What is htpasswd?
htpasswd is a command tool of the open source http server apache httpd, which is used to generate password files for basic http authentication.
What is the difference between encryption methods?
MD5:Use MD5 to encrypt the password. On Windows, Netware, and TPF, this is the default encryption.
crypt:Use crypt() to encrypt the password. On platforms other than Windows, Netware and TPF, this is the default. While it can be supported by htpasswd on all platforms, However, it is not supported by httpd servers on Windows, Netware and TPF.
SHA:Use SHA to encrypt the password. It is intended to facilitate the transfer or porting to the Interchange Format using the LDAP Directory (LDIF) designed for Netscape.
plain:No encryption, use plain text passwords. Although htpasswd can establish such a password on all platforms, the httpd backend is only Windows, Plain text passwords are supported on Netware and TPF.
Why make it online?
If we do not use apache server, for example, nginx, etc., we may not have this command line tool on hand, so we cannot generate password files. With the online version, it is convenient for server administrators to use.