Unambiguous, free and informed consent

Definition
Unambiguous, free and informed consent is

"[c]onsent [that] is understood:


 * to have been freely given. In other words, the data subject was not pressurised to say "yes";
 * to be specific, meaning that the consent relates to a well-defined processing operation;
 * to be informed. The data subject has received all useful information about the planned processing.

It is not necessary for consent to be given in writing, but oral consent can create problems with the burden of proof."