Radiology, Vol 194, 771-774, Copyright © 1995 by Radiological Society of North America
Authentication of digital medical images with digital signature technology
JP Smith
First Hill Diagnostic Imaging, Seattle, WA 98104.
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.
