What is htpasswd?
htpasswd is a command-line utility for the open-source Apache HTTP Server that generates password files for HTTP basic authentication.
What are the differences between encryption methods?
MD5:Use MD5 encryption for passwords. On Windows, NetWare, and TPF, this is the default encryption method.
crypt:Use crypt() to encrypt passwords. This is the default on all platforms except Windows, Netware, and TPF. Although it is supported by htpasswd on all platforms, it is not supported by the httpd server on Windows, Netware, and TPF.
SHA:Use SHA encryption for passwords. It is designed for easy transfer or migration to Netscape using the LDAP Directory Interchange Format (ldif).
plain:Uses plaintext passwords without encryption. Although htpasswd can create such passwords on all platforms, the httpd backend only supports plaintext passwords on Windows, Netware, and TPF.
Why make it online?
If we don't use an Apache server—for example, if we use Nginx instead—we might not have this command-line tool available, making it impossible to generate password files. Having an online version makes it convenient for server administrators to use.