Encrypting the (Sub)tree

 <PaymentInfo>

    <Name>Ivan Herman</Name>

    <CreditCard>

       <Name>VISA</Name>

       <Number>4567 8901 2345 5678</Number>

       <Expiration>01 01</Expiration>

    </CreditCard>

 </PaymentInfo>

Can be encrypted as follows:

 <PaymentInfo>

    <Name>Ivan Herman</Name>

    <EncryptedData Type="http://www.w3.org/…/xmlenc#Element"

        xmnls="http://www.w3.org/2001/04/xmlenc#">

       <CipherData><CipherValue>QEK^SD27</CipherValue></CipherData>

    </EncryptedData>

 </PaymentInfo>

An eavesdropper doesn’t knows about any Credit Card!