Software token

Definition
A software token refer to

"the use of secrets stored on a computer and employed in conjunction with an authentication protocol."

Overview
"Software tokens are not as secure as hardware storage tokens, since the secrets used by the software are held in files in a computer on a long-term basis. At best, these secrets typically are protected by a password. Thus, any attack against the computer that compromises these files allows an attacker to retrieve the stored secrets through password-guessing attacks."