Hi Erikthis is pure guesswork on my part, but if you are using MAC/MLS and the directory response is encrypted, then it has to be encrypted to some public key. In MAC/MLS that key could be the key of the security level/clearance of the associated directory data, as opposed to the public key of the requestor (DUA). Thus the user needs to know which private key to use to decrypt the information, and the AC holds the clearances that are needed. If the user has the clearances, then he will indirectly have the private key needed to decrypt the data.
regards David On 17/07/2011 15:54, Erik Andersen wrote:
Hi David, Probably due to my ignorance, I do not understand what an attribute certificate has to do with signing and encryption of the operation, and it not clear what attribute the paragraph talks about. If I do not understand it, others may be in the same siruation. In addition, the AttributeCertificationPath data type in 12.2 of X.509 is not that easy to understand. Erik Andersen Andersen's L-Service Elsevej 48, DK-3500 Vaerloese Denmark Mobile: +45 2097 1490 e-amail: era@xxxxxxx Skype: andersen-erik http://www.x500.eu/ http://www.x500standard.com/ http://dk.linkedin.com/in/andersenerik -----Oprindelig meddelelse----- Fra: x500standard-bounce@xxxxxxxxxxxxx [mailto:x500standard-bounce@xxxxxxxxxxxxx] På vegne af David Chadwick Sendt: 17. juli 2011 15:01 Til: x500standard@xxxxxxxxxxxxx Emne: [x500standard] Re: Can anyone explain ... (signing of bind)? Hi Erik I think it is a cut and paste error. If you remove "or other attribute, conveyed in an Attribute Certificate," from the last sentence and insert it into the first sentence, it starts to make sense, viz: If the operation is to be signed and encrypted, an attribute certificate containing the attribute certificate or other attribute, conveyed in an Attribute Certificate, may be used to convey the clearances required to access the attribute. The attributeCertificationPath is used to convey a security clearance for rule based access control, optionally with the certificates needed to validate the Attribute Certificate. the reference to X.509 appears to be wrong so I removed it regards David On 17/07/2011 09:55, Erik Andersen wrote:A lot of garbage was introduced in the third edition of the Directory Specifications and we are still struggling with some of the stuff. The following paragraph was introduces at the start of clause 8 or X.511 - Bind operation. “The arguments of the operation may be signed, encrypted, or signed and encrypted (see clause 15.3 of ITU-T Rec. X.501 | ISO/IEC 9594-2) by the requestor. If so requested, the Directory may sign, encrypt, or sign and encrypt the results. (The bit on encryption was later removed).” However, neither the bind argument nor the bind result specifies the possibility for signing. The third edition also introduce signing of bind errors. Does that make sense? The requestor cannot ask for signing of bind error, as the securityParameters are not included in the bind argument. Now the very big question. Can anyone explain the following paragraph introduced in the third edition of 8.1.2 Directory Bind arguments? If the operation is to be signed and encrypted, an attribute certificate containing the attribute certificate (See Clause 8.2 of ITU-T Rec. X.509 | ISO/IEC 9594-8) may be used to convey the clearances required to access the attribute. The***attributeCertificationPath* is used to convey a security clearance for rule based access control, or other attribute, conveyed in an Attribute Certificate, optionally with the certificates needed to validate the Attribute Certificate. Erik Andersen Andersen's L-Service Elsevej 48, DK-3500 Vaerloese Denmark Mobile: +45 2097 1490 e-amail: era@xxxxxxx Skype: andersen-erik http://www.x500.eu/ http://www.x500standard.com/ http://dk.linkedin.com/in/andersenerik
-- ***************************************************************** David W. Chadwick, BSc PhD Professor of Information Systems Security School of Computing, University of Kent, Canterbury, CT2 7NF Skype Name: davidwchadwick Tel: +44 1227 82 3221 Fax +44 1227 762 811 Mobile: +44 77 96 44 7184 Email: D.W.Chadwick@xxxxxxxxxx Home Page: http://www.cs.kent.ac.uk/people/staff/dwc8/index.html Research Web site: http://www.cs.kent.ac.uk/research/groups/iss/index.html Entrust key validation string: MLJ9-DU5T-HV8J PGP Key ID is 0xBC238DE5 ***************************************************************** ----- www.x500standard.com: The central source for information on the X.500 Directory Standard.