A method enables a recipient of JPEG image data to authenticate the JPEG image data by producing a hashing function from a first section of the JPEG image data. A first integrity checking value is produced from the hashing function produced from the first section of JPEG image data and, from a least significant transmitted bit-plane of a second section of the JPEG image data, an embedded encrypted signature string is extracted and decrypted to generate a second integrity checking value. The first and second integrity checking values are compared and the first section of the JPEG image data is authenticated when the second integrity checking value matches the first integrity checking value.