Password bcrypt

wp-password-bcrypt is a WordPress plugin to replace WP’s outdated and insecure
MD5-based password hashing with the modern and secure bcrypt.

It is written by roots.io people.

This plugin requires PHP >= 5.5.0 which introduced the built-in
password_hash and
password_verify functions.

See Improving WordPress Password Security
for more background on this plugin and the password hashing issue.