I am not chess.com staff, however if I access my chess.com email my password is included in the URL as plain text which means it must either not be encrypted or encrypted in some form that allows it to be decrypted. This is potentially insecure.
Passwords should be stored in a form that cannot be decrypted, as decryption is not necessary to verify the password. What should usually happen is the user enters their password, it is encrypted (or hashed) using a one-way algorithm and this result is compared to what is stored in the database. When the user originally chose their password the same one-way algorithm would be used to encrypt the password and store it.
If you've seen the news today, you may know that Yahoo.com is getting beaten up for poor security practices that led to almost half a million user passwords being posted online. One of the basic mistakes that Yahoo apparently made was to store passwords in plain-text form in an internal database.
When I signed up for my chess.com account, the site sent me the password that I entered back to me as plain text in an email. That makes me think that maybe chess.com handles passwords in a generally unsecure manner.
Can someone from chess.com comment on this security issue?