What are the various ways of securing a web site that could prevent from hacking etc .. ?

  What are the various ways of securing a web site that could prevent from hacking etc .. ?

1) Authentication/Authorization

2) Encryption/Decryption

3) Maintaining web servers outside the corporate firewall. etc.,

Name the validation control available in asp.net?.

RequiredField, RangeValidator,RegularExpression,Custom

validator,compare Validator