<PAGE>   1
                                  UNITED STATES

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                    FORM 10-Q

(Mark One)
[X]   QUARTERLY REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE 
      ACT OF 1934

               For the quarterly period ended March 31, 1998.

                                       OR

[ ]  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES 
     EXCHANGE ACT OF 1934

   For the transition period from __________________ to __________________ .

                           Commission file no. 0-6272

                                   DATUM INC.
             (Exact name of registrant as specified in its charter)

           DELAWARE                                         95-2512237 
(State or other jurisdiction of                          (I.R.S. Employer 
incorporation or organization)                           Identification No.

      9975 TOLEDO WAY, IRVINE, CA                            92618-1819
(Address of principal executive offices)                     (Zip code)

                                 (949) 598-7500
              (Registrant's telephone number, including area code)

                                 NOT APPLICABLE
              (Former name, former address and former fiscal year,
                         if changed since last report)

Indicate by a check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to the
filing requirements for the past 90 days. YES  X . NO    .
                                              ---    ---

The registrant had 5,391,077 shares of common stock outstanding as of April 30,
1998.

Total number of sequentially numbered pages contained herein are: _____


<PAGE>   2

                                      INDEX


<TABLE>
<S>            <C>                                                     <C>
PART I.        FINANCIAL INFORMATION

Item 1.        Financial Statements.................................... 3

Item 2.        Management's Discussion and Analysis of
               Financial Condition and Results of Operations........... 8


PART II.       OTHER INFORMATION

Item 6.        Exhibits and Reports on Form 8-K........................12

               Signatures..............................................13

               Exhibit Index...........................................14
</TABLE>

<PAGE>   3

                          PART I. FINANCIAL INFORMATION


Item 1.      Financial Statements


                           DATUM INC. AND SUBSIDIARIES
                      CONDENSED CONSOLIDATED BALANCE SHEET
                        (In thousands, except share data)
                                   (Unaudited)


<TABLE>
<CAPTION>
                                                       MARCH 31,  December 31,
                                                         1998        1997
                                                       ---------  ------------
<S>                                                    <C>          <C>    
ASSETS 

Current assets
    Cash and cash equivalents                          $ 5,826      $ 5,819
    Accounts receivable                                 17,546       15,043
    Inventories
       Purchased parts                                  11,376       10,523
       Work-in-process                                  11,668       12,833
       Finished products                                 7,013        7,863
                                                       -------      -------
                                                        30,057       31,219

    Prepaid expenses                                       398          363
    Deferred income taxes                                2,648        2,648
    Income tax refund receivable                         1,276        1,321
                                                       -------      -------
            Total current assets                        57,751       56,413

Plant and equipment
    Land                                                 2,040        2,040
    Buildings                                            4,567        4,564
    Equipment                                           19,772       19,306
    Leasehold improvements                               1,013        1,013
                                                       -------      -------
                                                        27,392       26,923

Less accumulated depreciation and amortization          10,742       10,132
                                                       -------      -------
                                                        16,650       16,791
                                                       -------      -------
Excess of purchase price over net assets acquired       11,902       12,126
Other assets                                               387          416
                                                       -------      -------
                                                       $86,690      $85,746
                                                       =======      =======
</TABLE>


            See Notes to Condensed Consolidated Financial Statements


                                       -3-
<PAGE>   4


                           DATUM INC. AND SUBSIDIARIES
                      CONDENSED CONSOLIDATED BALANCE SHEET
                        (In thousands, except share data)
                                   (Unaudited)


<TABLE>
<CAPTION>
                                                   MARCH 31,    December 31,
                                                     1998            1997
                                                   ---------    ------------
<S>                                                <C>            <C>     
LIABILITIES AND STOCKHOLDERS' EQUITY

Current liabilities
    Accounts payable                               $  5,374       $  3,343
    Accrued salaries and wages                        2,421          3,298
    Accrued warranty                                  1,149            990
    Other accrued expenses                            1,406          1,277
    Current portion of long-term debt                 1,519             23
                                                   --------       --------
            Total current liabilities                11,869          8,931
                                                   --------       --------

Long-term debt                                       15,951         17,418
                                                   --------       --------

Postretirement benefits                                 656            602
                                                   --------       --------

Other long-term liabilities                             118            128
                                                   --------       --------

Deferred income taxes                                 1,823          1,823
                                                   --------       --------

Stockholders' equity
    Preferred stock, par value $.25 per share
       Authorized - 1,000,000 shares
       Issued - none                                     --             --
    Common stock, par value $.25 per share
       Authorized - 10,000,000 shares
       Issued - 5,356,093 shares in 1998
                5,332,860 shares in 1997              1,339          1,333
    Additional paid-in                               43,533         43,231
    capital
    Retained earnings
       Beginning of period                           12,785          7,956
       Net income (loss)                               (812)         4,829
                                                   --------       --------
       End of period                                 11,973         12,785

    Cumulative translation adjustment                  (572)          (505)
                                                   --------       --------

            Total stockholders' equity               56,273         56,844
                                                   --------       --------

                                                   $ 86,690       $ 85,746
                                                   ========       ========
</TABLE>


            See Notes to Condensed Consolidated Financial Statements



                                      -4-
<PAGE>   5

                           DATUM INC. AND SUBSIDIARIES
                 CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS
                      (In thousands, except per share data)
                                   (Unaudited)


<TABLE>
<CAPTION>
                                         Three Months Ended
                                              March 31,
                                       -----------------------
                                         1998            1997
                                       --------       --------
<S>                                    <C>            <C>     
Net sales                              $ 25,378       $ 28,724
                                       --------       --------

Costs and expenses
    Cost of goods sold                   17,165         17,394
    Selling                               3,958          3,810
    Product development                   2,798          2,366
    General and administrative            2,370          2,593
    Interest expense                        513            544
    Interest (income)                       (84)            (6)
                                       --------       --------
                                         26,720         26,701
                                       --------       --------

Income (loss) before income taxes        (1,342)         2,023
Income tax provision (benefit)             (530)           829
                                       --------       --------
Net income (loss)                      $   (812)      $  1,194
                                       ========       ========
Net income (loss) per share:
    Basic                              $   (.15)      $    .29
                                       ========       ========
    Diluted                            $   (.15)      $    .26
                                       ========       ========

Shares used in per share calculation:
    Basic                                 5,341          4,119
                                       ========       ========
    Diluted                               5,564          4,534
                                       ========       ========
</TABLE>


            See Notes to Condensed Consolidated Financial Statements



                                      -5-
<PAGE>   6


                           DATUM INC. AND SUBSIDIARIES
                 CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS
                                 (In thousands)
                                   (Unaudited)

<TABLE>
<CAPTION>
                                                                     Three Months Ended
                                                                   -----------------------
                                                                   March 31,     March 31,
                                                                     1998           1997
                                                                   ---------    ----------
<S>                                                                <C>           <C>    
Cash flows from operating activities:
    Net income (loss)                                              $  (812)      $ 1,194
                                                                   -------       -------
    Adjustments to reconcile income (loss) to net cash
       provided by (used in) operating activities:
            Depreciation and amortization                              877           762
            Amortization of goodwill                                   223           223
            Contribution of shares of common stock to
               the Company's 401(k) plan                               185           132
          Changes in assets and liabilities:
            Increase in accounts receivable                         (2,503)       (1,718)
            Decrease in income tax refund receivable                    45            --
            (Increase) decrease in inventories                       1,162        (5,662)
            Increase in prepaid expenses                               (35)          (87)
            Increase in other assets                                    --            (3)
            Increase in accounts payable                             2,031         2,739
            Decrease in accrued expenses                              (590)         (206)
            Increase in income taxes payable                            --           113
            Increase in postretirement benefits                         54            39
            Decrease in other long-term liabilities                    (10)          (10)
                                                                   -------       -------
          Total reconciling items                                    1,439        (3,678)
                                                                   -------       -------
          Net cash provided by (used in) operating activities          627        (2,484)
                                                                   -------       -------
Cash flows from investing activities:
    Book value of equipment disposals                                   --             1
    Capital expenditures                                              (673)         (875)
    Other                                                              (65)         (213)
                                                                   -------       -------
       Net cash used in investing activities                          (738)       (1,087)
                                                                   -------       -------
Cash flows from financing activities:
    Proceeds from (reductions to) long-term debt                        (5)        2,692
    Proceeds from exercise of stock options                             35           259
    Proceeds from ESP plan                                              88            --
                                                                   -------       -------
       Net cash provided by financing activities                       118         2,951
                                                                   -------       -------
Net increase (decrease) in cash and cash equivalents                     7          (620)
Cash and cash equivalents at beginning of period                     5,819         1,389
                                                                   -------       -------

Cash and cash equivalents at end of period                         $ 5,826       $   769
                                                                   =======       =======
</TABLE>


            See Notes to Condensed Consolidated Financial Statements



                                      -6-
<PAGE>   7


                           DATUM INC. AND SUBSIDIARIES

              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

                             MARCH 31, 1998 AND 1997



NOTE A - BASIS OF PRESENTATION

The accompanying unaudited condensed consolidated financial statements have been
prepared in accordance with the requirements of Form 10-Q and, therefore, do not
include all information and footnotes which would be presented were such
financial statements prepared in accordance with generally accepted accounting
principles, and should be read in conjunction with the audited financial
statements presented in the Company's 1997 Annual Report to Stockholders. In the
opinion of management, the accompanying financial statements reflect all
adjustments which are necessary for a fair presentation of the results for the
interim period presented. The results of operations for such interim period are
not necessarily indicative of results to be expected for the full year.

NOTE B - EARNINGS PER SHARE

Effective in the fourth quarter of 1997, the Company adopted Statement of
Financial Accounting Standards No. 128, "Earnings Per Share" (FAS 128). FAS 128
requires dual presentation of net income per share-basic and -diluted. Net
income per share-Basic excludes dilution and is computed by dividing net income
by the weighted average number of common shares outstanding during the reporting
period. Net income per share-Diluted reflects the potential dilution that could
occur if stock options and warrants were exercised. Prior period net income per
share data has been restated to conform with the provisions of this Statement.



                                      -7-
<PAGE>   8


Item 2.  Management's Discussion and Analysis of Financial Condition and 
         Results of Operations.

The following should be read in conjunction with "Management's Discussion and
Analysis of Financial Condition and Results of Operations" presented in the
Company's 1997 Annual Report to Stockholders.

                                INTRODUCTORY NOTE

All statements other than statements of historical fact included in this Report
on Form 10-Q are forward-looking statements within the meaning of Section 27A of
the Securities Act of 1933 and Section 21E of the Securities Exchange Act of
1934 and Datum Inc. ("Datum" or the "Company") intends that such forward-looking
statements be subject to the safe harbors created thereby. Although the Company
believes that the expectations reflected in such forward-looking statements are
reasonable at this time, it can give no assurance that such expectations will
prove to have been correct. The Company makes no undertaking to correct or
update any such statements in the future. Important factors that could cause
actual results to differ materially from the Company's expectations ("Cautionary
Statements") are set forth in "Management's Discussion and Analysis of Financial
Condition or Results of Operations" as well as in the Company's Annual Report on
Form 10-K for the year ended December 31, 1997. All subsequent written and oral
forward-looking statements attributable to the Company or persons acting on its
behalf are expressly qualified in their entirety by the Cautionary Statements.

Overview

Datum designs, manufactures and markets a wide variety of high performance time
and frequency products used to synchronize the flow of information in
telecommunications networks. The Company is also a leading supplier of precise
timing products for enterprise computing networks and a wide variety of space,
scientific and industrial test and measurement applications.

The Company was formed in 1959 and has grown its operations through acquisitions
and internal product development. In 1983, the Company acquired its cesium
standards operation and, in the process, commenced its evolution from a company
primarily supplying timing equipment for military applications to a manufacturer
of a broad range of time and frequency products for telecommunications and other
applications. In 1986, the Company acquired the business that is now enterprise
computing and in 1988, it acquired its current wireline business. In March 1995,
the Company acquired Efratom Time and Frequency Products, Inc. and Efratom
Elektronik GmbH (collectively "Efratom"), the inventor and leading manufacturer
of rubidium oscillators used in cellular and Personal Communications Services
("PCS") networks. In April 1997, the Company acquired the assets of Sigma Tau
Standards Corporation, a leading manufacturer of hydrogen masers, which provide
an extremely stable frequency source over short periods of time in controlled
environments. The Company manufactures each class of time and frequency products
in wide-spread commercial use: hydrogen masers, cesium standards, rubidium
oscillators, quartz oscillators and GPS timing receivers.

The Company serves the markets for high-precision time and frequency devices in
the telecommunications industry which is rapidly expanding as a result of the
conversion of analog to digital systems. The Company also provides extremely
stable cesium standards and GPS receivers that generate and capture time and
frequency for use in wireline telecommunications networks. In addition to
providing time and frequency standards for telecommunications applications, the
Company is a growing supplier of timing products used to ensure the integrity of
information transmitted through enterprise computing networks. The Company also
manufactures frequency sources for satellites, including GPS satellites that
utilize the Company's cesium clocks to provide highly accurate timing and
navigation information throughout the world. Finally, the Company provides time
and frequency products and systems for a wide range of scientific and industrial
test and measurement applications, including missile guidance, geographic
mapping and electric utility operations.

A small number of customers account for a substantial portion of the Company's
net sales and the Company expects that a limited number of customers will
continue to represent a substantial portion of the Company's net sales for the
foreseeable future. There can be no assurance that a major customer will not
reduce, delay or eliminate its purchases from the Company. Any such reduction,
delay or loss in orders could have a material adverse effect on the Company's
business, financial condition and results of operations.



                                      -8-
<PAGE>   9


Results of Operations

The following table sets forth, for the fiscal periods indicated, certain income
and expense items expressed as a percentage of the Company's net sales:

<TABLE>
<CAPTION>
                                                       Percentage of Net Sales
                                     --------------------------------------------------------------
                                     Three Months Ended March 31,          Year Ended December 31,
                                     ----------------------------        --------------------------
                                           1998       1997                1997      1996      1995
                                          ------      ------             ------   -------   -------
<S>                                       <C>         <C>                <C>       <C>       <C>   
Net sales............................     100.0%      100.0%             100.0%    100.0%    100.0%
                                          ------      ------             ------   -------   -------
Costs and expenses
   Cost of goods sold................      67.6%      60.6%               59.8%     61.3%     59.5%
   Selling...........................      15.6%      13.3%               13.9%     13.3%     14.6%
   Product development...............      11.0%       8.2%                9.3%      8.3%     10.5%
   General and administrative........       9.3%       9.0%                8.3%     11.0%     12.6%
   Interest, net.....................       1.7%       1.9%                1.5%      2.5%      2.5%
                                          ------      -----              ------   -------   -------
Income before income taxes...........      (5.3%)      7.0%                7.2%      3.6%      0.3%
Income tax provision.................      (2.1%)      2.9%                2.9%      1.5%      0.2%
                                          ------      -----              ------   -------   -------
Net income...........................      (3.2%)      4.2%                4.2%      2.1%      0.1%
                                          ======      =====              ======   =======   =======
</TABLE>

Net Sales. The Company's net sales are derived primarily from the sale of time
and frequency products for use in telecommunications networks, enterprise
computing networks, satellites and in a variety of other test and measurement
applications. The Company's net sales decreased 11.7% to $25.4 million for the
quarter ended March 31, 1998 from $28.7 million for the corresponding quarter of
1997. The decrease was primarily the result of decreased product usage by the
Company's largest customer during the first two months of 1998. The future
success of the Company depends to a considerable extent upon the continued
growth and increased availability of cellular and other wireless communications
services in the United States and internationally. There can be no assurance
that either subscriber use or the implementation of wireless communications
services will continue to grow, or that such factors will create demand for the
Company's products.

Gross Margin. Gross Margin is derived from net sales and cost of goods sold,
which consist primarily of raw materials, labor, overhead and warranty costs.
Gross margin decreased to 32.4% for the quarter ended March 31, 1998 from 39.4%
for the corresponding quarter of 1997. The decrease in gross margin was
primarily the result of reduced overhead absorption due to lower net sales in
the first two months of 1998. Gross margins can be adversely affected by a
number of other factors, including pricing pressure from the Company's customers
and the difficulty of reducing fixed expenses in connection with the
rescheduling of customers orders.

Selling Expense. Selling expense consists primarily of sales commissions paid to
the Company's third-party representatives and distributors and salaries and
other expenses for its sales and marketing personnel. Selling expense also
includes expenses related to advertising and trade shows. Selling expense
increased by 3.9% to $4.0 million for the quarter ended March 31, 1998, from
$3.8 million for the corresponding quarter of 1997, due to additional marketing
programs. As a percentage of net sales, selling expense increased to 15.6% for
the quarter ended March 31, 1998 from 13.3% for the corresponding quarter of
1997, primarily due to a smaller sales base.

Product Development. Product development expense consists primarily of salary,
applied overhead, materials and third-party design services. Product development
expense increased by 18.3% to $2.8 million for the quarter ended March 31, 1998
from $2.4 million for the corresponding quarter of 1997, primarily due to
increased telecommunication-related development. As a percentage of net sales,
product development expenses increased to 11.0% for the quarter ended March 31,
1998 form 8.2% for the corresponding quarter of 1997. Failure to develop, or
introduce on a timely basis, new products or product enhancements that achieve
market acceptance could materially adversely affect the Company's business,
financial condition and results of operations.

General and Administrative. General and administrative expense consists
primarily of salaries and other expenses for management, finance, accounting and
human resources, as well as amortization of goodwill and depreciation charges.
General and administrative expense decreased 8.6% to $2.4 million for the
quarter ended March 31, 1998, from $2.6 million for the corresponding quarter of
1997, primarily due to the decrease in incentive 




                                      -9-
<PAGE>   10

compensation expense for the quarter ended March 31, 1998, as a result of
reduced earnings. As a percentage of net sales, general and administrative
expense increased to 9.3% for the quarter ended March 31, 1998, from 9.0% for
the corresponding quarter of 1997, due to a smaller sales base.

Interest, Net. Interest expense decreased by $109 thousand to $429 thousand for
the quarter ended March 31, 1998 from $538 thousand for the corresponding
quarter of 1997. The decrease is the result of increased interest earned on the
Company's higher cash balances and the reduction of the Company's debt levels.

Weighted Average Number of Shares Outstanding. The shares outstanding increased
for the quarter ended March 31, 1998 primarily as a result of the Company's
follow-on public offering of 1,035,000 shares of common stock completed April
11, 1997.

Liquidity and Capital Resources

The Company finances its operations primarily through a combination of cash
provided from operations, a commercial bank line of credit and long-term debt.
In addition, on April 11, 1997, the Company completed a follow-on public
offering of 1,035,000 shares of its common stock, raising net proceeds of
approximately $14.2 million.

Cash used in investing activities was approximately $738 thousand for the
quarter ended March 31, 1998 compared to $1.1 million for the corresponding
quarter of 1997 reflecting decreased expenditures for property and equipment.
The Company currently anticipates that capital expenditures for fiscal 1998 will
be approximately $4 million.

Cash provided by financing activities was approximately $118 thousand for the
quarter ended March 31, 1998 compared to $3.0 million for the corresponding
quarter of 1997. The decrease was primarily the result of increased borrowings
in the first quarter of 1997.

Accounts receivable increased to $17.5 million at March 31, 1998 form $15.0
million at December 31, 1997 due to increased shipment levels in the quarter
ended March 31, 1998 compared to the quarter ended December 31, 1997.

Inventories decreased $1.2 million to $30.1 million at March 31, 1998 from $31.2
million at December 31, 1997 due to the Company's continued efforts to manage
inventories to more appropriate levels.

Accounts payable increased by approximately $2.0 million to $5.4 million at
March 31, 1998 from $3.3 at December 31, 1997 as a result of increased inventory
purchases relating to increasing sales volume in the first quarter of 1998.

At March 31, 1998, the Company had working capital of $45.9 million and a
current ratio of 4.9:1 compared to working capital of $47.5 and a current ratio
of 6.3:1 at December 31, 1997. The decrease is due to the reclassification of
$1.5 of long-term debt to current liabilities for payment March 27, 1999. The
Company's long-term debt is provided by The Prudential Insurance Company of
America ("Prudential"). This credit facility consists of: (i) $6.0 million of
Series A senior secured promissory notes to mature September 27, 2000, bearing
interest at the rate of 9.07% on the unpaid principal, payable quarterly, with
the principal re-paid in equal installments of $1.5 million on March 27 and
September 27 of each year, commencing March 27, 1999 and (ii) $12.0 million of
Series B senior secured promissory notes to mature September 27, 2003, bearing
interest at the rate of 10.25% on the unpaid principal, payable quarterly, with
the principal re-paid in equal installments of $2.0 million on March 27 and
September 27 of each year, commencing March 27, 2001. In connection with
entering into this facility, the Company issued to Prudential common stock
warrants for the purchase of 175,000 shares of common stock at an exercise price
per share of $11.50. As of March 31, 1998, none of the warrants had been
exercised.

Under the Company's line of credit with Wells Fargo Bank, the Company has a
two-year revolving line of credit not to exceed the principal amount of $12.0
million, expiring November 1, 1998, bearing interest at the Bank's 




                                      -10-
<PAGE>   11

prime rate or at LIBOR plus 2.25%. The Company is not currently utilizing the
Wells Fargo credit line. The Company expects to renew the line of credit for a
two-year period with Wells Fargo. The Wells Fargo credit facility and the
Prudential credit facility provide the Company with the aggregate borrowing
capacity of $30 million.

Under both agreements, the Company is required to maintain certain financial
ratios, limit other indebtedness and may not pay dividends. Other restrictions
include limitations on the amount of leases and capital expenditures that may be
incurred. The Company currently is in compliance with all such covenants and
restrictions.

The Company has taken actions to understand the nature and extent of the work
required to make its systems products and infrastructure Year 2000 compliant.
Last year, the Company began to prepare its products and review its computer
based systems for the Year 2000, including replacing or updating existing
systems. The Company continues to evaluate the estimated costs associated with
these efforts based on actual experience. While these efforts will involve
additional costs, the Company believes, based on available information, that it
will be able to manage its total Year 2000 transition without any material
adverse effect on its business operations, products or financial condition.

Information Regarding Potential Fluctuations in Quarterly Operating Results

The Company has experienced, and expects to continue to experience, fluctuations
in sales and operating results from quarter to quarter. As a result, the Company
believes that period-to-period comparisons of its operating results are not
necessarily meaningful, and that such comparisons cannot be relied upon as
indicators of future performance. A significant component of the fluctuations
results from rescheduling of orders by the Company's major customers, in some
cases due in part to the customers' attempts to minimize inventories. Other
factors that could cause the Company's sales and operating results to vary
significantly from period to period include: contractual price reductions on
products sold to certain major customers; the time, availability and sale of new
products; changes in the mix of products having differing gross margins;
variations in manufacturing capacities, efficiencies and costs; the availability
and cost of components; warranty expenses; and variations in product development
and other operating expenses. In addition, the sales cycles for many of the
Company's products are often lengthy and unpredictable, and can take up to 36
months. Further, there can be no assurance that the Company will be successful
in closing large transactions on a timely basis or at all. The timing of these
transactions could cause additional variability in the Company's operating
results. The Company's quarterly results of operations are also influenced by
competitive factors, including pricing and availability of the Company's and
competing time and frequency products. A large portion of the Company's expenses
are fixed and difficult to reduce in a short period of time. If net sales do not
meet the Company's expectations, the Company's fixed expenses would exacerbate
the effect of such net sales shortfall. Furthermore, announcements by the
Company or its competitors regarding new products and technologies could cause
customers to defer purchases of the Company's products. Order deferrals by the
Company's customers, purchase policy changes, delays in the Company's
introduction of new products and longer than anticipated sales cycles for the
Company's products have in the past materially adversely affected the Company's
quarterly results of operations. Due to the foregoing factors, as well as other
unanticipated factors, it is likely that in some future quarter the Company's
operating results will be below the expectations of public market analysts or
investors. In such event, the price of the Company's Common Stock would be
materially adversely affected.



                                      -11-
<PAGE>   12


                           PART II. OTHER INFORMATION

Items 1 through 5 have been omitted because the related information is either
inapplicable or has been previously reported.

Item 6. Exhibits and Reports on Form 8-K

(a)     Exhibit No.   Description
        -----------   -----------
           10.42      Employment agreement dated the 27th day of March, 1998
                      with Erik H. van der Kaay

           27.1       Financial Data Schedule


(b) No current reports on Form 8-K were filed during the quarter covered by this
report.



                                      -12-
<PAGE>   13


Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.




DATUM INC.




  /s/ Erik H. van der Kaay                                    Date  May 8, 1998
-------------------------------------- 
Erik H. van der Kaay, President and 
Chief Executive Officer


  /s/ David A. Young                                          Date May 8, 1998
-------------------------------------- 
David A. Young, Chief Financial Officer



                                      -13-
<PAGE>   14

                                  EXHIBIT INDEX


<TABLE>
<CAPTION>
                                                                    Sequentially
                                                                      Numbered
Exhibit No.      Description                                            Page
----------       -----------                                        ------------
<S>            <C>                                                   <C>
  10.42        Employment agreement dated the 27th day of March, 
               1998 with Erik H. van der Kaay

  27.1         Financial Data Schedule
</TABLE>



                                      -14-