EXHIBIT 4.1

      THIS NOTE HAS NOT BEEN  REGISTERED  UNDER THE  SECURITIES  ACT OF 1933, AS
AMENDED  (THE "1933  ACT"),  OR UNDER THE  PROVISIONS  OF ANY  APPLICABLE  STATE
SECURITIES  LAWS,  BUT HAS BEEN  ACQUIRED BY THE  REGISTERED  HOLDER  HEREOF FOR
PURPOSES OF INVESTMENT  AND IN RELIANCE ON STATUTORY  EXEMPTIONS  UNDER THE 1933
ACT, AND UNDER ANY APPLICABLE  STATE SECURITIES LAWS. THIS NOTE MAY NOT BE SOLD,
PLEDGED,  TRANSFERRED OR ASSIGNED EXCEPT IN A TRANSACTION  WHICH IS EXEMPT UNDER
PROVISIONS OF THE 1933 ACT AND ANY APPLICABLE  STATE SECURITIES LAWS OR PURSUANT
TO AN EFFECTIVE REGISTRATION STATEMENT; AND IN THE CASE OF AN EXEMPTION, ONLY IF
THE COMPANIES HAVE RECEIVED AN OPINION OF COUNSEL  SATISFACTORY TO THE COMPANIES
THAT SUCH TRANSACTION DOES NOT REQUIRE REGISTRATION OF THIS NOTE.

                        DIGITAL DESCRIPTOR SERVICES, INC.


February 25, 2005                                           Sea Girt, New Jersey

$3,500,000.00, Subject to Increase Adjustment

                    2.86% SECURED CONVERTIBLE PROMISSORY NOTE

      1.    Digital Descriptor Systems, Inc., a Delaware corporation (the
"Parent") and CGM Applied Security  Technologies,  Inc., a Delaware  corporation
("Acquisition  Sub", and together with the Parent,  the "Companies"),  for value
received,  hereby  promise  to  pay,  jointly  and  severally,  to CGM  Security
Solutions,  Inc., or registered  assigns (the  "Holder") on the payment date set
forth below, at the principal offices of the Parent,  the principal sum of Three
Million Five Hundred Thousand  Dollars  ($3,500,000)  (the "Principal  Amount"),
subject to increase  pursuant  to the terms  contained  herein,  in such coin or
currency  of the United  States of  America  as at the time of payment  shall be
legal tender for the payment of public and private debts, and to pay interest on
the  outstanding  principal  sum  hereof  at the rate of 2.86%  per  annum  (the
"Note");  provided,  however,  that the Principal  Amount shall be subject to an
automatic  increase to the "New Principal  Amount",  defined below, in an amount
equal to the average of the two amounts  determined in accordance with Valuation
Procedure One and Valuation  Procedure Two (each defined below, and together the
"Procedures")  if any, and applied in accordance with the conditions  below. Any
increase in the Principal Amount and the commencement of accrual of any interest
thereon  shall be  effective  as of the date on which the results of the last of
the Procedures are received by the parties (the "Effective Date").

      2.    Pursuant to "Valuation  Procedure  One": (a) within 60 days of
December 31, 2007,  the Parent's then  independent  auditor shall  determine the
gross revenues  generated by Acquisition Sub for the fiscal year ending December
31,  2007  in  accordance  with  generally   accepted   accounting   principles,
consistently  applied  (the  "Gross  Revenue"),  and shall  certify  same to the
parties;  (b) the  Gross  Revenue  shall be  multiplied  by a  factor  of 1.0 to
determine the new value of  Acquisition  Sub (the "New CGM Value One");  and (c)
the amount of any increase in the Principal  Amount  pursuant to this  Valuation
Procedure  One shall be equal to the New CGM Value  One,  less  $5,000,000,  and
shall be referred to as the "Procedure One Principal Amount


<PAGE>


Increase". In the event that the application of Valuation Procedure One does not
result in a Procedure One Principal Amount  Increase,  then under this Valuation
Procedure One the  Principal  Amount shall be deemed the Procedure One Principal
Amount Increase for all purposes under this Valuation Procedure One.

      3.    Pursuant to "Valuation Procedure Two", an independent  investment
bank,  qualified to undertake  valuations of public  companies  (the  "Valuation
Expert"),  mutually agreed upon by the Parent and the former shareholders of the
Holder, as of the date hereof, shall establish the value of Acquisition Sub (the
"New CGM Value Two"),  in  accordance  with the  following  procedures:  (a) the
parties shall agree upon the Valuation Expert in writing,  no later than October
30,  2007,  and if not so agreed by such date,  the  Valuation  Expert  shall be
selected by the  American  Arbitration  Association,  whose  selection  shall be
binding upon the  parties;  (b) the  Valuation  Expert  shall be  authorized  to
deliver its valuation of Acquisition  Sub no later than March 31, 2008,  subject
to reasonable extensions in the discretion of the Valuation Expert, and; (c) the
amount of any  automatic  increase  in the  Principal  Amount  pursuant  to this
Valuation Procedure Two shall be equal to the New CGM Value Two, less $5,000,000
and shall be referred to as the "Procedure Two Principal  Amount  Increase".  In
the event that the  application of Valuation  Procedure Two does not result in a
Procedure Two Principal Amount Increase, then under this Valuation Procedure Two
the Principal Amount shall be deemed the Procedure Two Principal Amount Increase
for all purposes under this Valuation Procedure Two.

      4.    The Holder and the Companies  agree that when  determining  the New
CGM Value Two in Valuation  Procedure Two, the Valuation Expert,  when preparing
its valuation,  shall: (i) when required to utilize financial  statements in its
valuation, rely solely upon the consolidated audited financial statements of the
Parent and  Acquisition  Sub for the fiscal  years ended  December  31, 2007 and
2006, excluding from its valuation any and all financial information that may be
included  therein and  attributable to any other  subsidiary or affiliate of the
Parent (the "Financial Statements");  (ii) exclude extraordinary expenses as may
have been  allocated  or  charged  by the  Parent,  or any other  subsidiary  or
affiliate of Parent, to Acquisition Sub, retaining, however, for purposes of the
valuation any reasonable  fees charged  solely by Parent to Acquisition  Sub and
which  represent  any payments to the  Parent's  management  and which  directly
correspond  to  any   improvements   in  the   Acquisition   Sub's   operational
effectiveness  as  determined  by  the  Valuation  Expert,  in  accordance  with
generally  accepted  accounting  principles,  consistently  applied;  and  (iii)
exclude  any  debt  on  the  Financial  Statements  owed  to the  Parent,  other
subsidiaries  and affiliates or to the persons or entities set forth on Schedule
A.

      5.    Notwithstanding  the  foregoing,  if the gross  sales of CGM
Security  Solutions,  Inc. for the one year period ended  December 31, 2004,  as
included in the final  certified  audited  financial  statements for such period
("Actual Gross Sales") do not equal at least  $4,030,000  (the "Target  Sales"),
the  principal  amount of this Note shall be  reduced by an amount  equal to the
difference  between the Target Sales and the Actual  Gross Sales (the  "Adjusted
Note Principal Amount Reduction").

      6.    Upon  the  Effective  Date,  the  Principal  Amount  of  this  Note
of $3,500,000 shall  automatically  be: (i) increased by the amount equal to the
average of the  Procedure One  Principal  Amount  Increase and the Procedure Two
Principal  Amount  Increase,  and; (ii) decreased by the Adjusted Note Principal
Amount Reduction, if any, and if any increase in the $3,500,000 principal


                                       3
<PAGE>


amount of this Note results  therefrom,  such increase,  added together with the
original  principal  of  $3,500,000  shall be deemed for all  purposes  the "New
Principal  Amount" of this Note.  The  parties  agree that  notwithstanding  any
result of the  foregoing  calculations,  the New  Principal  Amount of this Note
shall not be less than the Principal Amount.

      7.    Accrued interest shall be payable upon the outstanding Principal
Amount  of  this  Note  on the  30th  day  following  each  of the  first  three
anniversaries  of this Note.  The  balance of any  accrued  interest  on the New
Principal  Amount,  if any, shall be due and payable 30 days after the Effective
Date.  The New Principal  Amount of this Note, as determined in accordance  with
the terms hereof and subject to the cash payment  limitation of Section 9 below,
together with unpaid accrued interest shall be payable on the 30th day following
the Effective  Date (the "Payment  Date") in like coin or currency to the Holder
hereof at the office of the Parent as hereinafter  set forth,  provided that any
payment otherwise due on a Saturday, Sunday or legal Bank holiday may be paid on
the following business day.

      8.    In the event that the Parent or Acquisition  Sub determine that for
any reason  whatsoever  any interest or other  consideration  payable  under the
terms of this Note are in violation of any applicable usury statute of the State
of New Jersey, Parent and/or Acquisition Sub shall, prior to the due date of the
New Principal Amount:  (i) provide Holder with written notice of such violation,
setting  forth the facts and  circumstances  supporting  such claims,  and; (ii)
include with such written notice, a legal opinion, addressed to the Holder, from
an attorney  admitted to  practice  in the State of New  Jersey,  containing  an
unqualified  legal opinion that under the facts and  documents  delivered by the
Parent and/or the  Acquisition  Sub that the payments due under this Note are in
violation  of one or more usury  statutes of the State of New Jersey (the "Usury
Notice").  Within 30 days' of the sending of the Usury Notice, the Parent and/or
Acquisition Sub shall institute an action seeking a declaratory  judgment in the
Superior Court, County of Somerset, State of New Jersey (the "Court"), to obtain
a judgment  (1) on the  application  of the New  Jersey  usury  statutes  to the
payments  due under  this Note,  and to obtain a ruling as to (2) the  aggregate
maximum rate of interest  payments  that could be legally  charged to Parent and
Acquisition  Sub on the  Principal  Amount under  applicable  statutes,  for the
period commencing from the date hereof through the due date of the New Principal
Amount (the "Maximum Legal Amount"). Parent and Acquisition Sub acknowledge that
they have set forth below their respective  representations,  which include that
they have performed their legal due diligence in connection with their execution
and  delivery  of this  Note and that to their  best  knowledge,  the  terms and
payments due under this Note are not in  violation  of any usury  statute of the
State of New Jersey, and that the Holder is relying upon such representations to
accept delivery of this Note,  execute and deliver the Asset Purchase  Agreement
and other documents,  all dated the date hereof and pursuant to which the Holder
is selling his entire business to the Parent and  Acquisition  Sub, and that any
subsequent sending of the Usury Notice and subsequent court action by the Parent
and/or the  Acquisition  Sub that results in the Court  concluding  that all the
payments due and payable under this Note are not in violation of any  applicable
New  Jersey  usury  statute,   would  represent  breaches  of  their  respective
representations  set forth  herein  and would  result in  serious  injury to the
Holder, entitling the Holder to liquidated damages.


                                       3
<PAGE>


Accordingly,  in the event the Usury  Notice is sent by the  Parent  and/or  the
Acquisition  Sub prior to the  payment of all sums due under this Note,  and the
Court in the declaratory judgment action, determines that the aggregate payments
due under this Note are not in violation of any New Jersey  usury  statute,  the
Parent and Acquisition Sub, jointly and severally,  shall pay to the Holder,  on
demand,  in addition to the payments due under this Note,  (A) an additional sum
equal to the difference  between the aggregate and lawful amounts due under this
Note as  determined  by the Court and the  Maximum  Legal  Amount and (B) all of
Holder's legal fees,  administrative  costs and expenses incurred by Holder as a
result of Holder's  participation  in the declaratory  judgment  action.  In the
event the Court finds that any amounts due under this Note to be usurious  under
the laws of the State of New Jersey, then so much of such interest payable under
the terms of this Note as shall be deemed to be  usurious  shall be  deducted by
the Court from the payments  due under this Note and the Parent and  Acquisition
Sub shall forthwith and immediately pay the reduced legally  permissible  amount
of principal and interest due under this Note to the Holder,  no later than five
(5) days following such Court decision.

      9.    Notwithstanding  the  foregoing,  on the Payment Date,  subject to
the  limitations  set forth  below,  the  Companies  shall either (i) pay to the
Holder the New Principal  Amount  together with any remaining  accrued  interest
thereon,  in cash,  not to  exceed  $6,000,000  (the  "Cash  Payment"),  and the
balance,  if any, shall be paid in Parent stock as more  specifically  described
below (the  "Stock  Payment"),  or (ii)  provided  that there is no  outstanding
default under the "Debt Instruments"  identified in Exhibit G to a certain Asset
Purchase  Agreement  between  the parties to this Note and dated the date hereof
(an "NIR Default",  in which case such the "Asset  Transfer" option shall not be
available to the Companies), transfer all of Acquisition Sub's assets, including
the  "Assets" as  identified  in the Asset  Purchase  Agreement,  dated the date
hereof,  among the Companies and the Holder (the "Asset  Transfer"),  as well as
the corporate  name and  trademarks,  back to the Holder,  its  shareholders  or
assigns  (as  designated  by the  Holder),  free and clear of any and all liens,
security interests or claims of any nature  whatsoever,  and unencumbered by any
debts  associated  with the  Asset  Transfer.  Costs  associated  with the Asset
Transfer shall be borne by the Companies.  The  indebtedness  under this Note is
secured by a certain  Security  Agreement  and  Intellectual  Property  Security
Agreement,  also dated the date hereof,  by and between the  Acquisition Sub and
the Holder.  The Companies shall complete the Asset Transfer no later than April
10, 2008, or as soon as practicable thereafter.

      In the event the  Companies  pay the New  Principal  Amount to the Holder,
either at their  option or  because  they are  required  to do so because of the
existence on the Payment Date of an NIR Default,  the Holder  acknowledges  that
the  Companies  shall not be  required  to pay more than  $6,000,000  of the New
Principal Amount in cash. Accordingly, the Companies shall pay the New Principal
Amount to the Holder as follows: (i) in cash, up to $6,000,000, representing the
Cash  Payment,  and (ii) the  balance of the New  Principal  Amount in excess of
$6,000,000 shall be converted  automatically and payable to the Holder in common
stock of Parent ("Common Stock"),  representing the Stock Payment.  In addition,
and subject to the sole and exclusive option of the Holder,  the Holder may also
elect to convert any portion of the Cash Payment over $3,500,000 to common stock
of the Parent (the "Qualified Portion"). The Stock Payment and, in the event the


                                       4
<PAGE>


Holder elects a Qualified  Portion,  shall be converted  into Common Stock based
upon the  average  bid and asked  sales  prices of the Common  Stock  during the
90-day  period  immediately  preceding  the  Effective  Date as  reported by the
applicable  exchange.  The Parent shall  calculate the amount of Common Stock to
which the Holder is entitled  and shall  issue  certificates  representing  such
shares to the Holder no later than 30 days  following  the Effective  Date.  The
Holder shall  exercise his option to designate a Qualified  Portion to be issued
as Common Stock by sending a complete Notice of Conversion, substantially in the
form attached hereto,  to the Parent within thirty (30) days of Holder's receipt
of the Cash Payment and Holder's check, representing the Qualified Portion.

      The  amount  of  Common  Stock  representing  the  Stock  Payment  and the
Qualified  Portion  shall not exceed 25% of the Common  Stock of the Parent then
outstanding,   assuming  the  issuance  of  shares  of  Common  Stock  hereunder
("Issuance Limit"). In the event the Issuance Limit would otherwise be exceeded,
the  Company  shall  issue such  shares of Common  Stock as equals the  Issuance
Limit, and shall also issue shares of convertible  preferred stock to the Holder
(the "Preferred  Stock"),  representing  the balance of either the Stock Payment
and/or  Qualified  Portion.   The  Preferred  Stock  shall  have  a  liquidation
preference  equal to the balance  remaining of the New Principal Amount not paid
in cash or immediately  converted and paid to the Holder in Common Stock. Twenty
percent  (20%) of the  Preferred  Stock shall be  automatically  converted  into
shares  of  Common  Stock on each of the  first  five  anniversary  dates of the
issuance of the  Preferred  Stock at a conversion  rate equal to the average bid
and asked price of the Common Stock for the 90 days prior to the Effective  Date
as reported by the applicable exchange, subject to the Issuance Limit.

      10.   Transfers of Note to Comply with the 1933 Act

      The Holder  agrees that this Note may not be sold,  transferred,  pledged,
hypothecated  or otherwise  disposed of except as follows:  (1) to a person whom
the Note may legally be transferred without registration and without delivery of
a current  prospectus  under  the 1933 Act with  respect  thereto  and then only
against  receipt of an agreement of such person to comply with the provisions of
this Section 10 with respect to any resale or other  disposition of the Note; or
(2) to any person upon delivery of a prospectus then meeting the requirements of
the 1933 Act relating to such securities and the offering  thereof for such sale
or disposition, and thereafter to all successive assignees.

      11.   Prepayment

            The Principal Amount may be prepaid by the Companies, in whole or in
part without  premium or penalty.  Upon any  prepayment of the entire  principal
amount of this  Note,  all  accrued,  but unpaid  interest  shall be paid to the
Holder on the date of prepayment. Nothing contained herein shall limit the right
of the Holder to receive the New Principal Amount.

            In the  event  the  Parent  agrees to permit the Holder to convert a
portion of the principal or interest on this Note,  or the Companies  prepay any
portion of the principal or interest on this Note, the Holder shall deliver this
Note to the Parent who shall issue a new note to the Holder, evidencing


                                       5
<PAGE>


any reduction of principal or interest so converted or prepaid.

      12.   Covenants of Companies

            The  Companies  covenant  to the  Holder  and  agree  that,  so long
as any principal of, or interest on, this Note shall remain  unpaid,  unless the
Holder shall  otherwise  consent in writing,  it will comply with the  following
terms:

            (a)  Reporting  Requirements.  The  Parent or  Acquisition  Sub,  as
applicable, will furnish to the Holder:

            (i) as soon as possible, and in any event within ten (10) days after
obtaining  knowledge  of the  occurrence  of  (A)  an  "Event  of  Default,"  as
hereinafter  defined, (B) an event which, with the giving of notice or the lapse
of time or both, would constitute an Event of Default, or (C) a material adverse
change in the condition or operations,  financial or otherwise, of the Parent or
Acquisition  Sub, taken as whole,  the written  statement of the Chief Executive
Officer or the Chief Financial Officer of the Parent and/or the Acquisition Sub,
setting  forth the details of such Event of Default,  event or material  adverse
change and the action which the Parent  and/or the  Acquisition  Sub proposes to
take with respect thereto;

            (ii) promptly after the commencement thereof, notice of each action,
suit or  proceeding  before any court or other  governmental  authority or other
regulatory body or any arbitrator as to which there is a reasonable  possibility
of a determination that would (A) materially impact the ability of the Parent or
Acquisition Sub to conduct its business, (B) materially and adversely affect the
business,  operations  or financial  condition of the Parent or the  Acquisition
Sub, or (C) impair the validity or  enforceability of the Note or the ability of
the Companies to perform their obligations under the Note.

            (b) Compliance with Laws. The Companies will comply, in all material
respects with all applicable laws, rules,  regulations and orders, except to the
extent  that  noncompliance  would not have a material  adverse  effect upon the
business, operations or financial condition of the Parent or the Acquisition Sub
taken as a whole.

            (c)  Preservation  of Existence.  So long as this Note  delivered by
Parent and  Acquisition  Sub to the Holder remains unpaid and  outstanding,  the
Parent and Acquisition Sub shall maintain their respective  corporate  existence
and shall not sell all or substantially all of their respective  assets,  except
in the event of a merger or consolidation or sale of all or substantially all of
their  assets,  where the  surviving  or  successor  entity in such  transaction
assumes the  Parent's and  Acquisition  Sub's  obligations  hereunder as well as
under a certain Asset Purchase Agreement and other "Parent Documents" as defined
therein, all dated the date hereof, between the parties hereto.



                                       6
<PAGE>


            (d)  Maintenance of Properties.  The Parent and Acquisition Sub will
each maintain and  preserve,  all of its  properties  which are necessary in the
proper  conduct of its business in good working  order and  condition,  ordinary
wear and tear excepted;  not divert any of the business or assets of Acquisition
Sub so as to reduce,  frustrate or diminish Holder's rights under this Note, the
Asset Purchase  Agreement,  the Security Agreement or the Intellectual  Security
Agreement,  and comply,  at all times with the provisions of all leases to which
it is a party as lessee or under  which it occupies  property,  so as to prevent
any forfeiture or material loss thereof or thereunder.

            (e)  Maintenance of Insurance.  The Companies  will  maintain,  with
responsible and reputable insurers, insurance with respect to its properties and
business,  in such amounts and covering such risks,  as is carried  generally in
accordance  with sound business  practice by companies in similar  businesses in
the same localities in which the Companies are situated.

            (f) Keeping of Records and Books of Account. The Companies will keep
adequate records and books of account,  with complete entries made in accordance
with generally accepted accounting  principles,  reflecting all of its financial
and other business transactions.

            (g) Compliance with the Securities  Exchange Act of 1934. The Parent
shall comply in all respects with the  requirements  of the Securities  Exchange
Act of 1934, including the timely filing of all reports due thereunder.

            (h)  Reservation of Common Stock.  The Parent further  covenants and
agrees that the Parent will at all times have authorized and reserved, free from
preemptive  rights, a sufficient number of shares of its common stock to provide
for the conversion of this Note in full.

      13.   Events of Default and Remedies

            (a) Any  one or  more  of the  following  events  which  shall  have
occurred  and be  continuing  shall  constitute  an event of default  ("Event of
Default"):

            (i) Default in the payment of interest  upon this Note,  as and when
the same shall become due; or

            (ii) Default in the payment of the  principal  of this Note,  as and
when the same shall become due; or

            (iii) The Companies shall fail to perform or observe any affirmative
covenant contained in this Note and such Default,  if capable of being remedied,
shall not have been  remedied ten (10) days after written  notice  thereof shall
have been given by the Holder to each of the Companies; or


                                       7
<PAGE>


            (iv)  The  Parent  or  Acquisition   Sub  (A)  shall  institute  any
proceeding or voluntary case seeking to adjudicate it bankrupt or insolvent,  or
seeking  dissolution,  liquidation,  winding  up  reorganization,   arrangement,
adjustment,  protection,  relief or composition of it or its debts under any law
relating to bankruptcy,  insolvency or reorganization  or relief of debtors,  or
seeking  the entry of any order for  relief or the  appointment  of a  receiver,
trustee,  custodian  or  other  similar  official  for such  the  Parent  or any
subsidiary or for any substantial part of its property,  or shall consent to the
commencement against it of such a proceeding or case, or shall file an answer in
any such case or proceeding commenced against it consenting to or acquiescing in
the commencement of such case or proceeding, or shall consent to or acquiesce in
the appointment of such a receiver,  trustee, custodian or similar official; (B)
shall be unable to pay its debts as such debts  become  due,  or shall  admit in
writing its  inability  to apply its debts  generally;  (C) shall make a general
assignment  for the  benefit  of  creditors;  or (D)  shall  take any  action to
authorize or effect any of the actions set forth above in this subsection 3(iv);
or

            (v) Any proceeding shall be instituted against the Companies seeking
to adjudicate it a bankrupt or insolvent,  or seeking dissolution,  liquidation,
winding  up,  reorganization,  arrangement,  adjustment,  protection,  relief of
debtors,  or seeking  the entry of an order for relief or the  appointment  of a
receiver,  trustee, custodian or other similar official for the Companies or for
any substantial part of its property,  and either such proceeding shall not have
been  dismissed or shall not have been stayed for a period of sixty (60) days or
any of the actions sought in such proceeding (including, without limitation, the
entry of any order for  relief  against  it or the  appointment  of a  receiver,
trustee,  custodian or other similar official for it or for any substantial part
of its property) shall occur; or

            (vi) One or more final  judgments or orders for the payment of money
in excess of $200,000 in the aggregate shall be rendered  against the Companies,
and either (A) enforcement proceedings shall have been commenced by any creditor
upon any such judgment or order, or (B) there shall be any period of thirty (30)
days  during  which  enforcement  of any such  judgment  or order  shall  not be
discharged, stayed or fully satisfied; or


            (vii) If, prior to the Payment Date, there is a sale,  conveyance or
disposition  of all or  substantially  all of the  assets  of the  Parent or the
Acquisition  Sub, the  effectuation  by the Parent or the  Acquisition  Sub of a
transaction  or series of  related  transactions  in which  more than 50% of the
voting  power  of  the  Parent  or  Acquisition  Sub  is  disposed  of,  or  the
consolidation, merger or other business combination of the Parent or Acquisition
Sub with or into any other Person (as defined  below) or Persons when the Parent
or  Acquisition  Sub is not  the  survivor,  and in the  event  of a  merger  or
consolidation or sale of all or substantially all of their assets, the surviving
or  successor  entity in such  transaction  fails to  assume  the  Parent's  and
Acquisition  Sub's  obligations  hereunder  as well as  under  a  certain  Asset
Purchase  Agreement and other "Parent  Documents" as defined therein,  all dated
the date hereof, between the parties hereto. "PERSON" shall mean any individual,
corporation, limited liability company, partnership, association, trust or other
entity or organization; or


                                       8
<PAGE>


            (viii)  upon any  default by the  Parent,  Acquisition  Sub or other
party  under  the "NIR  Letter",  dated  January  31,  2005,  a copy of which is
attached hereto, or under the "Debt Instruments" identified therein.


            (b) If an Event of Default  described  above has occurred,  then the
Holder may,  without  further  notice to the  Companies,  declare the  principal
amount  of this  Note at the time  outstanding,  together  with  accrued  unpaid
interest thereon,  and all other amounts payable under this Note to be forthwith
due and payable,  whereupon such principal,  interest and all such amounts shall
become and be forthwith due and payable.

            (c)  The  Companies  covenant  that  in  case  the principal of, and
accrued  interest  on,  the Note  becomes  due and  payable  by  declaration  or
otherwise,  then the Companies  will pay in cash to the Holder of this Note, the
whole  amount  that then  shall  have  become  due and  payable on this Note for
principal or interest, as the case may be, and in addition thereto, such further
amount as shall be  sufficient  to cover the costs and  expenses of  collection,
including  reasonable fees and  disbursements of the Holder's legal counsel.  In
case the  Companies  shall fail  forthwith  to pay such  amount,  the Holder may
commence an action or proceeding  at law or in equity for the  collection of the
sums so due and  unpaid,  and may  prosecute  any such action or  proceeding  to
judgment or final  decree  against  Companies  or other  obligor upon this Note,
wherever  situated,  the  monies  adjudicated  or  decreed  to be  payable.  The
Companies  hereby  waive notice of default,  presentment  or demand for payment,
protest or notice of  nonpayment  or dishonor  and all other  notices or demands
relative to this Note.

      14.   Miscellaneous

            (a)  This  Note  has  been  issued  by  the  Companies  pursuant  to
authorization of the Boards of Directors of the Companies.

            (b) The  Companies  may  consider and treat the entity in whose name
this Note shall be  registered  as the absolute  owner  thereof for all purposes
whatsoever  (whether or not this Note shall be overdue) and the Companies  shall
not be affected by any notice to the contrary. Subject to the limitations herein
stated,  the registered owner of this Note shall have the right to transfer this
Note by assignment,  and the transferee  thereof shall, upon his registration as
owner  of this  Note,  become  vested  with all the  powers  and  rights  of the
transferor. Registration of any new owners shall take place upon presentation of
this  Note  to  the  Parent  at  its  principal  offices,  together  with a duly
authenticated  assignment.  In  case  of  transfer  by  operation  of  law,  the
transferee  agrees to notify the  Companies of such transfer and of his address,
and to submit appropriate  evidence regarding the transfer so that this Note may
be registered in the name of the transferee.  This Note is transferable  only on
the books of the Parent by the holder hereof,  in person or by attorney,  on the
surrender  hereof,  duly endorsed.  Communications  sent to any registered owner
shall be  effective  as  against  all  holders  or  transferees  of the Note not
registered at the time of sending the communication.


                                       9
<PAGE>


            (c)  Payments of principal  and interest  shall be made as specified
above to the  registered  owner of this Note.  No interest  shall be due on this
Note for such period of time that may elapse  between the  maturity of this Note
and its presentation for payment.

            (d) The Holder  shall not,  by virtue,  hereof,  be  entitled to any
rights of a  shareholder  in the  Parent,  whether at law or in equity,  and the
rights of the Holder are limited to those expressed in this Note.

            (e)  Upon   receipt  by  the   Companies   of  evidence   reasonably
satisfactory to it of the loss,  theft,  destruction or mutilation of this Note,
and (in the  case of loss,  theft or  destruction)  of  reasonably  satisfactory
indemnification, and upon surrender and cancellation of this Note, if mutilated,
the Parent shall execute and deliver a new Note of like tenor and date.

            (f) This Note shall be construed and enforced in accordance with the
laws of the State of New Jersey.  The Companies and the Holder hereby consent to
the  jurisdiction  of any  federal  or state  court  located in the State of New
Jersey in  connection  with any action  concerning  the  provisions of this Note
instituted by the Holder against the Companies.

            (g) The Parent and Acquisition Sub, jointly and severally, represent
to the Holder that they have  reviewed all of the terms and  provisions  of this
Note with their  respective  counsel  and  performed  such due  diligence  as is
necessary  to  conclude  that all of the  terms  and  provisions  of this  Note,
including all of the payments required  hereunder,  to their best knowledge,  do
not violate any usury statute of the State of New Jersey.


                                       10
<PAGE>

            IN WITNESS WHEREOF, Digital Descriptor Systems, Inc. and CGM Applied
Security Technologies, Inc. caused this Note to be signed in each of their names
by their Chief Executive Officer.

                                    DIGITAL DESCRIPTOR SYSTEMS, INC.


                                    By: /s/ Anthony R. Shupin
                                        ----------------------------------------
                                        Anthony R. Shupin
                                        President and Chief Executive Officer


                                    CGM APPLIED SECURITY TECHNOLOGIES, INC.


                                    By: /s/ Anthony R. Shupin
                                        ----------------------------------------
                                        Anthony R. Shupin
                                        President and Chief Executive Officer



                                       11
<PAGE>


                              NOTICE OF CONVERSION

(To be executed by the Registered Holder in order to convert the Note)


      The undersigned  hereby elects to convert  $_________ of the principal and
$_________ of the interest due on the Note issued by DIGITAL DESCRIPTOR SYSTEMS,
INC. and CGM APPLIED SECURITY TECHNOLOGIES,  INC. into Common Stock according to
the  conditions  set  forth in such  Note,  as of the date  written  below.  The
undersigned  further affirms that as of the date hereof, the representations and
warranties  made by the undersigned in the  subscription  agreement of even date
with the  promissory  note  being  converted,  are true and  correct  as if such
representations and warranties were made as of the date hereof.



Date of Conversion:
                    ------------------------------------------------------------

Conversion Price:  $____________per share


Shares To Be Delivered:
                       ---------------------------------------------------------

Signature:
          ----------------------------------------------------------------------

Print Name:
           ---------------------------------------------------------------------

Address:
        ------------------------------------------------------------------------




                                       12
<PAGE>

                        DIGITAL DESCRIPTOR SYSTEMS, INC.
                           2150 Highway 35, Suite 250
                           Sea Girt, New Jersey 08750




                                         January 31, 2005



AJW Partners, LLC
New Millennium Capital Partners II, LLC
AJW Offshore, Ltd. (f/d/a AJW/New Millennium Offshore, Ltd.)
AJW Qualified Partners, LLC (f/d/a Pegasus Capital Partners, LLC)
1044 Northern Boulevard
Suite 302
Roslyn, New York 11576

      Re:   Digital Descriptor Systems, Inc. (the "Company") -
            Acquisition of CGM Security Solutions, Inc.
            --------------------------------------------------

Ladies and Gentlemen:

      In connection with the Company's proposed acquisition of CGM Security
Solutions, Inc. ("CGM") (the "Acquisition"), this letter sets forth the
agreement of the parties hereto to: (i) extend the maturity dates of certain
debentures and notes which are convertible into shares of the Company's common
stock, par value $.001 per share (the "Common Stock"), originally issued by the
Company to the investors listed in the signature pages hereto (collectively, the
"Investors") (collectively, the "Debt Instruments"), as set forth on Schedule 1
hereto; (ii) refrain from incurring liens on the assets of the Company,
including those CGM assets purchased in the Acquisition (the "CGM Assets"),
except as provided herein; (iii) allow the Company to cure any Event of Default
(as defined in each of the Debt Instruments) within one hundred fifty days (150)
days from the date hereof; (iv) agree that a failure to pay the entire purchase
price for the CGM Assets to CGM's former shareholder pursuant to the terms of a
certain 2.86% secured convertible promissory note, dated February 24, 2005, and
given by the Company and its subsidiary to CGM (the "Note"), shall not
constitute an Event of Default under the Debt Instruments and hereby agree to
release the Investors' liens on the CGM Assets in the event of a default under
the Note; and (v) extend the expiration dates and amend the exercise price of
certain warrants originally issued by the Company to the Investors
(collectively, the "Warrants"), as set forth on Schedule 1 hereto.

      By execution hereof, for good and valuable consideration the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree that:

      1.    The Maturity Date of the Debt Instruments issued on November 30,
            2004 is hereby extended until March 1, 2008.

                                       13
<PAGE>


      2.    The Applicable Percentage (as defined in each of the Debt
            Instruments) shall be 40%.

      3.    So long as the Company shall have any obligations under the Debt
            Instruments, the Company shall not, without the Investors' written
            consent, transfer, pledge, hypothecate, encumber, license (except
            for non-exclusive licenses granted by the Company in the ordinary
            course of business), sell or otherwise dispose of any of the assets
            of the Company; provided that, in connection with the Acquisition,
            the Company shall grant a second priority security interest in the
            CGM Assets to the former shareholder of CGM (but not any other
            assets of the Company or any subsidiary of the Company); and further
            provided that, so long as the Company shall have any obligations
            under the Debt Instruments, the Company shall maintain a valid and
            perfected first priority security interest in favor of the Investors
            in the assets of CGM or any successor thereto.

      4.    The Investors agree to allow the Company to cure, on or prior to
            June 30, 2005, any Events of Default (as defined in each of the Debt
            Instruments), which have occurred as of the date hereof or occur on
            or prior to June 30, 2005 pursuant to the Debt Instruments; provided
            that all interest due and owing to the Investors pursuant to the
            Debt Instruments shall remain payable to the Investors in accordance
            with the terms and conditions set forth in the Debt Instruments.

      5.    The Investors agree that, in the event that the Company and its
            subsidiary fail to pay the entire purchase price for the CGM Assets
            to CGM or its assigns pursuant to the terms of the Note and,
            provided further, that an Event of Default has not occurred pursuant
            to any of the Debt Instruments, such failure to pay the Note and the
            exercise by CGM or its assigns of any rights as a result thereof
            shall not constitute an Event of Default under the terms and
            conditions set forth in any of the Debt Instruments, and CGM, as the
            holder of the Note, may exercise its remedies pursuant to the Note,
            which may include the retaking of the CGM Assets, in which event the
            Investors hereby agree to release their first priority security
            interest and liens on the CGM Assets to accommodate CGM.

      6.    The Warrants shall expire on January 31, 2012.

      7.    The Exercise Price (as defined in the Warrants) is hereby amended to
            be $.001 per share.

      8.    The Debt Instruments and the Warrants are hereby amended in
            accordance with the foregoing provisions. All other provisions of
            the Debt Instruments and the Warrants, as amended from time to time,
            shall remain in full force and effect.

      The parties shall do and perform, or cause to be done and performed, all
such further acts and things, and shall execute and deliver all such other
agreements, certificates, instruments and documents, as the other parties hereto
may reasonably request in order to carry out the intent an accomplish the
purposes of this letter agreement, including without limitation the issuance of
amended Debt Instruments and the Warrants.

                                       14
<PAGE>


      Please signify your agreement with the foregoing by signing a copy of this
letter where indicated and returning it to the undersigned.



                                          Sincerely,

                                          DIGITAL DESCRIPTOR SYSTEMS, INC.


                                          /s/ Anthony R. Shupin
                                          -------------------------------
                                          Anthony R. Shupin
                                          President and Chief Executive Officer

ACCEPTED AND AGREED:

AJW PARTNERS, LLC.
By:  SMS GROUP, LLC

/s/ Corey S. Ribotsky
-----------------------------
Corey S. Ribotsky, Manager


NEW MILLENNIUM CAPITAL PARTNERS II, LLC
By:  FIRST STREET MANAGER II, LLC,

/s/ Corey S. Ribotsky
-----------------------------
Corey S. Ribotsky, Manager


AJW OFFSHORE, LTD.
By:  FIRST STREET MANAGER II, LLC

/s/ Corey S. Ribotsky
------------------------------
Corey S. Ribotsky, Manager

AJW QUALIFIED PARTNERS, LLC
By:  AJW MANAGER, LLC

/s/ Corey S. Ribotsky
------------------------------
Corey S. Ribotsky, Manager
                                       15

<PAGE>



                                   SCHEDULE 1


<TABLE>
<CAPTION>
                                                 Debt Instruments   Warrants    Date of Issuance
                                                 ----------------  ----------  ------------------
<S>                                              <C>                  <C>               <C> <C>
      AJW Partners LLC                           $    125,000         375,000  December 31, 2001
      1044 Northern Blvd. Suite 302              $     75,000         225,000  January 10, 2003
      Roslyn, New York 11576                     $     37,500         112,500  February 27, 2003
                                                 $     37,500         112,500  March 31, 2003
                                                 $     50,000         150,000  May 7, 2004
                                                 $    560,000       1,680,000  November 30, 2004
                                                 ----------------  ----------  ------------------
      New Millennium Capital Partners II, LLC    $    125,000         375,000  December 31, 2001
      1044 Northern Blvd. Suite 302              $     10,175          30,525  May 7, 2004
      Roslyn, New York 11576                     $     70,000         210,000  November 30, 2004
                                                 ----------------  ----------  ------------------
      AJW Offshore, Ltd.                         $     50,000         150,000  September 30, 2002
      1044 Northern Blvd. Suite 302              $    100,000         300,000  January 10, 2003
      Roslyn, New York 11576                     $     50,000         150,000  February 27, 2003
                                                 $     50,000         150,000  March 31, 2003
                                                 $     82,500         577,500  September 30, 2003
                                                 $     22,500         157,500  November 27, 2003
                                                 $     22,500         157,500  December 3, 2003
                                                 $     22,500         157,500  February 2, 2004
                                                 $     88,700         266,100  May 7, 2004
                                                 $  1,435,000       4,305,000  November 30, 2004
                                                 ----------------  ----------  ------------------
      AJW Qualified Partners, LLC                $     50,000         150,000  September 30, 2002
      1044 Northern Blvd. Suite 302              $     75,000         225,000  January 10,2003
      Roslyn, New York 11576                     $     37,500         112,500  February 27, 2003
                                                 $     37,500         112,500  March 31, 2003
                                                 $     82,500         577,500  September 30, 2003
                                                 $     22,500         157,500  November 27, 2003
                                                 $     22,500         157,500  December 3, 2003
                                                 $     22,500         157,500  February 2, 2004
                                                 $    101,125         303,375  May 7, 2004
                                                 $  1,435,000       4,305,000  November 30, 2004
                                                 ----------------  ----------  ------------------
</TABLE>


                                       16