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                                                                     EXHIBIT 3.1

                          CERTIFICATE OF INCORPORATION
                                       OF
                              DATUM DELAWARE, INC.
                            (A DELAWARE CORPORATION)


         FIRST:  The name of the corporation is Datum Delaware, Inc. (the
"Corporation").

         SECOND:  The address of the registered office of the Corporation in
the State of Delaware is Corporation Trust Center, 1209 Orange Street, in the
City of Wilmington, County of New Castle.  The name and address of the
registered agent of the Corporation is The Corporation Trust Company,
Corporation Trust Center, 1209 Orange Street, in the City of Wilmington, County
of New Castle, State of Delaware 19801.

         THIRD:  The purpose of the Corporation is to engage in any lawful act
or activity for which corporations may be organized under the General
Corporation Law of the State of Delaware.

         FOURTH:  The Corporation is authorized to issue one class of shares of
stock to be designated "Common."  The total number of shares that the
corporation is authorized to issue is five million (5,000,000) shares.  The
Common shares shall each have a twenty-five cents ($.25) par value.  The
aggregate par value is one million two hundred fifty thousand dollars
($1,250,000).

         FIFTH:  The business and affairs of the Corporation shall be managed
by or under the direction of the Board of Directors.  The directors shall be
divided into three classes, designated Class I, Class II and Class III.  Each
class shall consist, as nearly as may be possible, of one-third of the total
number of directors constituting the entire Board of Directors.  The term of
the initial Class I directors shall terminate on the date of the 1988 annual
meeting of stockholders; the term of the initial Class II directors shall
terminate on the date of the 1989 annual meeting of stockholders and the term
of the initial Class III directors shall terminate on the date of the 1990
annual meeting of stockholders.  At each annual meeting of stockholders
beginning in 1988, successors to the class of directors whose term expires at
that annual meeting shall be elected for a three-year term.  If the number of
directors is changed, any increase or decrease shall be apportioned among the
classes so as to maintain the number of directors in each class as nearly equal
as possible, and any additional directors of any class elected to fill a
vacancy resulting from an increase in such class will hold office for a term
that shall coincide with the remaining term of that class, but in no case shall
a decrease in the number of directors shorten the term of any incumbent
director.  A director shall hold office until the annual meeting for the year
in which his term expires and until his successor shall be elected and shall
qualify, subject, however, to prior death, resignation, retirement,
disqualification or removal from office.

         SIXTH:  A director shall not be personally liable to the Corporation
or its stockholders for monetary damages for breach of fiduciary duty as a
director; provided that this sentence shall not eliminate or limit the
liability of a director (i) for any breach of his duty of loyalty to the
Corporation or its shareholders, (ii) for acts or omissions not in good faith
or which involve intentional misconduct or a knowing violation of the law,
(iii) under Section 174 of the General
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Corporation Law, or (iv) for any transaction from which the director derives an
improper personal benefit.

         SEVENTH:  Except as expressly set forth herein or as otherwise
provided by law, the board of directors is empowered to adopt bylaws, and amend
the same from time to time, by a majority vote of the directors pertaining to
any matter that is pertinent to the business of the Corporation and as
permitted by law.

         EIGHTH:  This Certificate of Incorporation may be amended by a
majority vote of the authorized and outstanding Common shares.

         NINTH:  The incorporator is V. A. Brookens, whose mailing address is
1209 Orange Street, Wilmington, Delaware 19801.

         I, THE UNDERSIGNED, being the incorporator, for the purpose of forming
a corporation under the laws of the State of Delaware do make, file and record
this Certificate of Incorporation, do certify that the facts herein stated are
true, and, accordingly, have hereto set my hand and seal this 15th day of
April, 1987.


                                                By: /s/ V. A. Brookens
                                                    ----------------------------
                                                    V. A. Brookens, Incorporator


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                              AGREEMENT OF MERGER


         THIS AGREEMENT OF MERGER, dated as of April 20, 1987, is entered into
between Datum, Inc., a California corporation ("Datum California"), and Datum
Delaware, Inc., a Delaware corporation ("Datum Delaware").  Datum California
and Datum Delaware are hereinafter sometimes collectively referred to as the
"Constituent Corporations."

                                   RECITALS:

         A.      Datum California is a corporation duly organized and existing
under the laws of the State of California;

         B.      Datum Delaware is a corporation duly organized and existing
under the laws of the State of Delaware;

         C.      On the date of this Agreement, Datum California has authority
to issue 5,000,000 shares of twenty-five cents ($.25) par value Common Stock
("California Common Stock"), of which 2,728,890 shares are issued and
outstanding or reserved for issuance at the date hereof;

         D.      On the date of this Agreement, Datum Delaware has authority to
issue 5,000,000 shares of Common Stock, par value twenty-five cents ($.25) per
share ("Delaware Common Stock"), 1,000 shares of which are issued and
outstanding and owned by Datum California;

         E.      The Boards of Directors of Datum California and Datum Delaware
have determined that it is advisable and in the best interest of their
respective corporations that Datum California merge with and into Datum
Delaware upon the terms and subject to the conditions set forth in this
Agreement for the purpose of effecting the change of the state of incorporation
of Datum California from California to Delaware;

         F.      The respective Boards of Directors of Datum California and
Datum Delaware have, by resolutions duly adopted, approved this Agreement;

         G.      Datum California has approved this Agreement as the sole
stockholder of Datum Delaware, and

         H.      The Board of Directors of Datum California has directed that
this Agreement be submitted to a vote of its shareholders.

         NOW, THEREFORE, in consideration of the mutual agreements and
covenants set forth herein, Datum California and Datum Delaware hereby agree as
follows:

         1.      Merger.  Datum California shall be merged with and into Datum
Delaware (the "Merger"), and Datum Delaware shall be the surviving corporation
(hereinafter sometimes referred to as the "Surviving Corporation").  The Merger
shall become effective upon the date and at the time of filing of an
appropriate certificate of merger, providing for the Merger, with the Secretary
of State of the State of California and an appropriate certificate of merger,





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providing for the Merger, with the Secretary of State of Delaware, whichever
later occurs (the "Effective Time").

         2.      Governing Documents.  The Certificate of Incorporation of
Datum Delaware, as in effect immediately prior to the Effective Time, shall be
the Certificate of Incorporation of the Surviving Corporation without change or
amendment until thereafter amended in accordance with the provisions thereof
and applicable laws, except that at the Effective Time, Article First of said
Certificate of Incorporation shall be amended to read in its entirety as
follows:  "The name of the corporation is Datum Inc. (hereinafter referred to
as the "Corporation")."  The bylaws of Datum Delaware, as in effect immediately
prior to the Effective Time, shall be the bylaws of the Surviving Corporation,
without change or amendment until thereafter amended in accordance with the
provisions thereof, the provisions of the Certificate of Incorporation of the
Surviving Corporation and applicable laws.

         3.      Succession.  At the Effective Time, the separate corporate
existence of Datum California shall cease, and Datum Delaware shall possess all
the rights, privileges, powers and franchises of a public and private nature
and be subject to all the restrictions, disabilities and duties of each of the
Constituent Corporations and all and singular, the rights, privileges, powers
and franchises of each of the Constituent Corporations, and all property, real,
personal and mixed, and all debts due to each of the Constituent Corporations,
shall be vested in the Surviving Corporation and all property, rights,
privileges, powers and franchises, and all and every other interest, shall be
thereafter as effectually the property of the Surviving Corporation as they
were of the respective Constituent Corporations, and the title to any real
estate vested by deed or otherwise in either of such Constituent Corporations
shall not revert or be in any way impaired by reason of the Merger, but all
rights of creditors and all liens upon any property of Datum California shall
be preserved and unimpaired.  To the extent permitted by law, any claim
existing or action or proceeding pending by or against either of the
Constituent Corporations may be prosecuted as if the Merger had not taken
place.  All debts, liabilities and duties of the respective Constituent
Corporations shall thenceforth attach to the Surviving Corporation and may be
enforced against it to the same extent as if such debts, liabilities and duties
had been incurred or contracted by it.  All corporate acts, plans, policies,
agreements, arrangements, approvals and authorizations of Datum California, its
stockholders, Board of Directors and committees thereof, officers and agents
which were valid and effective immediately prior to the Effective Time, shall
be taken for all purposes as the acts, plans, policies, agreements,
arrangements, approvals and authorizations of the Surviving Corporation and
shall be as effective and binding thereon as the same were with respect to
Datum California.  The employees and agents of Datum California shall become
the employees and agents of the Surviving Corporation and continue to be
entitled to the same rights and benefits which they enjoyed as employees and
agents of Datum California, subject to the same limitations with respect
thereto.  The requirements of any plans or agreements of Datum California
involving the issuance or purchase by Datum California of certain shares of its
capital stock shall be satisfied by the issuance or purchase of a like number
of shares of the Surviving Corporation.

         4.      Directors and Officers.  The directors and officers of Datum
California at the Effective Time shall be and become directors and officers,
holding the same titles and positions, of the Surviving Corporation at the
Effective Time, and after the Effective Time shall serve in accordance with the
bylaws of the Surviving Corporation.





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         5.      Further Assurances.  From time to time, as and when required
by the Surviving Corporation or by its successors or assigns, there shall be
executed and delivered on behalf of Datum California such deeds and other
instruments, and there shall be taken or caused to be taken by it all such
further and other actions, as shall be appropriate, advisable or necessary in
order to vest, perfect or confirm, of record or otherwise, in the Surviving
Corporation the title to and possession of all property, interests, assets,
rights, privileges, immunities, powers, franchises and authority of Datum
California, and otherwise to carry out the purposes of this Agreement, and the
officers and directors of the Surviving Corporation are fully authorized in the
name and on behalf of Datum California otherwise, to take any and all such
action and to execute and deliver any and all such deeds and other instruments.

         6.      Conversion of Shares.  At the Effective Time, by virtue of the
Merger and without any action on the part of the holder thereof:

                 (a)      each share of California Common Stock outstanding
         immediately prior to the Effective Time shall be changed and converted
         into and shall be one fully paid and nonassessable share of Delaware
         Common Stock; and

                 (b)      the 1,000 shares of Delaware Common Stock presently
         issued and outstanding in the name of Datum California shall be
         cancelled and retired and resume the status of authorized and unissued
         shares of Delaware Common Stock, and no shares of Delaware Common
         Stock or other securities of Datum Delaware shall be issued in respect
         thereof.

         7.      Condition to Merger.  The Merger shall have received the
requisite approval of the holders of California Common Stock pursuant to the
Corporations Code of the State of California.

         8.      Stock Certificates.  At and after the Effective Time, all of
the outstanding certificates which, immediately prior to the Effective Time,
represented shares of California Common Stock shall be deemed for all purposes
to evidence ownership of, and to represent, as the case may be, shares of
Delaware Common Stock into which the shares of California Common Stock,
formerly represented by such certificates, have been converted as herein
provided.  The registered owner on the books and records of the Surviving
Corporation or its transfer agents of any such outstanding stock certificate
shall, until such certificate shall have been surrendered for transfer or
otherwise accounted for to the Surviving Corporation or its transfer agents,
have and be entitled to exercise any voting and other rights with respect to,
and to receive any dividends and other distributions upon, the shares of Datum
Delaware evidenced by such outstanding certificate as above provided.

         9.      Options.  Each (i) option to purchase shares of California
Common Stock granted under the 1984 Stock Option Plan and right to receive
shares of California Common Stock granted under the 1981 Restricted Stock Award
Plan of Datum California (the "Plans") and (ii) other warrant or option to
purchase shares of California Common Stock which is outstanding immediately
prior to the Effective Time, shall, by virtue of the Merger and without any
action on the part of the holder thereof, be converted into and become an
option, right or warrant, as the case may be, to purchase or receive the same
number of shares of Delaware Common Stock upon the same terms and subject to
the same conditions as set forth in the Plans or other warrants or





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option agreements with respect thereto as in effect at the Effective Time.  The
same number of shares of Datum Delaware Common Stock shall be reserved for
purposes of said Plans or other warrants or options as is equal to the number
of shares of Datum California Common Stock so reserved as of the Effective
Time.  As of the Effective Time, Datum Delaware hereby assumes the Plans and
all obligations of Datum California under the Plans (including the outstanding
options and rights or portions thereof granted pursuant to the Plans) as well
as all other warrants and options of Datum California and any agreements of
Datum California with respect thereto.

         10.     Other Employee Benefit Plans.  As of the Effective Time, Datum
Delaware hereby assumes all obligations under any and all employee benefit
plans of Datum California in effect as of the Effective Time or with respect to
which employee rights or accrued benefits are outstanding as of the Effective
Time.

         11.     Amendment.  Subject to applicable laws, this Agreement may be
amended, modified or supplemented by written agreement of the parties hereto at
any time prior to the Effective Time with respect to any of the terms contained
herein; provided, however, that no such amendment, modification or supplement
not adopted and approved by the shareholders of Datum California and Datum
Delaware shall affect the rights of the shareholders of either or both such
corporations in a manner which is materially adverse to the shareholders of
either or both such corporations.

         12.     Abandonment.  At any time prior to the Effective Time, this
Agreement may be terminated and the Merger may be abandoned by the Board of
Directors of Datum California, notwithstanding approval of this Agreement by
the shareholder of Datum Delaware or by the shareholders of Datum California,
or both, if in the opinion of such Board of Directors, the Merger is for any
reason inadvisable.

         13.     Binding Effect.  This Agreement shall be binding upon and
shall inure to the benefit of the parties and their respective successors and
assigns; provided, however, that this Agreement may not be assigned to any
party without the prior written consent of the other party hereto.





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         IN WITNESS WHEREOF, Datum California and Datum Delaware have caused
this Agreement to be signed by their respective duly authorized officers as of
the date first above written.

                                        DATUM INC., a California corporation


                                        By:  /s/ Louis B. Horwitz 
                                             ---------------------------
                                             Louis B. Horwitz, President


ATTEST:

By  /s/ Benjamin F. Tarver                
    -----------------------------
    Benjamin F. Tarver, Secretary


                                        DATUM DELAWARE, INC.,
                                        a Delaware corporation


                                        By: /s/ Louis B. Horwitz 
                                            ---------------------------
                                            Louis B. Horwitz, President


ATTEST:

By: /s/ Benjamin F. Tarver                 
    -----------------------------
    Benjamin F. Tarver, Secretary





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                              DATUM DELAWARE, INC.

                            CERTIFICATE OF SECRETARY

         I, BENJAMIN F. TARVER, the Secretary of DATUM DELAWARE, INC. ("DATUM
DELAWARE"), a corporation organized and existing under the laws of the State of
Delaware, hereby certify that the Agreement of Merger to which this Certificate
is attached, having been duly signed on behalf of DATUM DELAWARE and having
been signed on behalf of DATUM, INC., a corporation of the State of California,
was duly adopted pursuant to Delaware General Corporation Law Section 228 by
the unanimous written consent of the stockholders holding 1,000 shares of the
capital stock of DATUM DELAWARE, the same being all of the shares issued and
outstanding having voting power, and that thereby the Agreement of Merger was
adopted as the act of the stockholders of DATUM DELAWARE and the duly adopted
agreement and act of said corporation.

         WITNESSED my hand this 5th day of June, 1987.


                                                /s/ BENJAMIN F. TARVER 
                                                -----------------------------
                                                Benjamin F. Tarver, Secretary



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                                   DATUM INC.

                            CERTIFICATE OF SECRETARY

         I, BENJAMIN F. TARVER, the Secretary of DATUM INC. (the "Company"), a
corporation organized and existing under the laws of the State of California,
hereby certify that the Agreement of Merger to which this Certificate is
attached, having been duly signed on behalf of the Company and having been
signed on behalf of DATUM DELAWARE, INC., a corporation of the State of
Delaware, was duly approved and adopted at the Company's Annual Meeting of
Stockholders held on May 27, 1987 by the holders of a majority of the
outstanding stock entitled to vote, and that such number equaled or exceeded
the vote required thereon, and that thereby the Agreement of Merger was adopted
as the act of the stockholders of the Company and the duly adopted agreement
and act of said corporation.

         WITNESSED my hand this 5th day of June, 1987.


                                                /s/ BENJAMIN F. TARVER 
                                                -----------------------------
                                                Benjamin F. Tarver, Secretary



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                            CERTIFICATE OF AMENDMENT
                                       OF
                          CERTIFICATE OF INCORPORATION
                                       OF
                                  DATUM INC.,
                             A DELAWARE CORPORATION


       (Pursuant to Section 242 of the Delaware General Corporation Law)


         DATUM INC., a corporation organized and existing under and by virtue
of the Delaware General Corporation Law (the "Corporation"), does hereby
certify that:

         FIRST:  At a duly held meeting of the Board of Directors of the
Corporation, the Board of Directors of the Corporation duly adopted a
resolution setting forth an amendment to the Certificate of Incorporation of
the Corporation, declaring said amendment to be advisable and directing that
said amendment be submitted to the stockholders of the Corporation for
consideration thereof.  The resolution setting forth the proposed amendment is
as follows:

                 "NOW, THEREFORE, BE IT RESOLVED, that Article Fourth of the
         Corporation's Certificate of Incorporation be amended and restated to
         read as follows:

                 The Corporation is authorized to issue one class of shares of
                 stock to be designated "Common."  The total number of shares
                 that the Corporation is authorized to issue is eight million
                 (8,000,000) shares.  The common shares shall each have a
                 twenty-five cents ($.25) par value."

         SECOND: That thereafter, pursuant to resolution of its Board of
Directors, a Special Meeting of the Stockholders of the Corporation was duly
called and held, upon notice in accordance with Section 222 of the Delaware
General Corporation Law, at which meeting the necessary number of shares as
required by statute were voted in favor of the amendment.

         THIRD:  Said amendment was duly adopted in accordance with the
provisions of Section 242 of the Delaware General Corporation Law.





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         IN WITNESS WHEREOF, DATUM INC. has caused this Certificate of
Amendment to be signed by Louis B. Horwitz, its duly authorized Chairman and
President, this 16th day of March, 1995.

                                        DATUM INC.,
                                        a Delaware corporation



                                        By:  /s/ LOUIS B. HORWITZ 
                                             ------------------------------
                                             Louis B. Horwitz 
                                             Chairman and President





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                            CERTIFICATE OF AMENDMENT
                                       OF
                          CERTIFICATE OF INCORPORATION
                                       OF
                                  DATUM INC.,
                             A DELAWARE CORPORATION


       (Pursuant to Section 242 of the Delaware General Corporation Law)


         DATUM INC., a corporation organized and existing under and by virtue
of the Delaware General Corporation Law (the "Corporation"), does hereby
certify that:

         FIRST:  At a duly held meeting of the Board of Directors of the
Corporation, the Board of Directors of the Corporation duly adopted a
resolution setting forth an amendment to the Certificate of Incorporation of
the Corporation, declaring said amendment to be advisable and directing that
said amendment be submitted to the stockholders of the Corporation for
consideration thereof.  The resolution setting forth the proposed amendment is
as follows:

                 "NOW, THEREFORE, BE IT RESOLVED, that Article Fourth of the
         Corporation's Certificate of Incorporation be amended and restated to
         read as follows:

                 FOURTH:  The total number of shares of stock which the
                 Corporation shall have the authority to issue is eleven
                 million (11,000,000) shares, consisting of a class of one
                 million (1,000,000) shares of Preferred Stock par value $.25
                 per share, and a class of ten million (10,000,000) shares of
                 Common Stock par value $.25 per share, (the Preferred Stock,
                 par value $.25 per share, being herein referred to as
                 "Preferred Stock"; and the Common Stock, par value $.25 per
                 share, being herein referred to as "Common Stock").  The Board
                 of Directors is expressly authorized to provide for the
                 issuance of the shares of Preferred Stock in one or more
                 series and, by filing a Certificate pursuant to the applicable
                 law of the State of Delaware, to establish from time to time
                 the number of shares to be included in each series, and to fix
                 the designations, powers, preferences and relative,
                 participation, optional or other special rights, if any, of
                 the shares of each such series and the qualifications,
                 limitations and restrictions thereof, if any, with respect to
                 each such series of Preferred Stock.

         SECOND: That thereafter, pursuant to resolution of its Board of
Directors, an Annual  Meeting of the Stockholders of the Corporation was duly
called and held, upon notice in accordance with Section 222 of the Delaware
General Corporation Law, at which meeting the necessary number of shares as
required by statute were voted in favor of the amendment.
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         THIRD:  Said amendment was duly adopted in accordance with the
provisions of Section 242 of the Delaware General Corporation Law.

         IN WITNESS WHEREOF, DATUM INC. has caused this Certificate of
Amendment to be signed by Louis B. Horwitz, its duly authorized Chairman and
President, this 11th day of June, 1996.

                                                   DATUM INC.,
                                                   a Delaware corporation



                                                   By: /s/ LOUIS B. HORWITZ 
                                                       -----------------------
                                                       Louis B. Horwitz 
                                                       Chairman and President





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