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                                                                   Exhibit 10.17


                               UNDERLEASE BETWEEN
                   ROCHDALE INSURANCE COMPANY, UNDERLANDLORD
                                      AND
           BITWISE DESIGNS, INC. AND AUTHENTIDATE, INC., UNDERTENANT

     UNDERLEASE made as of the 19th day of October, 2000, by and between
ROCHDALE INSURANCE COMPANY, a New York corporation, having an office at c/o
AmTrust Realty, 59 Maiden Lane, New York, New York 10038 (hereinafter called
("Underlandlord"), and BITWISE DESIGNS, INC., a Delaware corporation, having an
office at 2165 Technology Drive, Schenectady, New York 12308 ("Bitwise") and
AUTHENTIDATE, INC., a ____________ corporation, having an office at c/o Bitwise
Designs, Inc., 2165 Technology Drive, Schenectady, New York
12308 ("AuthentiDate"; AuthentiDate and Bitwise are collectively, and jointly
and severally "Undertenant").



                              W I T N E S S E T H

     WHEREAS:

     A.  By lease dated April 5, 1990 (such lease as the same has been or may be
amended is hereinafter referred to as the "Main Lease"), Olympia and York Tower
B Lease Company, predecessor-in-interest to Merrill Lynch/WFC/L, Inc., as
landlord ("Overlandlord"), leased to The Yasuda Fire & Marine Insurance Company
of America, as tenant ("Sublandlord"), certain space (the "Leased Space") in the
building known as Two World Financial Center, New York, New York (the
"Building") in accordance with the terms of the Main Lease. A copy of the Main
Lease is annexed hereto as Exhibit A.


     B. By sublease dated as of August 18, 1998, (such sublease as the same has
been or may be amended is hereinafter referred to as the "Sublease"),
Sublandlord subleased to Underlandlord a portion of the Leased Space located on
a portion of the forty-third (43rd) floor of the Building shown hatched on
Exhibit B annexed hereto and made a part hereof (the "Premises") in accordance
with the terms of the Sublease. A copy of the Sublease (from which certain terms
which do not relate to Undertenant's obligations hereunder have been deleted) is
annexed hereto as Exhibit C.

     C. By consent to sublease dated as of October 13, 1998 (the "Consent to
Sublease"), Overlandlord consented to the Sublease, subject to the terms of the
Consent to Sublease. A copy of the Consent to Sublease (from which certain
terms which do not relate to Undertenant's obligations hereunder have been
deleted) is annexed hereto as Exhibit D.

     D. By consent to sub-sublease dated as of October 13, 1998, (the "WFP
Consent"), WFP Tower B Co. L.P. consented to the Sublease, subject to the terms
of the WFP
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Consent. A copy of the WFP Consent (from which certain terms which do not relate
to Undertenant's obligations hereunder have been deleted) is annexed hereto as
Exhibit E.

     E.  Underlandlord and Undertenant desire to consummate an underleasing of
the Subleased Space on terms and conditions contained in this agreement (the
"Underlease").

     NOW, THEREFORE, in consideration of the mutual covenants and agreements
hereinafter contained, it is hereby agreed as follows:

     1.  Term and Rent.

     1.1.  Underlandlord hereby leases to Undertenant and Undertenant hereby
hires from Underlandlord the Premises shown hatched on Exhibit B annexed hereto
and made a part hereof (comprising a portion of the Leased Space) for a term
(the "Underlease Term") to commence on the date Overlandlord and Sublandlord
deliver to Undertenant their consent to this Underlease (the "Underlease
Commencement Date") and to end on March 29, 2006 (the "Underlease Expiration
Date"), or until such term shall sooner cease and terminate as herein provided.
The annual fixed rent to be paid by Undertenant to Underlandlord during the
Underlease Term shall be as follows:

     (i)  TWO HUNDRED SEVENTY EIGHT THOUSAND EIGHT HUNDRED TWENTY-FIVE AND
   00/100 ($278,825.00) DOLLARS per annum during the period commencing on the
   Underlease Commencement Date and ending on the last day of the month in which
   occurs day thirty-three (33) months after of the Underlease Commencement
   Date;

     (ii)  THREE HUNDRED EIGHT THOUSAND ONE HUNDRED SEVENTY FIVE AND 00/100
   ($308,175.00) DOLLARS per annum during the period commencing on the first day
   of the month in which occurs the day thirty-four (34) months after of the
   Underlease Commencement Date and ending on the Underlease Expiration Date.

The fixed annual rent set forth herein shall be paid by Undertenant to
Underlandlord at Underlandlord's office (or such other location as Underlandlord
shall designate) by check drawn on a bank which is a member of the New York
Clearing House Association in equal monthly installments in advance, on the day
which is five (5) business days prior to the first day of each month during the
Underlease Term without any set-off, off-set, abatement or reduction whatsoever,
except that Undertenant shall pay the first monthly installment of annual fixed
rent to Underlandlord upon the execution hereof.



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          2.   Assignment and Subletting.

          2.1  Underlandlord's consent to any further underlease or assignment
proposed by Undertenant shall be given or denied in accordance with the
provisions of Article 7 of the Main Lease as if such provisions were set out
in full herein, provided that if either Overlandlord or Sublandlord shall not
consent to such proposed further underlease or assignment, then Underlandlord
shall have no obligation to give its consent to such further underlease or
assignment, notwithstanding anything to the contrary contained herein.

          3A.  Incorporation of Main Lease.

          3A.1 Except as herein otherwise expressly provided and except for the
obligation to pay rent and additional rent under the Main Lease, all of the
terms, covenants, conditions and provisions in the Main Lease are hereby
incorporated in, and made a part of this Underlease, with the exception of the
"Excluded Main Lease Articles" (as hereinafter defined) (the incorporated
terms, provisions, covenants and conditions are collectively called the
"Incorporated Main Lease Articles") and such rights and obligations as are
contained in the Main Lease are hereby imposed upon the respective parties
hereto; the Underlandlord herein being substituted for the "Landlord" named in
the Main Lease, and the Undertenant herein being substituted for the "Tenant"
named in the Main Lease; provided, however, that the Underlandlord herein shall
not be liable for any defaults by Overlandlord and Underlandlord shall have
all of the rights, but none of the obligations under the Incorporated Main
Lease Articles. If the Main Lease shall be terminated for any reason during the
term hereof, then and in that event this Underlease shall thereupon
automatically terminate, and Underlandlord shall have no liability to
Undertenant by reason thereof unless the termination of the Main Lease was
caused by Underlandlord's default under the Main Lease or Underlandlord's
voluntary agreement to terminate the Main Lease. Upon the termination of this
Underlease, whether by forfeiture, lapse of time or otherwise, or upon the
termination of Undertenant's right to possession, Undertenant will at once
surrender and deliver up the Premises in good condition and repair, reasonable
wear and tear excepted.

          3A.2. For purposes of this Underlease, "Excluded Main Lease Articles"
shall mean the following articles, sections, exhibits and schedules of the Main
Lease: Sections 1.01, 1.02, 1.03, 1.04, 1.05, 2.01, 2.02, 5.04, 5.05, 35.21,
35.23, Articles 3, 11, 14, 28, 29, 33, 36 and 37, Exhibits B-I and B-II, and
Schedules A, B, C-I, C-II, C-III and D and all references in the Main Lease to
the aforesaid Sections, Articles, Exhibits or Schedules of the Main Lease shall
not be deemed incorporated in or made a part hereof. If there are any
provisions in this Underlease that are inconsistent with the Main Lease, the
provisions of this Underlease shall govern unless to do so would result in a
breach of the Main Lease in which case the terms of the Main Lease shall govern.

          3B.  Incorporation of Sublease.

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     3B.1  Except as herein otherwise expressly provided and except for the
obligation to pay rent and additional rent under the Sublease, all of the terms,
covenants, conditions and provisions in the Sublease are hereby incorporated in,
and made a part of this Underlease, with the exception of the "Excluded Sublease
Articles" (as hereinafter defined) (the incorporated terms, provisions,
covenants and conditions are collectively called the "Incorporated Sublease
Articles"), and such rights and obligations as are contained in the Sublease are
hereby imposed upon the respective parties hereto; the Underlandlord herein
being substituted for the "Sublessor" named in the Sublease and the Undertenant
herein being substituted for the "Sublessee" named in the Sublease; provided,
however, that the Underlandlord herein shall not be liable for any defaults by
Sublessor and Underlandlord shall have all of the rights, but none of the
obligations, under the Incorporated Sublease Articles. If the Sublease shall be
terminated for any reason during the term hereof, then and in that event this
Underlease shall thereupon automatically terminate, and Underlandlord shall have
no liability to Undertenant by reason thereof unless such termination was caused
by Underlandlord's default under the Sublease or Underlandlord's voluntary
agreement to terminate the Sublease. Upon the termination of this Underlease,
whether by forfeiture, lapse of time or otherwise, or upon the termination of
Undertenant's right to possession, Undertenant will at once surrender and
deliver up the Premises in good condition and repair, reasonable wear and tear
excepted. Notwithstanding anything to the contrary contained in this Underlease,
Undertenant agrees that Underlandlord may at any time after the date hereof
surrender the Sublease and the premises demised thereunder to Sublandlord,
provided Sublandlord shall deliver a written agreement to Undertenant providing
that notwithstanding such surrender Sublandlord shall not disturb Undertenant's
occupancy of the Premises so long as Undertenant is not in default hereunder if
Undertenant shall at Sublandlord's election either (i) attorn to Sublandlord as
if Sublandlord were the Underlandlord hereunder or (ii) enter into a lease with
Sublandlord for the remaining term of the Underlease on the same terms and
conditions contained herein.

     3B.2. For purposes of this Underlease, "Excluded Sublease Articles" shall
mean the following articles and sections of the Sublease: I, II, IV(a), V(e),
VI, VIII, IX and X and Exhibit B and all references in the Sublease to the
aforesaid Sections or Exhibits of the Sublease shall not be deemed incorporated
in or made a part hereof. If there are any provisions in this Underlease that
are inconsistent with the Sublease, the provisions of this Underlease shall
govern unless to do so would result in a breach of the Sublease in which case
the terms of the Sublease shall govern.

Section IV. (d) of the Sublease is incorporated herein, except as modified by
Section 17 hereof.

     4.    Condition of Premises.

     4.1  Undertenant has examined the Premises, is aware of the physical
condition thereof, and agrees to take the same "as is," in its current
condition and state of repair, with the understanding that there shall be no
obligation on the part of Underlandlord to perform any work,


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supply any materials or incur any expense whatsoever in connection with the
preparation of the Premises for Undertenant's occupancy thereof.

     4.2 (a) Undertenant shall be permitted to use the office furniture and
equipment listed on Exhibit F annexed hereto (the "FF&E") which are currently
located in the Premises and owned by Underlandlord. On the condition that
Undertenant shall not be in default under the Proposed Underlease as of the
Underlease Expiration Date or such earlier date as this Underlease shall expire,
then subject to the final sentence of this Section 4.2(a) hereof, the FF&E shall
become the property of Undertenant at the expiration of the Proposed
Underlease. Underlandlord makes no representations or warranties of any kind
regarding the FF&E, except that the FF&E is free and clear of any liens.
Undertenant has examined the FF&E, is aware of the physical condition thereof,
and agrees to take same "as is" and "where is", in its current condition and
state of repair, with the understanding that there shall be no obligation on the
part of the Underlandlord to perform any work, supply any materials or incur any
expense whatsoever in connection with the preparation of the FF&E for
Undertenant's use thereof. If this Underlease is terminated prior to March 29,
2006 as a result of Undertenant's default, Undertenant shall return the FF&E to
Underlandlord in its current condition and state of repair, subject to
reasonable wear and tear.

         (b) If Undertenant desires to remove any of the FF&E from the Premises
prior to the Underlease Expiration Date, Undertenant shall give Underlandlord a
notice (the "Disposal Notice") specifying which of the FF&E Undertenant desires
to remove from the Premises. Underlandlord shall have the option to remove such
FF&E at Undertenant's sole cost and expense, provided Underlandlord notifies
Undertenant within fifteen (15) business days after Underlandlord's receipt of
the Disposal Notice that Underlandlord is exercising such option. If
Underlandlord does not exercise its option to remove such FF&E at Undertenant's
expenses, then Undertenant shall have the right to remove such FF&E at
Undertenant's sole cost and expense.

     5.  Use.

     5.1 Undertenant agrees that the Premises shall be occupied only as
executive, administrative and general offices for Undertenant's business.

     6.  Consent of Overlandlord and Sublandlord.

     6.1 This Underlease is conditioned upon the consent by Overlandlord and
Sublandlord to this Underlease which consent shall be evidenced by
Overlandlord's and Sublandlord's signature appended hereto or separate consents
in the form utilized by Overlandlord and Sublandlord for such purposes.
Undertenant shall promptly execute any documents reasonably requested by
Overlandlord and/or Sublandlord in order to obtain their approval.

     6.2 Undertenant stipulates that it is familiar with the provisions of
Article 7 of


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the Main Lease. In the event that Overlandlord shall exercise any of its options
pursuant to Sections 7.07, 7.08, 7.09 and 7.10 of the Main Lease with respect to
the Premises upon Underlandlord's request for Overlandlord's consent to this
Underlease, Underlandlord will so notify Undertenant and, upon receipt of such
notification by Underlandlord, this Underlease shall be deemed to be null and
void and without force or effect, and Underlandlord and Undertenant shall have
no further obligations or liabilities to the other with respect to this
Underlease. In the event that Sublandlord shall exercise any of its options
pursuant to Sections 7.07, 7.08, 7.09 and 7.10 of the Main Lease (as
incorporated into the Sublease) with respect to the Premises upon
Underlandlord's request for Sublandlord's consent to this Underlease,
Underlandlord will so notify Undertenant and, upon receipt of such notification
by Underlandlord, this Underlease shall be deemed to be null and void and
without force or effect, and Underlandlord and Undertenant shall have no further
obligations or liabilities to the other with respect to this Underlease.

          6.3.   In the event Overlandlord shall not exercise any of its options
pursuant to Sections 7.07, 7.08, 7.09 and 7.10 of the Main Lease with respect to
the Premises, Underlandlord makes no representation with respect to obtaining
Overlandlord's approval of this Underlease and, in the event that Overlandlord
notifies Underlandlord that Overlandlord will not give such approval,
Underlandlord will so notify Undertenant and, upon receipt of such notification
by Underlandlord of the disapproval by Overlandlord, this Underlease shall be
deemed to be null and void and without force or effect, and Underlandlord and
Undertenant shall have no further obligations or liabilities to the other with
respect to this Underlease.

          6.4.   Except as otherwise specifically provided herein, wherever in
this Underlease Undertenant is required to obtain Underlandlord's consent or
approval, Undertenant understands that Underlandlord may be required to first
obtain the consent or approval of Overlandlord and Sublandlord. If Overlandlord
or Sublandlord should refuse such consent or approval, Underlandlord shall be
released of any obligation to grant its consent or approval whether or not
Overlandlord's or Sublandlord's refusal, in Undertenant's opinion, is arbitrary
or unreasonable. Undertenant agrees that Underlandlord shall not be required to
dispute any determinations or other assertions or claims of Overlandlord or
Sublandlord regarding the obligations of Underlandlord under the Main Lease or
Sublease for which Undertenant is or may be responsible under the terms of this
Underlease. Should Underlandlord elect not to dispute any such determinations,
assertions or claims by Overlandlord or Sublandlord, Underlandlord hereby grants
Undertenant the right to dispute the same in its own name without
Underlandlord's consent and the right to resolve such disputes to its own
satisfaction, provided that (i) Undertenant shall bear any and all costs and
expenses of any such dispute and/or settlement and (ii) Underlandlord shall not
be bound without its consent by any settlement, agreement or resolution reached
by Undertenant and Overlandlord and/or Sublandlord in regard to any such
dispute, or by any decree, judgment or penalty resulting therefrom, and (iii)
Undertenant shall indemnify and hold Underlandlord harmless from and against any
liability, damage, loss, claim or expense (including reasonable attorneys' fees)
incurred by Underlandlord in connection with the exercise of such dispute right.






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     6.5. In the event Sublandlord shall not exercise any of its options
pursuant to Sections 7.07, 7.08, 7.09 and 7.10 of the Main Lease (as
incorporated into the Sublease) with respect to the Premises, Underlandlord
makes no representation with respect to obtaining Sublandlord's approval of this
Underlease and, in the event that Sublandlord notifies Underlandlord that
Sublandlord will not give such approval, Underlandlord will so notify
Undertenant and, upon receipt of such notification by Underlandlord of the
disapproval by Sublandlord, this Underlease shall be deemed to be null and void
and without force or effect, and Underlandlord and Undertenant shall have no
further obligations or liabilities to the other with respect to this Underlease.

     7.   Defaults.

     7.1. Undertenant acknowledges that all services, repairs, restorations,
equipment and access to and for the Premises and any insurance coverage of the
Building will in fact be provided by Overlandlord or Sublandlord, and
Underlandlord shall have no obligation during the term of this Underlease to
provide any such services, repairs, restorations, equipment, access or
insurance. Undertenant agrees to look solely to Overlandlord and/or Sublandlord
for the furnishing of such services, repairs, restorations, equipment, access
and insurance. Underlandlord shall in no event be liable to Undertenant nor
shall the obligations of Undertenant hereunder be impaired or the performance
thereof excused because of any failure or delay on Overlandlord's or
Sublandlord's part in furnishing such services, repairs, restorations,
equipment, access or insurance. If Overlandlord or Sublandlord shall default in
any of their obligations to Underlandlord with respect to the Premises,
Undertenant shall be entitled to participate with Underlandlord in the
enforcement of Underlandlord's rights against Overlandlord or Sublandlord, as
the case may be, but Underlandlord shall have no obligation to bring any action
or proceeding or to take any steps to enforce Underlandlord's right, against
Overlandlord or Sublandlord, as the case may be. If, after written request from
Undertenant, Underlandlord shall fail or refuse to take appropriate action for
the enforcement of Underlandlord's rights against Overlandlord or Sublandlord,
as the case may be, with respect to the Premises within a reasonable period of
time considering the nature of Overlandlord's or Sublandlord's default, as the
case may be, Undertenant shall have the right to take such action in its own
name, and for that purpose and only to such extent, all of the rights of
Underlandlord under the Main Lease or Sublease, as the case may be, hereby are
conferred upon and assigned to Undertenant and Undertenant hereby is subrogated
to such rights to the extent that the same shall apply to the Premises. If any
such action against Overlandlord or Sublandlord, as the case may be, in
Undertenant's name shall be barred by reason of lack of privity,
nonassignability or otherwise, Undertenant may take such action in
Underlandlord's name provided Undertenant has obtained the prior written consent
of Underlandlord, which consent shall not be unreasonably withheld or delayed,
provided, and Undertenant hereby agrees, that Undertenant shall indemnify and
hold Underlandlord harmless from and against all liability, loss, damage or
expense, including, without limitation, reasonable attorney's fees, which
Underlandlord shall suffer or incur by reason of such action.


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<PAGE>   8
          7.2. Anything contained in any provisions of this Underlease to the
contrary notwithstanding, Undertenant agrees, with respect to the Premises, to
comply with and remedy any default claimed by Overlandlord or Sublandlord and
caused by Undertenant, within the period allowed to Underlandlord as subtenant
under the Sublease, and allowed to Sublandlord as tenant under the Main Lease,
even if such time period is shorter than the period otherwise allowed in the
Main Lease due to the fact that notice of default from Underlandlord to
Undertenant is given after the corresponding notice of default from
Overlandlord or Sublandlord, as the case may be. Underlandlord agrees to
forward to Undertenant, upon receipt thereof by Underlandlord, a copy of each
notice of default received by Underlandlord in its capacity as sublessee under
the Sublease. Undertenant agrees to forward to Underlandlord, upon receipt
thereof, copies of any notices received by Undertenant with respect to the
Premises from Overlandlord, Sublandlord or from any governmental authorities.

          7.3  In the event of a default by Underlandlord in the payment of any
sum or performance of any other obligation under the Sublease, Undertenant
shall have the right (but shall not be obligated) to pay such sum directly to
Sublandlord or perform such obligation on behalf of Underlandlord, as the case
may be, and the sums so paid or expended by Undertenant shall be reimbursed to
Undertenant by Underlandlord within twenty (20) days after demand therefor or,
at Undertenant's election, may be offset from the rent and other charges
payable by Undertenant hereunder.

          8.   Underlandlord's Representations.

          8.1  Underlandlord represents (a) that it is the holder of the
interest of the sublessee under the Sublease, and (b) that the Sublease is in
full force and effect.

          9.   Subordination.

          9.1  This Underlease is subject and subordinate to, and Undertenant
accepts this Underlease subject to: (a) the Main Lease, the Sublease, the
Consent to Sublease and the WFP Consent (the "Leasing Documents"), (b) any
amendments and supplements to the Leasing Documents hereafter made, provided
that any such amendment or supplement to the Leasing Documents will not prevent
or adversely affect the use by Undertenant of the Premises in accordance with
the terms of this Underlease, increase the obligations of Undertenant or
decrease its rights under the Underlease or in any other way materially
adversely affect Undertenant, except to a de minimis extent, and (c) all
ground or underlying leases and to all mortgages which may now or hereafter
affect such leases or the real property of which the Premises are a part and
all renewals, modifications, replacements and extensions of any of the
foregoing. This Paragraph 9.1 shall be self-operative and no further instrument
of subordination shall be required. To confirm such subordination, Undertenant
shall execute promptly any certificate that Overlandlord, Sublandlord or
Underlandlord may request.

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          10.  Broker.

          10.1  Undertenant covenants, represents and warrants that Undertenant
has had no dealings or communications with any broker or agent in connection
with the consummation of this Underlease other than Mariner Real Estate
Services, L.L.C., and Newmark & Company Real Estate, Inc. (herein collectively
called the "Broker") and Undertenant covenants and agrees to pay, hold harmless
and indemnify Underlandlord from and against any and all cost, expense
(including reasonable attorneys' fees) or liability for any compensation,
commissions or charges claimed by any broker or agent other than the Broker with
respect to this Underlease or the negotiation thereof.

          10.2  Underlandlord covenants, represents and warrants that
Underlandlord has had no dealings or communications with any broker or agent in
connection with the consummation of this Underlease other than the Broker and
Underlandlord covenants and agrees to pay, hold harmless and indemnify
Undertenant from and against any and all cost, expense (including reasonable
attorneys' fees) or liability for any compensation, commissions or charges
claimed by any broker or agent other than the Broker claiming to have dealt with
Underlandlord with respect to this Underlease or the negotiation thereof.

          11.  Additional Rent.

          11.1  Subtenant stipulates that it is familiar with the provisions of
Section V.(c) of the Sublease and agrees that such provision is incorporated
herein by reference, except that the Base Pilot Amount shall mean the PILOT for
the tax fiscal year July 1, 2000 through June 30, 2001.

          11.2  Subtenant stipulates that it is familiar with the provisions of
Section V.(d) of the Sublease and agrees that such provision is incorporated
herein by reference, except that the Base Operating Year shall mean the
Operating Expenses for the calendar year 2000. Notwithstanding anything to the
contrary contained in this Section 11.2, the additional rent paid pursuant to
this Section 11.2 shall be abated during the period commencing on the Underlease
Commencement Date and ending on June 30, 2001.

          11.3  Undertenant shall pay to Underlandlord any "Tenant Surcharges"
(as that term is hereinafter defined. "Tenant Surcharges" shall mean any and all
amounts other than annual fixed rent, "Operating Expenses" [as such term is
defined in the Main Lease] and the "PILOT" [as such term is defined in the Main
Lease] which, by the terms of the Sublease or Main Lease, become due and
payable by Underlandlord to Sublandlord or to Overlandlord as additional rent or
otherwise and which would not have become due and payable but for the acts,
requests for services, and/or failures to act of Undertenant, its agents,
officers, representatives, employees, servants, contractors, invitees, licensees
or visitors under this Underlease, including, but not limited to: (i) any
increases in Overlandlord's or Sublandlord's fire, rent or other insurance
premiums resulting from any act or omission of Undertenant, (ii) any additional
charges to Underlandlord on account of Undertenant's use of heating,
ventilation, air




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conditioning or electricity after hours or in excess of normal usage, (iii) any
charges which may be imposed on Underlandlord, to the extent that such charges
are attributable to the Premises or the use thereof or services or utilities
provided thereto, and (iv) any additional charges to Undertenant on account of
Undertenant's use of cleaning and elevator services after hours or in excess of
normal usage. Within a reasonable time after receipt by Underlandlord of any
statement or written demand from Overlandlord or Sublandlord including any
Tenant Surcharges, Underlandlord will furnish Undertenant with a copy of such
statement or demand, together with Underlandlord's statement of the amount of
any such Tenant Surcharges, and Undertenant shall pay to Underlandlord the
amount of such Tenant Surcharges within five (5) days after Undertenant's
receipt of such statement or demand; provided, however, that in any instance in
which Undertenant shall receive any such statement or demand directly from
Overlandlord or Sublandlord, Undertenant may pay the amount of the same
directly to Overlandlord or Sublandlord.

     11.4 Payments shall be made pursuant to this Section 11 notwithstanding
the fact that the statement to be provided by Underlandlord is furnished to
Undertenant after the expiration of the term of this Underlease and
notwithstanding the fact that by its terms this Underlease shall have expired
or have been cancelled or terminated.

     12.  Notices.

     12.1 Any notice, demand or communication which, under the terms of this
Underlease or under any statute or municipal regulation must or may be given or
made by the parties hereto, shall be in writing and unless otherwise required
by such law or regulation, shall be sent by (i) hand delivery with receipted
delivery, or (ii) nationally recognized overnight courier service (such as
Federal Express) with receipted delivery, addressed to the party for whom
intended at its address as aforesaid, except that, after the Underlease
Commencement Date, Undertenant's address shall be deemed to be the Building
unless Undertenant shall give notice to the contrary. Either party, however,
may designate such new or other address to which such notices, demands or
communications thereafter shall be given, made or mailed by notice given in the
manner prescribed herein. Any such notice, demand or communication shall be
deemed given or served, as the case may be, on the date of the receipt thereof,
or in the case of refusal to receive, as of the date of such refusal.

     13.  Electricity.

     13.1. Underlandlord shall not be liable in any way to Undertenant for any
failure or defect in the supply or character of electric energy furnished to the
Premises by reason of any requirement, act or omission of the public utility
serving the Building with electricity or for any other reason.

     14.  Alterations.


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          14.1 Undertenant may make no changes, alterations, additions,
improvements or decorations in, to or about the Premises without (x)
Overlandlord's and Sublandlord's prior written consent, which consent shall be
governed by and subject to the relevant provisions of the Main Lease and
Sublease, and (y) Underlandlord's prior written consent, which consent may be
given or denied in Underlandlord's sole discretion, notwithstanding anything to
the contrary in the Main Lease or the Sublease, as incorporated herein.


          15.  Limitation of Liability.

          15.1 Undertenant agrees to look solely to Underlandlord's estate and
interest in this Underlease, and the Premises, for the satisfaction of any right
or remedy of Undertenant for the collection of a judgment (or other judicial
process) requiring the payment of money by Underlandlord, in the event of any
liability by Underlandlord, and no other property or assets of Underlandlord
shall be subject to levy, execution, attachment, or other enforcement procedure
for the satisfaction of Undertenant's remedies under or with respect to this
Underlease, the relationship of Underlandlord and Undertenant hereunder, or
Undertenant's use and occupancy of the Premises, or any other liability of
Underlandlord to Undertenant.

          16. Quiet Enjoyment.

          16.1 So long as Undertenant pays all of the rent and additional rent
due under this Underlease and performs all of Undertenant's other obligations
hereunder, Underlandlord shall not disturb or terminate Undertenant's leasehold
estate hereunder, subject, however, to the terms, provisions and obligations of
this Underlease, the Sublease and the Main Lease.

          16.2 In the event Undertenant does not completely vacate the Premises
by the Underlease Expiration Date or earlier termination of this Underlease,
Undertenant shall defend indemnify and hold harmless Underlandlord in respect
of any and all holdover charges or penalties imposed under the Main Lease or the
Sublease upon Underlandlord in respect of the Premises and in respect of any and
all reasonable costs, liabilities or expenses (including reasonable attorneys
fees) suffered by Underlandlord in respect of same, as and when such costs,
liabilities or expenses are incurred.

          17. Security.

          The amount of security required pursuant to the provisions of the
first paragraph of Section IV. (d) of the Sublease, as incorporated herein,
shall be $250,000 (the "Security Deposit"). The second paragraph of Section IV.
(d) is not incorporated herein. Notwithstanding anything to the contrary
contained in such Section of the Sublease, the Security Deposit shall consist of
the following: (a) 25,000 shares of Bitwise Designs, Inc. stock to be held in
escrow by DiGioia and Goldstein, LLC in the name of AmTrust Financial Services,
Inc., and (b) a letter of credit in the amount necessary to bring the total
value of the Security Deposit to $250,000. The letter of credit shall be issued
by a New York bank satisfactory to Underlandlord and in a form



                                       11

<PAGE>   12
satisfactory to Underlandlord, both in Underlandlord's sole discretion. The
value of the letter of credit shall be adjusted within 15 days after the last
day of each calendar quarter so that on the date 15 days following the last of
each calendar quarter the value of the total security deposit shall equal at
least $250,000 as of the last date of each calendar quarter, with said security
deposit calculation based on the closing price of Bitwise Designs, Inc. common
stock (BTWS-Nasdaq) on the last trading day of such calendar quarter.

          18.   Miscellaneous.

          18.1. This Underlease may not be changed orally, but only by an
agreement in writing signed by the party against whom enforcement of any waiver,
change, modification or discharge is sought.

          18.2. This Underlease shall not be binding upon Underlandlord unless
and until it is signed by Underlandlord and a fully-executed counterpart thereof
has been delivered to Undertenant and approved by Overlandlord and Sublandlord.
This Section 18.2 shall not be deemed to modify the provisions of Article 6
hereof.

          18.3. This Underlease constitutes the entire agreement between the
parties and all representations and understandings have been merged herein.

          18.4. This Underlease shall inure to the benefit of all of the parties
hereto, their successors and (subject to the provisions hereof) their assigns.

          18.5. The term "Underlandlord" as used in this Underlease shall mean
only the Underlandlord named herein, so that in the event of any assignment of
the Sublease, the Underlandlord named herein shall be and hereby is entirely
freed and relieved of all future covenants, obligations and liabilities of
Underlandlord hereunder, including but not limited to covenants, obligations and
liabilities pertaining to Undertenant's security deposit, and it shall be deemed
and construed without further agreement between the parties or their successors
in interest that the assignee of the Sublease has assumed and agreed to carry
out any and all such covenants, obligations and liabilities of Underlandlord
hereunder.

          18.6. Where applicable, Undertenant shall be responsible for all
additional costs incurred as a result of the Underlease, including without
limitation, security cards and keys.

          18.7. Bitwise and AuthentiDate are jointly and severally liable for
all obligations of Undertenant.

          18.8. This Sublease may be executed in multiple counterparts, each of
which shall, when executed, be deemed to be an original, and all of which when
taken together shall constitute but one Sublease. Each party may rely upon a
faxed counterpart of this Sublease executed and delivered by the other party as
if such counterpart were an original counterpart.



                                       12

<PAGE>   13
     IN WITNESS WHEREOF, the parties have hereunto set their hands and seals as
of the day and year first above written.



                                        ROCHDALE INSURANCE COMPANY,
                                        Underlandlord



                                        By: /s/ B. Zyskind
                                           ---------------------------
                                           Name: B. Zyskind
                                           Title: Vice President



                                        BITWISE DESIGNS, INC., Undertenant



                                        By: /s/ Ira C. Whitman
                                           ---------------------------
                                           Name: Ira C. Whitman
                                           Title: Secretary/Vice President



                                        AUTHENTIDATE, INC., Undertenant


                                        By: /s/ Robert Van Naarden
                                           ---------------------------
                                           Name: Robert Van Naarden
                                           Title: CEO/President



                                        THE YASUDA FIRE & MARINE
                                        INSURANCE COMPANY OF AMERICA,
                                        Sublandlord



                                        By:
                                           ----------------------------
                                           Name:
                                           Title:



                                        MERRILL LYNCH/WFC/L, Inc.,
                                        Overlandlord



                                        By:
                                           ---------------------------
                                           Name:
                                           Title:


                                       13
<PAGE>   14
                      BITWISE DESIGNS, INC. ACKNOWLEDGMENT

State of New York        )
                         ):ss
County of Schenectady    )

On the 19th day of October in the year 2000, before me, the undersigned, a
Notary Public in and for said state, personally appeared Ira C. Whitman
personally known to me or proved to me on the basis or satisfactory evidence to
be the person whose name is subscribed to the within instrument and acknowledged
to me that he executed the same in his capacity, and that by his signature on
the instrument, the person, or the entity upon behalf of which the person acted,
executed the instrument, and that such individual made such appearance before
the undersigned in the offices of BitWise Designs, Inc., 2165 Technology Dr.,
Schenectady, NY.



                                        /s/ Elizabeth L. Flatly
                                        Notary Public State of New York
                                        Comm. exp. 10/13/02




                       AUTHENTIDATE, INC. ACKNOWLEDGMENT

State of _____________________     )
                                   ):ss
County of ____________________     )

On the ______ day of ____________ in the year 2000, before me, the undersigned,
a Notary Public in and for said state, personally appeared ________________
personally known to me or proved to me on the basis or satisfactory evidence to
be the person(s) whose name(s) is (are) subscribed to the within instrument and
acknowledged to me that he/she/they executed the same in his/her/their
capacity(ies), and that by his/her/their signature(s) on the instrument, the
person(s), or the entity upon behalf of which the person(s) acted, executed the
instrument, and that such individual made such appearance before the
undersigned in the _________________________________________________
____________________________________________________________________.

                                        ______________________________________
                                                    Notary Public
<PAGE>   15


                      BITWISE DESIGNS, INC. ACKNOWLEDGMENT



State of ___________________________    )
                                        ):ss
County of __________________________    )


On the ___ day of _________ in the year 2000, before me, the undersigned, a
Notary Public in and for said state, personally appeared __________________
personally known to me or proved to me on the basis or satisfactory evidence to
be the person(s) whose name(s) is (are) subscribed to the within instrument and
acknowledged to me that he/she/they executed the same in his/her/their
capacity(ies), and that by his/her/their signature(s) on the instrument, the
person(s), or the entity upon behalf of which the person(s) acted, executed the
instrument, and that such individual made such appearance before the
undersigned in the ____________________________________________________________
____________________________________________________________.



                        _______________________________
                            Notary Public State of





                       AUTHENTIDATE, INC. ACKNOWLEDGMENT

State of New York                       )
                                        ):ss
County of New York                      )


On the 19th day of October in the year 2000, before me, the undersigned, a
Notary Public in and for said state, personally appeared Robert Van Naarden
personally known to me or proved to me on the basis or satisfactory evidence to
be the person(s) whose name(s) is (are) subscribed to the within instrument and
acknowledged to me that he/she/they executed the same in his/her/their
capacity(ies), and that by his/her/their signature(s) on the instrument, the
person(s), or the entity upon behalf of which the person(s) acted, executed the
instrument, and that such individual made such appearance before the undersigned
in the _________________________________________________________________________
____________________________________________________________.



                             /s/ Victor J. Di Gioia
                           _________________________
                                 Notary Public


     VICTOR J. DI GIOIA
Notary Public, State of New York
     No. 31-02014764350
 Qualified in New York County
Commission Expires June 30, 2002