checksum algorithms, such as MD5, SHA-1, etc. the checksums usually look very different from the original string, and changing even a single bit of the original string usually leads to very different checksums. For example, the MD5 checksums of the two similar words “bird” and “birds” are completely different (you can use this website to compute the checksum of a string, or use the md5sum or sha1sum command line utility if you are on GNU/Linux or Max OS X):

string MD5 checksum bird 87d28160e9215b17645c734ba7170ba1 birds ea5f5a5293a7d404e091c04939ba2ad8