A digital signature is analogous to an ordinary hand-written signature used in signing messages. RSA digital signatures have been adopted by Visa and Mastercard in the secure electronic transactions (SET) standard for providing security of electronic transfers of credit and payment information over the internet. In SET, signatures are used to provide certificates for public keys and to authenticate messages. The authors propose an efficient method of verifying RSA digital signatures. Instead of verifying one signature at a time, it is proposed to batch verify RSA signatures simultaneously. This approach maintains the same computational load as verifying a single signature. Thus, a significant reduction in signature verification time can be achieved.