- From: Magnus Nyström <magnus@rsa.com>
- Date: Mon, 18 May 2009 23:58:30 +0200 (W. Europe Daylight Time)
- To: public-xmlsec@w3.org
All,
This is in response to ACTION-290 that I took during the f2f last week.
When looking at this, the basic requirement would seem to be allowing use
of key encapsulation when transporting encryption keys. A design goal
should probably also be to allow re-use of the existing EncryptedKeyType.
One possibility is to define a new URI "KEM-KTS" (Key Encapsulation Method
- Key Transport Scheme) for use as the "Algorithm" value in
xenc:EncryptionMethod. Then, using the extensibility of the
EncryptionMethodType, one could define a KeyEncapsulationMethodType that
would define the necessary parameters:
- KeyDerivationMethod (re-using what is defined in Derived Key)
- KeyLength (possibly the "KeySize" element of EncryptionMethodType may be
re-used)
- KeyWrapMethod (the algorithm used to wrap the actual content-encryption
key using the derived key)
- Other (extensibility point)
KeyInfo would in the case of RSA contain the recipient's public key
and in the case of ECC, it would contain a value of type AgreementMethod
that in turn would contain the two ECDH params.
Here's a possible schema:
<element name="KeyEncapsulationMethod" type="kem:KeyEncapsulationMethodType"/>
<complexType name="KeyEncapsulationMethodType">
<sequence>
<element ref="dkey:KeyDerivationMethod"/>
<element ref="kem:KeyWrapMethod"/>
<any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</sequence>
<attribute name="Algorithm" type="anyURI" use="required"/>
</complexType>
<element name="KeyWrapMethod" type="kem:KeyWrapMethodType"/>
<complexType name="KeyWrapMethodType">
<sequence>
<any namespace="##other" minOccurs="0" maxOccurs="unbounded"/>
</sequence>
<attribute name="Algorithm" type="anyURI" use="required"/>
</complexType>
Comments?
-- Magnus
Received on Monday, 18 May 2009 21:58:55 UTC