<PAGE>
                                                                     EXHIBIT 4.3


                          CREDIT ENHANCEMENT AGREEMENT

                                      AMONG

                         U.S. BANK NATIONAL ASSOCIATION

                                   AS TRUSTEE,

                                  DISCOVER BANK

                     AS MASTER SERVICER, SERVICER AND SELLER

                                       AND

                   DISCOVER RECEIVABLES FINANCING CORPORATION

                         AS CREDIT ENHANCEMENT PROVIDER

                                 ---------------

                          DATED AS OF DECEMBER 30, 2003

                                 ---------------

                          DISCOVER CARD MASTER TRUST I

                           SERIES 2003-4, SUBSERIES 2





<PAGE>


                                TABLE OF CONTENTS

<Table>
<Caption>
                                                                                                                 PAGE
                                                                                                                 ----

<S>                  <C>                                                                                         <C>
SECTION 1.           Defined Terms................................................................................3

SECTION 2.           Loan.........................................................................................4

SECTION 3.           Calculation of Amount of Interest Payable on the Loan........................................5

SECTION 4.           Payment of Interest on the Loan..............................................................5

SECTION 5.           Repayment of Principal of the Loan...........................................................5

SECTION 6.           Payments to the Holder of the Seller Certificate and the Master Servicer.....................6

SECTION 7.           Deposits to and Withdrawals from the Credit Enhancement Account..............................7

SECTION 8.           Certain Additional Loans.....................................................................7

SECTION 9.           Limited Obligation; Waiver of Setoff; Obligations Absolute...................................8

SECTION 10.          Investments and Information..................................................................9

SECTION 11.          Servicing Transfer...........................................................................9

SECTION 12.          Representations and Warranties...............................................................9

SECTION 13.          Covenants...................................................................................10

SECTION 14.          Governing Law...............................................................................11

SECTION 15.          Termination.................................................................................11

SECTION 16.          Notices.....................................................................................11

SECTION 17.          Bankruptcy..................................................................................12

SECTION 18.          Limitation of Remedies......................................................................12

SECTION 19.          No Petition.................................................................................12

SECTION 20.          Amendments..................................................................................13

SECTION 21.          Successors and Assigns; Replacement of Credit Enhancement Provider..........................13

SECTION 22.          Participation...............................................................................13
</Table>


                                       2
<PAGE>


                  CREDIT ENHANCEMENT AGREEMENT, dated as of December 30, 2003,
among U.S. BANK NATIONAL ASSOCIATION (formerly First Bank National Association,
successor trustee to Bank of America Illinois, formerly Continental Bank,
National Association) as trustee (together with its successors and assigns as
trustee, the "Trustee") for Discover Card Master Trust I (the "Trust"), DISCOVER
BANK (formerly Greenwood Trust Company) ("Discover Bank") as Master Servicer,
Servicer and Seller with respect to the Trust and DISCOVER RECEIVABLES FINANCING
CORPORATION as cash collateral depositor (the "Credit Enhancement Provider").

                                   WITNESSETH

                  WHEREAS, Discover Bank as Master Servicer, Servicer and Seller
and the Trustee have entered into a Pooling and Servicing Agreement, dated as of
October 1, 1993 (as the same may from time to time be amended, modified or
otherwise supplemented, the "Pooling and Servicing Agreement"), and that certain
Series Supplement, dated as of December 30, 2003 (as the same may from time to
time be amended, modified or otherwise supplemented, the "Series Supplement");

                  WHEREAS, the Trust, pursuant to the Pooling and Servicing
Agreement and the Series Supplement, is issuing $789,474,000 in aggregate
principal amount of Investor Certificates of Discover Card Master Trust I,
Series 2003-4, Subseries 2 (the "Series"), which will entitle the holders
thereof to interest during the Revolving Period, the Accumulation Period, and
the Amortization Period, if any, and principal on the Class A Expected Final
Payment Date, the Class B Expected Final Payment Date and during the
Amortization Period, if any;

                  WHEREAS, the principal and interest payments on the Investor
Certificates are to be funded by Principal Collections and Finance Charge
Collections received by the Trust on the Receivables; and

                  WHEREAS, it is a condition to the issuance of the Investor
Certificates that at the closing on the date hereof, the Credit Enhancement
Provider make a term loan (the "Loan") to the Trust, for the benefit of the
Investor Certificateholders of the Series, of $59,210,550 (7.5% of the Series
Initial Investor Interest), for deposit in the Credit Enhancement Account to
provide additional funds to make payments on the Investor Certificates under
certain circumstances.

                  NOW, THEREFORE, in consideration of the mutual covenants
herein contained, and other good and valuable consideration, the receipt and
adequacy of which are hereby expressly acknowledged, the parties hereto agree as
follows:

                  SECTION 1. DEFINED TERMS.

                  (a) The capitalized terms used herein and not otherwise
defined herein shall have the meanings assigned to them in the Pooling and
Servicing Agreement or the Series Supplement, as applicable; provided, however,
that such defined terms shall only have the meanings applicable to Subseries 2
of Series 2003-4.

                  (b) The following terms have the definitions set forth below:




                                       3
<PAGE>

                  "Interest Period" means (i) with respect to the initial
Distribution Date, the period commencing on the Series Closing Date and ending
on the day immediately preceding the initial Distribution Date and (ii) with
respect to each subsequent Distribution Date, the period commencing on the
preceding Distribution Date and ending on the day immediately preceding such
Distribution Date.

                  "Lender Rate" means, with respect to each Interest Period, the
prime commercial lending rate per annum established by the Trustee, as in effect
on each day in the Interest Period.

                  "LIBOR-Based Rate" means, with respect to each Interest
Period, the per annum interest rate equal to the London Interbank Offered Rate
which appears on Telerate Page 3750 at approximately 11:00 a.m. (London time)
two LIBOR Business Days prior to the first day of such Interest Period for
deposits of United States dollars for a period of time comparable to the
Interest Period, and in an amount comparable to the principal amount of the
Loan, plus 0.90%.

                  "Portfolio Yield" means, with respect to any Due Period, the
annualized percentage equivalent of a fraction, the numerator of which shall be
the sum of (i) the amount of Finance Charge Collections received during such Due
Period, (ii) the amount of Series Yield Collections for each Series then
outstanding for such Due Period and (iii) the amount of Series Additional Funds
for each Series then outstanding for such Due Period, and the denominator of
which shall be the total amount of Principal Receivables in the Trust as of the
first day of such Due Period.

                  "Provider Amount" means, with respect to each Distribution
Date, the lesser of (i) the unpaid principal amount of the Loan (including any
amounts loaned by the Credit Enhancement Provider pursuant to Section 8 hereof)
and (ii) the amount on deposit in the Credit Enhancement Account, in each case
before giving effect to any payments, allocations or distributions on such
Distribution Date.

                  "Series Interest Payment Amount" means, for any Distribution
Date, an amount equal to the amount of interest payable on the Loan on such
Distribution Date, including any accrued but unpaid interest with respect to
previous Interest Periods and interest thereon, less the amount paid to the
Credit Enhancement Provider on such Distribution Date pursuant to Section 4(a)
hereof. The Series Interest Payment Amount shall be the amount of interest
payable pursuant to this Agreement for purposes of calculating the "Credit
Enhancement Fee" for the purpose of, and as such term is defined in, the Series
Supplement and such amount shall be paid in accordance with the provisions of
the Series Supplement.

                  SECTION 2. LOAN. The Credit Enhancement Provider hereby makes
a term loan to the Trust, for the benefit of the Investor Certificateholders of
the Series, on the Series Closing Date in an amount equal to $59,210,550,
receipt of which is hereby acknowledged by the Trustee. The amount of such Loan
shall be increased by the amount of any additional loan made by the Credit
Enhancement Provider pursuant to Section 8 hereof.




                                       4
<PAGE>

                  SECTION 3. CALCULATION OF AMOUNT OF INTEREST PAYABLE ON THE
LOAN.

                  (a) The Loan shall bear interest for each day during each
Interest Period with respect thereto at a rate per annum determined for such day
as follows. To the extent the unpaid portion of the principal of the Loan during
such Interest Period equals or is less than the amount on deposit in the Credit
Enhancement Account, the rate for such Interest Period on such principal portion
shall be the LIBOR-Based Rate. To the extent any portion of the unpaid principal
of the Loan exceeds such amount on deposit, the rate for such Interest Period on
such principal portion shall be the Lender Rate.

                  (b) Interest shall be payable monthly in arrears on each
Distribution Date. Interest on the Loan shall be calculated on the basis of the
actual number of days elapsed during the applicable Interest Period divided by
(i) 360, to the extent the LIBOR-Based Rate is applicable, or (ii) 365 or 366,
as the case may be, to the extent the Lender Rate is applicable. The Trustee
shall, as soon as practicable, notify the Seller, the Master Servicer and the
Credit Enhancement Provider of each determination of the Lender Rate and of the
LIBOR-Based Rate. Each determination thereof by the Trustee pursuant to the
provisions of this Agreement shall be conclusive and binding on the Seller, the
Master Servicer and the Credit Enhancement Provider, in the absence of manifest
error.

                  (c) If any portion of interest due and payable on a
Distribution Date is not paid on such Distribution Date, the unpaid portion of
such interest shall be due and payable on the next succeeding Distribution Date.
Any interest that is not paid on the due date thereof shall accrue interest from
the Distribution Date on which such interest was due and payable to the date
such interest is actually paid at a rate per annum equal to the Lender Rate.

                  SECTION 4. PAYMENT OF INTEREST ON THE LOAN. On each
Distribution Date, the Trustee as administrator of the Credit Enhancement shall
pay or cause to be paid to the Credit Enhancement Provider the amount of accrued
but unpaid interest on the Loan from the funds and in the order of priority set
forth below; provided, however, that such payments shall not exceed the amount
of accrued but unpaid interest on the Loan and that such payments will be made
only to the extent such funds are available:

                  (a) interest and earnings (net of losses and investment
expenses) accrued since the preceding Distribution Date on the Provider Amount;
and

                  (b) the Series Interest Payment Amount, to the extent such
amount has been paid to the Trustee as administrator of the Credit Enhancement
pursuant to the Series Supplement.

                  SECTION 5. REPAYMENT OF PRINCIPAL OF THE LOAN. The principal
amount of the Loan shall be due and payable on the Series Termination Date. The
Trust shall repay the unpaid principal balance of the Loan in full on or before
the Series Termination Date in accordance with the provisions of this Agreement;
provided, however, that the unpaid principal amount of the Loan shall only be
paid from the funds described below, and only to the extent such funds are
available.




                                       5
<PAGE>

                  (a) If, as of any Distribution Date, after giving effect to
all other deposits to and withdrawals from the Credit Enhancement Account as of
such Distribution Date, the amount on deposit in the Credit Enhancement Account
exceeds the Total Maximum Credit Enhancement Amount, (i) the amount of such
excess, up to the amount, if any, by which the amount on deposit in the Credit
Enhancement Account exceeds the unpaid principal amount of the Loan, shall be
withdrawn from the Credit Enhancement Account and paid to Discover Bank on
behalf of the Holder of the Seller Certificate and (ii) the remaining amount of
such excess, if any, after payment of any amounts to be paid to Discover Bank on
behalf of the Holder of the Seller Certificate pursuant to clause (i) of this
Section 5(a), shall be withdrawn from the Credit Enhancement Account and paid to
the Credit Enhancement Provider for application toward the unpaid principal
amount of the Loan.

                  (b) On the earlier to occur of (i) the Series Termination Date
and (ii) the day on which the Class Invested Amount with respect to each Class
of the Series is paid in full, and after payment of any amounts to be paid on
such day from the Credit Enhancement Account to or for the benefit of the
Investor Certificateholders of the Series, all amounts remaining on deposit in
the Credit Enhancement Account, up to the amount of the unpaid principal amount
of the Loan, shall be withdrawn from such account and paid to the Credit
Enhancement Provider for application toward the unpaid principal amount of the
Loan.

                  SECTION 6. PAYMENTS TO THE HOLDER OF THE SELLER CERTIFICATE
AND THE MASTER SERVICER.

                  (a) On each Distribution Date, the Trustee as administrator of
the Credit Enhancement shall pay or cause to be paid to Discover Bank on behalf
of the Holder of the Seller Certificate (i) the interest and earnings (net of
losses and investment expenses) accrued since the preceding Distribution Date on
an amount equal to the positive difference, if any, between (x) the amount on
deposit in the Credit Enhancement Account and (y) the Provider Amount and (ii)
the positive difference, if any, between (x) the amount of interest and earnings
(net of losses and investment expenses) accrued since the preceding Distribution
Date on the Provider Amount and (y) the amount paid to the Credit Enhancement
Provider on such Distribution Date pursuant to Section 4(a).

                  (b) On each Distribution Date, an amount equal to the amount,
if any, paid to the Trustee as administrator of the Credit Enhancement pursuant
to Section 9(b)(27) of the Series Supplement, shall be paid to Discover Bank on
behalf of the Holder of the Seller Certificate.

                  (c) On the earlier to occur of (i) the Series Termination Date
and (ii) the day on which the Class Invested Amount with respect to each Class
of the Series is paid in full, and after payment of any amounts to be paid on
such day from the Credit Enhancement Account to or for the benefit of the
Investor Certificateholders of the Series, any amounts remaining on deposit in
the Credit Enhancement Account that are not paid to the Credit Enhancement
Provider pursuant to Section 5(b) hereof shall be withdrawn from such account
and paid to Discover Bank on behalf of the Holder of the Seller Certificate.




                                       6
<PAGE>

                  SECTION 7. DEPOSITS TO AND WITHDRAWALS FROM THE CREDIT
ENHANCEMENT ACCOUNT.

                  (a) The proceeds of the Loan made by the Credit Enhancement
Provider to the Trust pursuant to Section 2 hereof, for the benefit of the
Investor Certificateholders of the Series, on the Series Closing Date and the
proceeds of any additional loan made by the Credit Enhancement Provider pursuant
to Section 8 hereof, shall be deposited into the Credit Enhancement Account. In
addition, any amounts paid to the Trustee as administrator of the Credit
Enhancement on any Distribution Date with respect to the Total Available Credit
Enhancement Amount or the Available Class B Credit Enhancement Amount pursuant
to the terms of the Series Supplement also shall be deposited into the Credit
Enhancement Account upon receipt of such funds by the Trustee.

                  (b) Any withdrawals from the Credit Enhancement Account for
the benefit of the Investor Certificateholders pursuant to Section 9 of the
Series Supplement may be made by the Master Servicer or by the Trustee as
administrator of the Credit Enhancement and shall be deemed to be made first
from amounts on deposit in the Credit Enhancement Account as a result of
payments of Series Excess Servicing and other amounts to the Trustee as
administrator of the Credit Enhancement to fund the Total Available Credit
Enhancement Amount, including any Series Excess Servicing or other such amounts
on deposit in the Credit Enhancement Account as a result of an Alternative
Credit Support Election having been made or as a result of the occurrence of a
Supplemental Credit Enhancement Event, and only after such amounts are exhausted
shall any such withdrawals be deemed to be made from amounts on deposit in the
Credit Enhancement Account that are attributable to the Loan.

                  (c) On or before any Distribution Date on which Discover Bank
is the Master Servicer, all payments made pursuant to this Agreement or the
Series Supplement between the Master Servicer or the Holder of the Seller
Certificate and the Credit Enhancement Account, may be aggregated for such
Distribution Date such that Discover Bank, acting as Master Servicer and as
agent of the Holder of the Seller Certificate, may make only one payment to the
Credit Enhancement Account in satisfaction of all payments of the Master
Servicer and the Holder of the Seller Certificate pursuant to this Agreement or
the Series Supplement, to the extent that all payment obligations of the Master
Servicer and the Holder of the Seller Certificate to the Credit Enhancement
Account on such Distribution Date exceed all payment obligations of the Credit
Enhancement Account to the Master Servicer and the Holder of the Seller
Certificate on such Distribution Date.

                  SECTION 8. CERTAIN ADDITIONAL LOANS.

                  (a) Alternative Credit Support Election. In the event that an
Alternative Credit Support Election is made pursuant to the provisions of the
Series Supplement, Discover Bank on behalf of the Holder of the Seller
Certificate may request that the Credit Enhancement Provider make an additional
loan in the amount of the Additional Credit Support Amount. If Discover Bank on
behalf of the Holder of the Seller Certificate makes such request, and if the
Credit Enhancement Provider elects to make such loan, the amount of such loan
shall be added to the unpaid principal amount of the Loan. In the event that the
Alternative Credit Support Election does not become effective, the Additional
Credit Support Amount (or, if the entire





                                       7
<PAGE>

amount of the Additional Credit Support Amount is not then on deposit in the
Credit Enhancement Account, the portion of the Additional Credit Support Amount
that is then on deposit) shall be withdrawn from the Credit Enhancement Account
and repaid to Discover Bank on behalf of the Holder of the Seller Certificate
(or, if such amount was loaned by the Credit Enhancement Provider, returned to
the Credit Enhancement Provider).

                  (b) Increased Credit Enhancement Amount. In the event the
Series Investor Interest is increased pursuant to Section 32 of the Series
Supplement, requiring an Increased Credit Enhancement Amount, Discover Bank on
behalf of the Holder of the Seller Certificate may request that the Credit
Enhancement Provider make an additional loan in the amount of the Increased
Credit Enhancement Amount. If Discover Bank on behalf of the Holder of the
Seller Certificate makes such request, and if the Credit Enhancement Provider
elects to make such loan, the amount of such loan shall be added to the unpaid
principal amount of the Loan.

                  (c) Supplemental Credit Enhancement Event. In the event that a
Supplemental Credit Enhancement Event occurs, Discover Bank as Servicer may
request that the Credit Enhancement Provider make an additional loan in the
amount of the Supplemental Credit Enhancement Amount. If Discover Bank as
Servicer makes such a request, and if the Credit Enhancement Provider elects to
make such loan, the amount of such loan shall be equal to the Supplemental
Credit Enhancement Amount and shall be added to the unpaid principal amount of
the Loan.

                  (d) Notice. The Credit Enhancement Provider shall give prior
written notice to Moody's of the making of any loan by the Credit Enhancement
Provider other than the additional loans described in this Section 8.

                  (e) Interest Rate. At the time of any additional loan
described in this Section 8, Discover Bank as Servicer and the Credit
Enhancement Provider may agree in writing that the Supplemental Credit
Enhancement Amount, the Increased Credit Enhancement Amount or the Additional
Credit Support Amount, as applicable, shall bear interest at a different
LIBOR-Based Rate, which rate shall reflect prevailing market conditions and the
expected duration of such additional loan.

                  SECTION 9. LIMITED OBLIGATION; WAIVER OF SETOFF; OBLIGATIONS
ABSOLUTE.

                  (a) Notwithstanding any provision in any other section of this
Agreement to the contrary, the obligation to repay the Loan, together with
interest thereon, shall be without recourse to any Seller, the Master Servicer,
any Servicer, the Trustee, the Trust, any Certificateholder, or any affiliate,
officer, director, employee or person acting on behalf of any of them, and the
obligation to pay such amounts shall be limited solely to the application of
funds pursuant to this Agreement, in the manner and to the extent such funds are
available, except for the direct recourse indemnification obligation of each
successor Master Servicer pursuant to Section 11 hereof. The Credit Enhancement
Provider agrees that its interest in funds on deposit in the Credit Enhancement
Account is subordinated to the interests of the Investor Certificateholders of
the Series, as provided in this Agreement and in the Series Supplement. The
Credit Enhancement Provider further agrees that it shall have no right of setoff
or lender's lien



                                       8
<PAGE>
against any Seller, the Master Servicer, any Servicer, the Trustee, the Trust,
or any Certificateholder.

                  (b) The obligations of the Seller, the Trustee, the Credit
Enhancement Provider and the Master Servicer under this Agreement shall be
absolute, unconditional and irrevocable, and shall be performed strictly in
accordance with the terms of this Agreement.

                  SECTION 10. INVESTMENTS AND INFORMATION.

                  (a) The Trustee shall from time to time during the term of
this Agreement invest all amounts on deposit in the Credit Enhancement Account
as the Master Servicer shall direct, which investments shall at all times be
made in compliance with the terms of the Pooling and Servicing Agreement and the
Series Supplement.

                  (b) The Master Servicer shall provide the Credit Enhancement
Provider with such background information and data with respect to the Credit
Enhancement Account as the Credit Enhancement Provider may reasonably request.

                  SECTION 11. SERVICING TRANSFER. In the event that a successor
Master Servicer is appointed pursuant to the Pooling and Servicing Agreement,
from and after the effective date of such transfer of servicing, the successor
Master Servicer appointed pursuant to the Pooling and Servicing Agreement, and
not the former Master Servicer, shall (a) be responsible for the performance of
all servicing functions to be performed from and after such date, (b) agree to
be bound by the terms, covenants and conditions contained herein applicable to
the Master Servicer and be subject to the duties and obligations of the Master
Servicer hereunder, and (c) agree to indemnify and hold harmless the Credit
Enhancement Provider from and against any and all claims, damages, losses,
liabilities, costs or expenses whatsoever which the Credit Enhancement Provider
may incur (or which may be claimed against the Credit Enhancement Provider) by
reason of the gross negligence or willful misconduct of the successor Master
Servicer in exercising its powers and carrying out its obligations under the
Pooling and Servicing Agreement and the Series Supplement. Such transfer of
servicing shall not affect any rights or obligations of the former Master
Servicer under this Agreement that arose prior to the effective date of the
transfer of servicing, except that such former Master Servicer shall have no
obligation to indemnify the Credit Enhancement Provider as a result of any act
or failure to act of any successor Master Servicer in the performance of the
servicing functions.

                  SECTION 12. REPRESENTATIONS AND WARRANTIES.

                  (a) The Credit Enhancement Provider hereby represents and
warrants to the Master Servicer and the Trustee that:

                  (i) The Credit Enhancement Provider has been duly incorporated
and is validly existing as a corporation in good standing under the laws of the
State of Delaware, and has the corporate power and authority to execute, deliver
and perform its obligations under this Agreement.

                  (ii) This Agreement has been duly authorized, executed and
delivered on the part of the Credit Enhancement Provider.




                                       9
<PAGE>

                  (iii) When executed and delivered, this Agreement will
constitute a valid and binding agreement of the Credit Enhancement Provider
enforceable against the Credit Enhancement Provider in accordance with its
terms, except (A) as the same may be limited by insolvency, bankruptcy or
reorganization or other laws relating to or affecting the enforcement of
creditors' rights and (B) as the same may be limited by general equity
principles (whether considered in a proceeding at law or in equity) and by the
discretion of the court before which any proceeding therefor may be brought.

                  (b) The Master Servicer hereby represents and warrants to the
Credit Enhancement Provider and the Trustee that:

                  (i) The Master Servicer has been duly incorporated and is
validly existing as a banking corporation in good standing under the laws of the
State of Delaware, and has the corporate power and authority to execute, deliver
and perform its obligations under the Pooling and Servicing Agreement, the
Series Supplement and this Agreement.

                  (ii) This Agreement, the Pooling and Servicing Agreement and
the Series Supplement have been duly authorized, executed and delivered on the
part of the Master Servicer.

                  (iii) When executed and delivered, each of this Agreement, the
Pooling and Servicing Agreement and the Series Supplement will constitute a
valid and binding agreement of the Master Servicer enforceable against the
Master Servicer in accordance with its terms, except (A) as the same may be
limited by insolvency, bankruptcy, receivership or reorganization or other laws
relating to or affecting the enforcement of creditors' rights and (B) as the
same may be limited by general equity principles (whether considered in a
proceeding at law or in equity) and by the discretion of the court before which
any proceeding therefor may be brought.

                  (c) The Trustee hereby represents and warrants to the Credit
Enhancement Provider and the Master Servicer that:

                  (i) The Trustee is organized, existing and in good standing
under the laws of the United States of America.

                  (ii) The Trustee has full power, authority and right to
execute, deliver and perform this Agreement, the Pooling and Servicing Agreement
and the Series Supplement, and has taken all necessary action to authorize the
execution, delivery and performance by it of this Agreement, the Pooling and
Servicing Agreement and the Series Supplement.

                  (iii) Each of this Agreement, the Pooling and Servicing
Agreement and the Series Supplement have been duly executed and delivered by the
Trustee.

                  SECTION 13. COVENANTS. Discover Bank, as Master Servicer and
on behalf of the Holder of the Seller Certificate, covenants and agrees that, so
long as this Agreement shall remain in effect or any monetary obligation arising
hereunder or under the Series Supplement shall remain unpaid, it will change the
terms and provisions of a Credit Agreement with respect to a Discover Bank
Discover Card Account or any other Account with respect to which it is the
Servicer (including, without limitation, the calculation of the amount, or





                                       10
<PAGE>

the timing, of charge-offs) only if it does not believe, after a good faith
assessment of the expected effects of such change, that such change will result
in a reduction of the Portfolio Yield, for any Due Period beginning prior to the
termination of the Series, to less than the Base Rate unless such change (i) is
required by any Requirements of Law or (ii) is deemed necessary by Discover Bank
in its sole reasonable judgment to maintain its credit card business on a
competitive basis. For purposes of this Section 13, "Base Rate" shall mean (i)
the weighted average of the Certificate Rates for each Class of each Series then
outstanding plus (ii) 1% per annum. For purposes of the immediately preceding
sentence, the Certificate Rate for each Class that does not have a fixed
Certificate Rate shall be the actual Certificate Rate for such Class for the
Interest Accrual Period commencing in the immediately preceding Due Period. In
the event that any Additional Seller shall transfer Receivables in Additional
Accounts to the Trust, Discover Bank on behalf of the Holder of the Seller
Certificate shall cause the Servicer with respect to such Additional Accounts to
make the covenant set forth above with respect to such Additional Accounts.

                  SECTION 14. GOVERNING LAW. THIS AGREEMENT SHALL BE CONSTRUED
IN ACCORDANCE WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK, WITHOUT REFERENCE
TO ITS CONFLICT OF LAW PROVISIONS, AND THE OBLIGATIONS, RIGHTS AND REMEDIES OF
THE PARTIES HEREUNDER SHALL BE DETERMINED IN ACCORDANCE WITH SUCH LAWS.

                  SECTION 15. TERMINATION. This Agreement shall terminate on the
date on which the Series terminates in accordance with the provisions of the
Pooling and Servicing Agreement and the Series Supplement; provided, however,
that this Agreement may be terminated by the Master Servicer at any time,
without penalty, provided that such termination does not cause the ratings of
the Investor Certificates to be lowered or withdrawn by either of the Rating
Agencies; and provided, further, that all amounts owing to the Credit
Enhancement Provider hereunder with respect to principal and interest on the
Loan shall have been paid in full. Notwithstanding the foregoing, the Credit
Enhancement Provider shall have no rights under this Agreement, and shall not be
entitled to any payments hereunder, if and for so long as there is no Loan
outstanding hereunder and no accrued but unpaid interest.

                  SECTION 16. NOTICES. Unless specifically indicated otherwise
herein, all notices and other communications provided for hereunder shall be in
writing and, if to the Credit Enhancement Provider, addressed to:

                   Discover Receivables Financing Corporation
                                  12 Read's Way
                           New Castle, Delaware 19720
                  Attn: Executive Vice President and Secretary
                              Phone: (302) 323-7167
                               Fax: (302) 323-7393

or, if to the Seller or the Master Servicer, addressed to:

                                  Discover Bank
                                  12 Read's Way




                                       11
<PAGE>
                           New Castle, Delaware 19720
                            Attn: Michael F. Rickert
                              Phone: (302) 323-7434
                               Fax: (302) 323-7393

or, if to the Trustee, addressed to:

                         U.S. Bank National Association
                                Wrigley Building
                      400 North Michigan Avenue, 2nd Floor
                                    ILWB0410
                          Chicago, Illinois 60611-4181
                             Attn: Patricia M. Child
                              Phone: (312) 836-6713
                               Fax: (312) 836-6701

or as to any party at such other address as shall be designated by such party in
a written notice to the other parties.

                  Any notice or other communication shall be sufficiently given
and shall be deemed given when delivered to the addressee in writing or when
transmitted by telecopier, receipt of which by the addressee is confirmed by
telephone.

                  SECTION 17. BANKRUPTCY. To the extent that the Trustee, the
Master Servicer or Discover Bank on behalf of the Holder of the Seller
Certificate makes a payment to the Credit Enhancement Provider or the Credit
Enhancement Provider receives any payment or proceeds with respect to the Loan,
which payment or proceeds or any part thereof are subsequently invalidated,
declared to be fraudulent or preferential, set aside or required to be repaid to
a trustee, receiver or any other party under any state or federal insolvency or
bankruptcy law then, to the extent such payment or proceeds are set aside, the
amount or part thereof intended to be satisfied shall be revived and continue in
full force and effect, as if such payment or proceeds had not been received by
the Credit Enhancement Provider.

                  SECTION 18. LIMITATION OF REMEDIES. The Credit Enhancement
Provider shall not have the right to cause the Loan or any portion thereof to
become due and payable prior to the due date for the Loan as set forth herein.

                  SECTION 19. NO PETITION.

                  (a) The Credit Enhancement Provider, by entering into this
Agreement, hereby covenants and agrees that it will not at any time institute,
join in or otherwise cause the institution of, against any Seller, the Master
Servicer or the Trust, any bankruptcy, reorganization, arrangement, insolvency
or liquidation proceedings, or other proceedings under any United States federal
or state or similar law prior to a year and a day after the final payment of all
investor certificates issued by any trust with respect to which Discover Bank is
the seller.

                  (b) Each of Discover Bank and the Trustee, by entering into
this Agreement, hereby covenants and agrees that it will not at any time
institute, join in or otherwise cause the






                                       12
<PAGE>

institution of, against the Credit Enhancement Provider, any bankruptcy,
reorganization, arrangement, insolvency or liquidation proceedings, or other
proceedings under any United States federal or state or similar law prior to a
year and a day after the final payment of all investor certificates issued by
any trust with respect to which Discover Bank is the seller.

                  SECTION 20. AMENDMENTS. This Agreement shall not be amended or
modified without the written consent of each of the parties hereto. No amendment
hereto shall become effective without prior confirmation from the Rating
Agencies that such amendment will not cause a lowering or withdrawal of the then
current ratings of the Investor Certificates of the Series. The Master Servicer
shall provide a copy of any amendment hereto to the Rating Agencies.

                  SECTION 21. SUCCESSORS AND ASSIGNS; REPLACEMENT OF CREDIT
ENHANCEMENT PROVIDER.

                  (a) This Agreement shall be binding upon, and inure to the
benefit of, the Trustee, the Sellers, the Servicers, the Master Servicer and the
Credit Enhancement Provider and their respective successors and permitted
assigns.

                  (b) No Seller shall assign its interests hereunder and under
the Pooling and Servicing Agreement or the Series Supplement, or any portion of
such interests, except by an assignment that transfers each such interest to the
same assignee.

                  (c) In the event that a successor trustee is appointed
pursuant to the provisions of the Pooling and Servicing Agreement to replace the
then current Trustee, such successor trustee, from and after its appointment,
shall be the Trustee for purposes of this Agreement and shall assume all of the
rights and obligations of the Trustee hereunder.

                  (d) The Credit Enhancement Provider may not assign any of its
rights or obligations hereunder without the prior written consent of Discover
Bank on behalf of the Holder of the Seller Certificate and without prior written
confirmation from the Rating Agencies that such assignment will not result in
the lowering or withdrawal of the rating of any Class of any Series then
outstanding.

                  SECTION 22. PARTICIPATION. Any successor Credit Enhancement
Provider that is not a special-purpose corporation that is an affiliate of
Discover Bank may, without the consent of the Trustee, the Trust, any Seller,
the Master Servicer, any Servicer or any Certificateholder of the Series, sell
participations to one or more banks or other entities in all or a portion of its
rights under this Agreement (including all or a portion of the Loan); provided,
however, that (a) the Credit Enhancement Provider's obligations under this
Agreement shall remain unchanged, (b) the Credit Enhancement Provider shall
remain solely responsible to the other parties hereto for the performance of
such obligations, (c) the Trustee, the Trust, the Sellers and the Master
Servicer shall continue to deal solely and directly with the Credit Enhancement
Provider in connection with the Credit Enhancement Provider's rights and
obligations under this Agreement, and (d) the Credit Enhancement Provider shall
retain the sole right to enforce the obligations of the Trustee, the Trust, the
Sellers or the Master Servicer under this Agreement and to approve any
amendment, modification or waiver of any provision of this Agreement.




                                       13
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                  IN WITNESS WHEREOF, the parties hereby have caused this
Agreement to be duly executed and delivered by the undersigned thereunto duly
authorized as of the day and year first above written.

                              DISCOVER RECEIVABLES FINANCING
                              CORPORATION,
                              as Credit Enhancement Provider



                              By:      /s/ Jai Sooklal
                                       -------------------------------
                                       Name:  Jai Sooklal
                                       Title: Vice President



                              DISCOVER BANK,
                              as Master Servicer, Servicer and Seller



                              By:      /s/ Michael F. Rickert
                                       -------------------------------
                                       Name:  Michael F. Rickert
                                       Title: Vice President, Chief Accounting
                                              Officer and Treasurer




                              U.S. BANK NATIONAL ASSOCIATION,
                              as Trustee



                              By:      /s/ Patricia M. Child
                                       -------------------------------
                                       Name:  Patricia M. Child
                                       Title: Vice President




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