What is htpasswd?
htpasswd is a command-line tool for the open-source HTTP server Apache HTTP Server, used to generate password files for HTTP basic authentication.
What are the differences between encryption methods?
MD5:Encrypts passwords using MD5. This is the default encryption on Windows, Netware, and TPF.
crypt:Encrypts passwords using crypt(). This is the default on all platforms except Windows, Netware, and TPF. Although it is supported by htpasswd on all platforms, the httpd server does not support it on Windows, Netware, and TPF.
SHA:Encrypts passwords using SHA. It is designed for ease of transition or porting to Netscape using LDAP Directory Interchange Format (ldif).
plain:Does not encrypt, uses plain text passwords. Although htpasswd can create such passwords on all platforms, the httpd backend only supports plain text passwords on Windows, Netware, and TPF.
Why make it online?
If we do not use the Apache server, such as using nginx, etc., we may not have this command-line tool at hand and cannot generate a password file. Having an online version can be convenient for server administrators.