htpasswd is a command tool of the open source http server apache httpd, which is used to generate the password file for http basic authentication.
MD5: Use MD5 to encrypt the password. On Windows, Netware and TPF, this is the default encryption method.
crypt: Use crypt() to encrypt the password. On platforms other than Windows, Netware and TPF, this is the default. While it is supported by htpasswd on all platforms, it is not supported by the httpd server on Windows, Netware and TPF.
SHA: Use SHA to encrypt passwords. It is designed to facilitate porting or porting to Netscape using the LDAP Directory Interchange Format (ldif).
plain: no encryption, use plain text password. While htpasswd can create such passwords on all platforms, the httpd backend only supports plain text passwords on Windows, Netware and TPF.
If we do not use an apache server, such as nginx, etc., we may not have this command-line tool at hand, and the password file cannot be generated. The online version is convenient for server administrators to use.