Authentication of digital medical images with digital signature technology.

PURPOSE: To determine whether digital signature technology (DST) can authenticate digital medical images to the same level of authenticity required for interbank electronic transfer of funds. MATERIALS AND METHODS: Message digests were computed for two magnetic resonance images that differed only by the value of a single bit. RSA (Rivest, Shamir, and Adleman) public key cryptography was used to encrypt each message digest to form a digital signature for each image, a process analogous to the established use of RSA DST for electronic funds transfer. The process was then reversed to authenticate the original image from its digital signature. RESULTS: Although the images differed by less than 0.000095%, their message digests differed at 94% of their characters. The digital signature of the original image proved that it was authentic and that the altered image was not authentic. CONCLUSION: RSA DST can establish the authenticity of images to at least the level of confidence required for interbank electronic transfer of funds.