Exhibit 31.3
CERTIFICATION
PURSUANT TO RULES 13a-14(a) AND 15d-14(a)
UNDER
THE SECURITIES EXCHANGE ACT OF 1934, AS ADOPTED PURSUANT TO
SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002
I, Edmund Nabrotzky, certify that:
| 1. | I have reviewed this Amendment No. 1 to Quarterly Report on Form 10-Q for the quarter ended June 30, 2026 of CID Holdco, Inc.; |
| 2. | Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report; |
| 3. | [Omitted]; |
| 4. | [Omitted]; |
| 5. | [Omitted]. |
Date: October 2, 2026
| /s/ Edmund Nabrotzky | |
| Edmund Nabrotzky | |
| Chief Executive Officer | |
| (Principal Executive Officer) |