Neb. Rev. Stat. §§ 32-318
Any registered voter whose signature does not appear in the registration records, due to fading, damage, loss, or other circumstance that affects the appearance or presence of the signature, may be required to submit his or her signature on a form prescribed by the Secretary of State to be included with the registration records of the registered voter. If the election commissioner or county clerk determines at any time that a then current signature of any registered voter is needed or if a registered voter's signature becomes subject to verification and a similar signature is not on file for such voter, the election commissioner or county clerk may request that the registered voter submit his or her signature on a form prescribed by the Secretary of State to be included with the voter's registration records.
Neb. Rev. Stat. §§ 32-318