<PAGE>


                                                                    EXHIBIT 31.1

             RULE 13A-14(A) CERTIFICATION OF CHIEF EXECUTIVE OFFICER

I, Richard J. Lampen, certify that:

1. I have reviewed this quarterly report on Form 10-QSB of CDSI Holdings 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. Based on my knowledge, the financial statements, and other financial
information included in this report, fairly present in all material respects the
financial condition, results of operations and cash flows of the small business
issuer as of, and for, the periods presented in this report;

4. The small business issuer's other certifying officer and I are responsible
for establishing and maintaining disclosure controls and procedures (as defined
in Exchange Act Rules 13a-15(e) and 15d-15(e) for the small business issuer and
have:

      (a) designed such disclosure controls and procedures, or caused such
disclosure controls and procedures to be designed under our supervision, to
ensure that material information relating to the small business issuer,
including its consolidated subsidiaries, is made known to us by others within
those entities, particularly during the period in which this report is being
prepared;

      (b) [intentionally omitted];

      (c) evaluated the effectiveness of the small business issuer's disclosure
controls and procedures and presented in this report our conclusions about the
effectiveness of the disclosure controls and procedures, as of the end of the
period covered by this report based on such evaluation; and

      (d) disclosed in this report any change in the small business issuer's
internal control over financial reporting that occurred during the small
business issuer's most recent fiscal quarter (the small business issuer's fourth
fiscal quarter in the case of an annual report) that has materially affected, or
is reasonably likely to materially affect, the small business issuer's internal
control over financial reporting; and

5. The small business issuer's other certifying officer and I have disclosed,
based on our most recent evaluation of internal control over financial
reporting, to the small business issuer's auditors and the audit committee of
the small business issuer's board of directors (or persons performing the
equivalent functions):

      (a) all significant deficiencies and material weaknesses in the design or
operation of internal control over financial reporting which are reasonably
likely to adversely affect the small business issuer's ability to record,
process, summarize and report financial information; and

      (b) any fraud, whether or not material, that involves management or other
employees who have a significant role in the small business issuer's internal
control over financial reporting.

Date: April 30, 2004


                                            /s/ Richard J. Lampen
                                            ------------------------------------
                                            Richard J. Lampen
                                            Chairman and Chief Executive Officer