California Code, Elections Code - ELEC § 2202

(a) The county elections official shall preserve all uncanceled affidavits of registration in a secure manner that will protect the confidentiality of the voter information consistent with Section 2194.

The affidavits of registration shall constitute the register required to be kept by Article 5 (commencing with Section 2183) of Chapter 2.

(b) In lieu of maintaining uncanceled affidavits of registration, the county elections official may microfilm, record on optical disc, or record on any other electronic medium that does not permit additions, deletions, or changes to the original document, the uncanceled affidavits of registration. Any such use of an electronic medium to record uncanceled affidavits shall protect the security and confidentiality of the voter information. The county elections official may dispose of any uncanceled affidavits of registration transferred pursuant to this section. The disposal of any uncanceled affidavits shall be performed in a manner that does not compromise the security or confidentiality of the voter information contained therein.For purposes of this section, a duplicate copy of an affidavit of registration shall be deemed an original.The Secretary of State may adopt appropriate regulations for the purpose of this section.