1. A method of encoding content data into a digital image comprising: determining bit values of a pixel within the digital image; modifying the bit values within the pixel based on content data to be encoded in order to encode the content data into the digital image; wherein determining the bit values of a pixel within the digital image comprises determining a binary representation of the bit values of the pixel and wherein modifying the bit values comprises determining a binary representation of the content data to be encoded within the pixel and encoding the content data using a reversible binary operation.