One way to check if a value has changed from its original state (server side), is through HMAC mechanism.

Basically it generates a hash based on a string and secret key, and this hash is sent along with the form as a hidden field (http get), if the value is changed by the customer then the recalculation of the hash (http post) will be different from what is stored in the hidden field, then you know that someone change the value of that field.

This may be a little overworked but is one of the safest methods.

https://security.stackexchange.com/questions/20129/how-when-do-i-use-hmac

How to generate HMAC-SHA1 in C#?

One way to check if a value has changed from its original state (server side), is through HMAC mechanism.

Basically it generates a hash based on a string and secret key, and this hash is sent along with the form as a hidden field (http get), if the value is changed by the customer then the recalculation of the hash (http post) will be different from what is stored in the hidden field, then you know that someone change the value of that field.

This may be a little overworked but is one of the safest methods.

https://security.stackexchange.com/questions/20129/how-when-do-i-use-hmac

How to generate HMAC-SHA1 in C#?

One way to check if a value has changed from its original state (server side), is through HMAC mechanism.

Basically it generates a hash based on a string and secret key, and this hash is sent along with the form as a hidden field (http get), if the value is changed by the customer then the recalculation of the hash (http post) will be different from what is stored in the hidden field, then you know that someone change the value of that field.

This may be a little overworked but is one of the safest methods.

http://security.stackexchange.com/questions/20129/how-when-do-i-use-hmac

How to generate HMAC-SHA1 in C#?

One way to check if a value has changed from its original state (server side), is through HMAC mechanism.

Basically it generates a hash based on a string and secret key, and this hash is sent along with the form as a hidden field (http get), if the value is changed by the customer then the recalculation of the hash (http post) will be different from what is stored in the hidden field, then you know that someone change the value of that field.

This may be a little overworked but is one of the safest methods.

https://security.stackexchange.com/questions/20129/how-when-do-i-use-hmac

How to generate HMAC-SHA1 in C#?