<PAGE>

                                                                    EXHIBIT 99.5

ADVANCED INSTRUCTION TO SELL COMMON STOCK

To: Deutsche Bank Alex. Brown
    A Division of Deutsche Bank Securities Inc.

Account Number: ____________

         I am a holder of shares and options to acquire shares, of the common
stock RSA Security, Inc. (Tkr: RSAS). I would like to periodically sell Company
shares in order to diversify my portfolio. I also wish to take advantage of Rule
10b5-1 under the Securities Exchange Act of 1934, as amended, which provides for
an affirmative defense from insider trading liability for purchases and sales
effected pursuant to a contract, instruction or plan entered into when a person
is not aware of any material nonpublic information. This instruction
("Instruction") is intended to constitute a "written plan for trading
securities" within the meaning of Rule 10b5-1.

         I hereby instruct Deutsche Bank Securities Inc. (referred to herein as
"Deutsche Bank Alex. Brown") to sell currently held shares of Common Stock,
pursuant to the specific instructions set forth in the attached memo. My orders
here under are given to you on a not held basis, meaning that you shall use your
best judgement in the execution of each order, and that you shall be relieved of
all responsibility with respect to the time of execution or the price or prices
of execution. I understand that in exercising such judgement, it is possible
that you may not sell some or all of the shares that you are authorized
hereunder to sell in any given period under this Instruction.

         You are authorized to make deliveries of securities and payment of
moneys in accordance with your normal practice. All shares to be sold shall have
been previously deposited into my account, and you shall not be required to
follow this Instruction if shares are not present in my account (or acceptable
arrangements to deliver option shares have not been made) prior to the dates on
which sales shall occur. If this Instruction requires you to exercise stock
options you shall do so in accordance with your normal procedures, and unless
instructed otherwise, remit the exercise price and the withholding tax as
calculated by the Company. In no instance should you exercise options that are
not in the money. The share amount listed above shall be increased or decreased
to reflect stock splits should they occur. I understand that I shall be
responsible to arrange for any filings that may be required under applicable law
(e.g., Form 144, Schedule 13D, and Forms 4 and 5), and that I may be subject to
the short swing profit rules contained in Section 16 of the Securities Exchange
Act of 1934. In this connection, I understand that upon my request, you will
assist me in making advance arrangements regarding the filing of Forms 144;
provided that you agree to notify me and a designated representative of RSA's
legal department within eight hours of making any trade so that I may file the
required Form 4 in a timely fashion:

         -        Margaret Seif: Phone: (781) 515-5403; email:
                  mseif@rsasecurity.com

         -        Kathryn Leach: Phone: (781) 515-5422; email:
                  kleach@rsasecurity.com

         -        Chris Dollase: Phone: (781) 515-5507; email:
                  cdollase@rsasecurity.com

         All sales shall be effected in your normal fashion in accordance with
your terms and conditions for my account and risk. You may act as principal in
any transaction hereunder. I understand that you may not be able to make all of
the sales contemplated under this Instruction due to a market disruption or a
legal, regulatory or contractual restriction applicable to you or any other
event or circumstance. I further understand that even in the absence of such a
circumstance, you may be unable to make sales consistent with ordinary
principles of best execution due to insufficient volume of trading or other
market factors in effect on the date of a sale. I hereby ratify and confirm any
and all transactions with you in accordance with this Instruction. I also agree
to indemnify and hold Deutsche Bank Alex. Brown harmless from any and all losses
arising from any cause of action arising from its performance of this
Instruction. For purposes of this Section, the term "losses" shall mean monetary
damages for which a court or regulatory agency has found Deutsche Bank to be
finally liable, after all appeals have been exhausted, but which shall in no
event exceed an amount equal to the proceeds received by me in connection with
exercises of stock options pursuant to this Instruction. Notwithstanding the
foregoing, "losses" shall not include Deutsche Bank's attorneys fees, and
Deutsche Bank may not settle any action for which it will claim indemnification
from me without my prior written consent.

         You will cease making sales under this Instruction as soon as
practicable following receipt of written notice from the Company, confirmed by
telephone, that the Company has entered into a transaction that results in

<PAGE>

my being subject to trading restrictions. You shall resume making sales in
accordance with this Instruction as soon as practicable after you receive
written notice from the Company of the cessation or termination of any such
trading restriction. Any sales not made as a result of the imposition of any
trading restriction shall be deemed to be cancelled and shall not be made
pursuant to this Instruction.

         While this Instruction is in effect I will not enter into or alter any
corresponding or hedging transaction or position with respect to the Common
Stock (including any securities convertible or exchangeable into Common Stock).
I agree that until this Instruction has been terminated I will not enter into a
binding contract with respect to the purchase or sale of Common Stock with
another broker, dealer or financial institution, instruct any broker, dealer or
financial institution to purchase or sell Common Stock or adopt a trading plan
with respect to Common Stock other than this Instruction.

         I represent and warrant that I am not presently aware of any material
nonpublic information regarding the Company or its securities and that I am
currently able to sell Common Stock under the Company's insider trading policies
and covenant that I will not discuss or otherwise disclose material nonpublic
information to my investment representative or any other of your personnel
responsible for carrying out this Instruction. I have obtained the approval of
the Company's counsel to enter into this Instruction.

         This Instruction may be modified, terminated or amended only by a
writing signed by the parties hereto. Any modification or amendment of this
Instruction may only occur at a time when I am not aware of material nonpublic
information concerning the Company or its securities and I am otherwise
permitted to make sales under the Company's insider trading policies. If this
Instruction is modified or amended, or if I establish a new plan after
termination of this Instruction, no sales shall be made during the thirty (30)
calendar days immediately following such modification, amendment or termination
(other than sales already provided for in the Instruction prior to modification,
amendment or termination).

         This Instruction shall not be effective until Deutsche Bank Alex. Brown
confirms its acceptance in writing by signing below. It shall remain in full
force and effect until revoked or modified by me in writing. Deutsche Bank Alex.
Brown may decline to act hereunder upon reasonable notice. I hereby irrevocably
authorize you to accept any instruction from the Company to cease or suspend
sales hereunder.

/s/Jeffrey Glidden                                          12/4/03
----------------------                                      -------
Jeffrey Glidden                                             Date

--------------------------------------------------------------------------------
Accepted
Deutsche Bank Alex. Brown

/s/Stuart C. Williams
--------------------------------------
Stuart C. Williams, Branch Manager

Dated: 12/5/03

<PAGE>

SCHEDULE A TO ADVANCED INSTRUCTION TO SELL COMMON STOCK

To: Deutsche Bank Alex. Brown
    A Division of Deutsche Bank Securities Inc.

Account Number: ____________- Jeffery Glidden

The instructions outlined below are to be used as my 10B5-1 Plan for RSA
Security, Inc.

This plan shall commence on February 10, 2004, the day the first order is
placed, and expire on December 2, 2004, the day the last order expires, unless
extended in writing 60 days prior to expiration.

In total, the directions and orders below allow for the sale of up to a total of
160,000 shares of RSA Security, Inc. stock for the duration of this plan as
stated above.

Any partial execution of the limit orders below will result ion the balance of
that order being placed in the next open window period. I understand that DB
Alex. Brown is a market maker in RSAS and that the limits below are net of
commission.

QUARTER 1 2004

         Order 1 - sell 30,000 shares at $12.00 net per share or better; enter
         order on February 10, 2004 as a good order through March 2, 2004

         Order 2 - sell 10,000 shares at $13.00 net per share or better; enter
         order on February 10, 2004 as a good order through March 2, 2004

QUARTER 2 2004

         Order 3 - sell 30,000 shares at $12.00 net per share or better; enter
         order on May 4, 2004 as a good order through June 1, 2004

         Order 4 - sell 10,000 shares at $13.00 net per share or better; enter
         order on May 4, 2004 as a good order through June 1, 2004

QUARTER 3 2004

         Order 5 - sell 30,000 shares at $12.00 net per share or better; enter
         order on August 4, 2004 as a good order through September 1, 2004

         Order 6 - sell 10,000 shares at $13.00 net per share or better; enter
         order on August 4, 2004 as a good order through September 1, 2004

QUARTER 4 2004

         Order 7 - sell 30,000 shares at $12.00 net per share or better; enter
         order on November 2, 2004 as a good order through December 2, 2004

         Order 8 - sell 10,000 shares at $13.00 net per share or better; enter
         order on November 2, 2004 as a good order through December 2, 2004

Sincerely,

/s/Jeffrey Glidden                                                   12/4/03
----------------------------                                         ---------
Jeffrey Glidden                                                      Date