The Google Search Appliance must support DoD requirements to enforce password complexity by the number of lower case characters used.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determine how long it takes to crack a password.
The more complex the password is, the greater the number of possible combinations that need to be tested before the password is compromised.
Use of a complex password helps to increase the time and resources required to compromise the password.