Create a hidden character field? How can I create a hidden character field in D7 for a text field that hides the user input like the password field does? For example a field called "social security number" should not display the users input in plain text, but instead hide the input. Is there a module that can do this? Or how would that be realized?
You can with '#type' =&gt; 'password' in  your form.

Ex:

$form['social_sec'] = array(
  '#type' =&gt; 'password',
  '#title' =&gt; t('Social Security'),
  '#description' =&gt; t('Please enter your social security number'),
  '#size' =&gt; 9,
  '#maxlength' =&gt; 9,
  '#required' =&gt; TRUE,
);


If you want this as a field in a node's form, then you will have to use hook_form_BASE_FORM_ID_alter and alter an already existing field.