My favorite trick is the XOR one time pad. XOR anything (text, images, etc) with a random pad or "key" the same length as the data your are encrypting... and y

My favorite trick is the XOR one time pad. XOR anything (text, images, etc) with a random pad or "key" the same length as the data your are encrypting... and you've got an completely unbreakable cipher. Just be careful as with any one-time-pad cipher. The key needs to be the same length as the data, generated randomly, and you can only use it once... no key reuse ever.