**EXHIBIT 31.2**

 

**CERTIFICATION OF PERIODIC REPORT UNDER SECTION 302 OF**

**THE SARBANES-OXLEY ACT OF 2002**

 

I, Peter J. Maloney, certify that: 

 

1.  I have reviewed this annual report on Form 10-K of Keynote Systems, Inc.; 

 

2.  Based on my knowledge, this annual report does not contain any untrue statement of a material fact or omit to state a material factnecessary 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 annualreport, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report; 

 

4.  The registrant’s other certifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15(d)-15(f)) for the registrant and have: 

 

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

 

b)  Designed such internal control over financial reporting, or caused such internal control over financial reporting to bedesigned under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

 

c)  Evaluated the effectiveness ofthe registrant’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 anychange in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal year that has materially affected, or is reasonably likely to materially affect, the registrant’s internalcontrol over financial reporting. 

 

5.  Theregistrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of the registrant’s board of directors:

 

a)  All significant deficienciesand material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

 

b)  Any fraud, whether or notmaterial, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting. 

 

Date:    December 8, 2005