Notwithstanding Section 16404, the Department of Corrections may withdraw funds for confidential use in an amount not to exceed ten thousand dollars ($10,000) per fiscal year. The sums so withdrawn may be used as a revolving fund where cash advances are necessary. At the close of each fiscal year, the department shall account for and substantiate to the Controller the amount of moneys so withdrawn during that fiscal year with vouchers and itemized statements, exclusive of names and locations, along with a certificate of the purpose and necessity for secrecy. The Controller is authorized to perform audits of these vouchers and itemized statements as may be necessary.