Mo. Rev. Stat. § 28.657
Unless otherwise provided by law or contract, the recipient of a digital signature assumes the risk that a digital signature is forged, if reliance on the digital signature is not reasonable under the circumstances. If the recipient determines not to rely on a digital signature pursuant to this section, the recipient shall promptly notify the signer of its determination not to rely on the digital signature.
(L. 1998 S.B. 680 § 20)