How to protect view state from tampering when it's passed over an unencrypted channel ?

103.

In Page directive set EnableViewStateMac="true"

In Register directive set EnableViewStateMac="true"

In web config set Protectviewstate="true"

In IIS set Viewstate protection

Set the EnableViewStateMac property to true when a high degree of data integrity is required between postbacks, or where there is a high risk of tampering