IPP> SEC - Security parameters for IPP scheme

IPP> SEC - Security parameters for IPP scheme

IPP> SEC - Security parameters for IPP scheme

Paul Moore paulmo at microsoft.com
Fri Aug 7 14:49:00 EDT 1998


Thats a proposed solution - whats the requirement?

> -----Original Message-----
> From:	Carl-Uno Manros [SMTP:manros at cp10.es.xerox.com]
> Sent:	Friday, August 07, 1998 11:29 AM
> To:	Paul Moore; ipp at pwg.org
> Subject:	RE: IPP> SEC - Security parameters for IPP scheme
> 
> At 11:21 AM 8/7/98 PDT, Paul Moore wrote:
> >What is the requirement from Keith?
> >
> 
> To have security parameters in the ipp scheme, so you know how to map the
> ipp scheme to the underlying layer, in particular how to start off the
> communication with the IPP server if you use TLS.
> 
> Carl-Uno
> 
> 
> >> -----Original Message-----
> >> From:	Carl-Uno Manros [SMTP:manros at cp10.es.xerox.com]
> >> Sent:	Friday, August 07, 1998 10:31 AM
> >> To:	ipp at pwg.org
> >> Subject:	IPP> SEC - Security parameters for IPP scheme
> >> 
> >> All,
> >> 
> >> John Wenn and Daniel Manchala have worked on coming up with a proposal
> on
> >> how to add security paameters to the "ipp" scheme, to meet another
> >> requirement from our Area Director Keith Moore. This text was not
> deemed
> >> suitable for inclusion in the just circulated draft on the Internet
> >> Printing Protocol Scheme, as it has not yet been reviewed in the WG,
> but
> >> you should view this as complementary to scheme draft.
> >> 
> >> I would expect us to discuss this proposal on the DL and in the Toronto
> >> meeting.
> >> 
> >> Carl-Uno      
> >> 
> >> ------
> >> 
> >>         1.0 Introduction
> >> 
> >>         It is required that the Internet Printing Protocol be able to
> >>         operate within a secure environment. Wherever possible, IPP
> >>         ought to make use of existing security protocols and services.
> >>         IPP will not invent new security features when the requirements
> >>         described in this document can be met by existing protocols and
> >>         services. Examples of such services include Secure Sockets
> >>         (SSL) [SSL2, SSL3], Digest Access Authentication in HTTP
> >>         [HTTP], and the Content MD-5[MD5] Header Field in MIME.
> >> 
> >> 
> >> 	IPP [IPP-PRO, IPP-MOD, IPP-REQ] makes use of  the "ipp:" URL
> >> 	scheme with HTTP 1.1 as a transport protocol, in which URL path
> >> 	names and MIME types are used to encode IPP from the HTTP
> >> 	protocol data stream. Security attributes like the mechanism
> >> 	used (TLS[TLS], SSL[SSL2, SSL3], DAA, etc), type and strength
> >> 	of encryption, signature and integrity algorithms used (e.g:
> >> 	RSA - 40 [RSA], MD5[MD5], etc.,) are specified as parameters as
> >> 	part of the ipp URL.
> >> 
> >>         IPP Scheme Syntax and Security Parameters
> >>         ------------------------------------------------------
> >> 
> >> 	The syntax for the IPP [IPP] scheme is identical to the
> >> 	existing "http" scheme except for the scheme name, security
> >> 	attributes and different default port.  This syntax could  also
> >> 	be used for later versions of HTTP [HTTP] protocol that could
> >> 	specify the security attributes as part of the http:// URL.
> >> 
> >>         IPP syntax:
> >> 
> >>         ipp://host[:port]/<IPP-specific-abs-path>/parameters
> >> 
> >>         Parameters can be specified as follows:
> >>         AUTH = secure-protocol [ ":" protocol optional parameters]
> >>         where
> >>         secure-protocol := "TLS" | "SSL3" | "SSL2" | "DAA" 
> >> 
> >>         TLS parameters :=  [ key-exchange "-" strength ";" 
> >>                               encryption-algorithm "-" strength ";" 
> >>                               hash-function "-" strength].
> >> 
> >>         SSL3 parameters := [ key-exchange "-" strength ";" 
> >>                               encryption-algorithm "-" strength ";" 
> >>                               hash-function "-" strength].
> >> 
> >>         DAA parameters := [hash-function "-" strength].
> >> 
> >>         If optional parameters are not supplied, standard default
> >>         parameters will be used.
> >> 
> >>         In the future other protocols like IPV6 could also be used as
> >>         the secure protocol.
> >> 
> >>         key exchange is the specific algorithm used to securely
> >>         exchange public keys between the client and server. The exact
> >>         values are specified by the specific protocol.  For example,
> >>         TLS specifies allowed key exchange values in Appendix C of the
> >>         standard.  Examples of key exchange algorithms include RSA, DH
> >>         and variants.
> >> 
> >>         encryption algorithm is the specific algortithm used to
> >>         achieve confidentiality. Like key exchange, the exact values
> >>         are specified by the specific protocol.  Examples of such
> >>         algorithms include 3DES[3DES], RC4 and IDEA.  Encryption
> >>         algorithm always should be specified with the strength of
> >>         encryption key in bits.
> >> 
> >>         hash-function is the specific algorithm used to perform a
> >>         message digest on the data being sent.  Like key exchange, the
> >>         exact values are specified by the specific protocol.  Example
> >>         of a hash-function could be MD5[MD5]. Strength could be the bit
> >>         value of the resulting hash.
> >> 
> >>         For the case of TLS[TLS] and SSL[SSL2, SSL3], the client
> >>         presents a list of acceptable parameters to the server, and the
> >>         server chooses one among the specified list. In this scheme, if
> >>         a parameter is specified, it is the preferred value for the
> >>         parameter. Other values may be configured. For SSL, the client
> >>         translates the URI into a https URI. For TLS, the client
> >>         translates the URI into a TLS compatible URI. {This
> >>         compatiblity is still not finalized by the TLS standard
> >>         group}.
> >> 
> >>         In the case of DAA[DAA], the URI is used as a security input.
> >>         In this scheme, the translated URI (http method) is used as the
> >>         input.
> >> 
> >> 
> >>         TRANSLATION OF IPP SCHEME INTO HTTP SCHEME.
> >>         ---------------------------------------------------------
> >> 
> >>         Translation of the ipp scheme into http depends upon whether
> >>         proxy servers, tunnels or gateways are used. Parameters are
> >>         translated into header fields in the HTTP protocol. Section 4.5
> >>         of RFC 2068 describes the general header fields used. It is
> >>         proposed to add a security-protocol protocol that corresponds
> >>         to the AUTH parameter of the ipp protocol. In order not to
> >>         confuse with the WWW-Authenticate response header that a server
> >>         sends to the client when it wants to be authenticated, we use
> >>         the general header field security-protocol to specify that the
> >>         client requests a connection of type specified in the
> >>         security-protocol. The AUTH parameter directly translates into
> >>         the HTTP [HTTP] security-protocol header as follows:
> >> 
> >>         security-protocol =   protocol  [
> >>                 ":" encryption-algorithm "-" strength ";" 
> >>                 signature-algorithm "-" strength ";" 
> >>                 hash-function "-" strength]
> >> 
> >>         where protocol specifies the protocol used for security e.g:
> >>         TLS, SSL3, SSL2, DAA, etc.
> >> 
> >>         Associated with this IPP scheme is an IANA-assigned TCP [TCP]
> >>         port number, 631, which is the default port number used by
> >>         clients to contact IPP servers that are represented by IPP
> >>         URLs.  If another port number is explitly specified, that port
> >>         will be used by the client.
> >> 
> >>         The IPP scheme implies all of the same protocol semantics as
> >>         that of the HTTP [HTTP] scheme, except that, by default, the
> >>         port number used by clients to connect to the server is port
> >>         631. The semantics for clients configured for proxy access is
> >>         different as described below.
> >> 
> >>         The implementation impact of using the new scheme on the
> >>         existing specifications is mainly in the HTTP headers area.
> >>         The IPP scheme URI is explicitly stored in the application/ipp
> >>         MIME object.
> >> 
> >> 
> >>         ------------------------------------------------------
> >>         HTTP Header Usage
> >>         ------------------------------------------------------
> >> 
> >>         When an IPP client obtains an IPP URL, the interpretation
> >>         (translation) of this URL by the client can take one of two
> >>         forms, depending upon whether the client is configured to use
> >>         an HTTP 1.1 proxy server. In both cases, the security
> >>         parameters are passed as part of the HTTP headers to the
> >>         server.  This ensures that the IPP scheme's security parameters
> >>         are received by the server, and the server can reconstruct the
> >>         ipp URI at it's end.
> >> 
> >> 
> >> 
> >>         IPP Client Configured with no proxy server 
> >>         ------------------------------------------------------
> >> 
> >>         When an IPP client (no proxy configured) obtains an "ipp:" URL
> >>         such as
> >>  
> >> "ipp://myhost.com/myprinter/myqueue/AUTH=TLS;RSA-EXPORT40;NULL;MD5",
> >>         it MUST open an TCP connection to port 631 on myhost.com, with
> >>         the following example headers:
> >> 
> >>         POST /myprinter/myqueue HTTP/1.1
> >>         Host: myhost.com:631
> >>         Security-Protocol: TLS; RSA-EXPORT40; NULL; MD5
> >>         Content-type: application/ipp
> >>         Transfer-Encoding: chunked
> >>         ...
> >> 
> >>         In the above example, the client indicates that it wants to
> >>         communicate using the TLS protocol using RSA for encryption and
> >>         40 bit export variety key, no signature and a message digest
> >>         using MD5 one-way hash function.
> >> 
> >>         IPP Client Configured for Proxy Service
> >>         ------------------------------------------------------
> >> 
> >>         When an IPP client that uses a proxy named "myproxy.com"
> >>         obtains the URL
> >>  
> >> "ipp://myhost.com/myprinter/myqueue/AUTH=TLS;RSA-EXPORT40;NULL;MD5",
> >>         it MUST open a TCP connection to myproxy.com with the following
> >>         example headers:
> >> 
> >>         POST http://myhost.com:631/myprinter/myqueue HTTP/1.1
> >>         Host: myproxy.com:8080
> >>         Security-Protocol: TLS; RSA-EXPORT40; NULL; MD5
> >>         Content-type: application/ipp
> >>         Transfer-Encoding: chunked
> >>         ...
> >> 
> >>         Note that the virtual host problem is still being debated in
> >>         the TLS working group, and the above translation for proxy
> >>         service may have to be changed.
> >> 
> >> 
> >>         SERVER GENERATED URIs:
> >>         -----------------------------------------
> >> 
> >>         At the server end several URIs are generated in response to a
> >>         client's request (job query, job cancel, etc.). These URIs will
> >>         use the IPP method with IPP security parameters. The client
> >>         will then use these URIs for their specific needs.  The
> >>         security protocol must match the security protocol used
> >>         initially by the client to communicate with the server. The
> >>         individual security parameters must match the security
> >>         parameters actually used. Note that these parameters may differ
> >>         from the parameters specified in the original IPP URI.
> >> 
> >> 
> >> 
> >> ------
> >> 
> >> 
> >> 
> >> Carl-Uno Manros
> >> Principal Engineer - Advanced Printing Standards - Xerox Corporation
> >> 701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
> >> Phone +1-310-333 8273, Fax +1-310-333 5514
> >> Email: manros at cp10.es.xerox.com
> >
> >
> Carl-Uno Manros
> Principal Engineer - Advanced Printing Standards - Xerox Corporation
> 701 S. Aviation Blvd., El Segundo, CA, M/S: ESAE-231
> Phone +1-310-333 8273, Fax +1-310-333 5514
> Email: manros at cp10.es.xerox.com



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