gistfile1.js

//atmosphere packages: jparker:crypto-aes , matb33:collection-hooks

var encryptionKey = "adsffe534tryertrrtweGe";

//Before insert Hooks, I decide to use it only in the server. If you use on the client and server, you're encrypting it twice.
Todos.before.insert( function( userId , doc ){
  
  doc.text = CryptoJS.AES.encrypt( doc.text , encryptionKey ).toString();
  
} );

Todos.before.update(function (userId, doc, fieldNames, modifier, options) {
  
  if( modifier.$set && modifier.$set.text ){
    
    modifier.$set.text = 
      CryptoJS.AES.encrypt( modifier.$set.text , encryptionKey )
      .toString();
      
  }

});

//Publishing and decrypting
Meteor.publish('todos', function(listId) {
  check( listId , String );

  var cursor = Todos.find( { listId : listId } ),
      self = this;

  var handle = cursor.observeChanges({
      added : function( id , fields ){

          fields.text = CryptoJS.AES
                          .decrypt( fields.text , encryptionKey )
                          .toString( CryptoJS.enc.Utf8 );

          self.added( 'todos' , id , fields );
      },

      changed :  function( id, fields ){

          if( fields.text ){
            fields.text = CryptoJS.AES
                            .decrypt( fields.text, encryptionKey )
                            .toString( CryptoJS.enc.Utf8);

          }

          self.changed('todos', id, fields);
      },

      removed : function( id ){
        self.removed( 'todos' , id );
      }

  });

  self.onStop( function () {
            handle.stop();
        } );

  self.ready();
  
});