Hi Zemer, > Since no class is specified, both tags default to > context-specific
This specification is not a context-specific tag class but its a APPLICATION tag type which is given ([APPLICATION 20]) in the specification itself. Please correct me if im wrong. --- Zemer Margolin <[EMAIL PROTECTED]> wrote: > Hi, > For that reason exactly, the tagged typed were > added. > In this case the tag [2] is assigned to usec and [3] > to seq-number. > Since no class is specified, both tags default to > context-specific, the ambiguity you've mentioned is > removed and you can determine which elements are > present. > Hope I could be of help > Zemer Margolin > Tel: +9723-765-7571 > E-mail: [EMAIL PROTECTED] > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Gustavo V. > G. C. Rios > Sent: Wednesday, October 29, 2003 3:28 AM > To: [EMAIL PROTECTED] > Subject: [ASN.1] (I AM DESPERATE, PLEASE) Beginner > Question: ASN1 & Kerberos (rfc1510.txt) > > Dear gentleman, > > i am beginning studying ASN as an requirement for > understanding kerberV > security protocol. One of its message specification > is the following: > > KRB-SAFE-BODY ::= [APPLICATION 20] SEQUENCE { > user-data[0] OCTET STRING, > timestamp[1] KerberosTime OPTIONAL, > usec[2] INTEGER OPTIONAL, > seq-number[3] INTEGER OPTIONAL, > s-address[4] HostAddress, > r-address[5] HostAddress OPTIONAL > } > > My doubt regards with the decoding of the input > stream. For the usec and > seq-number values i have three possible scenarios: > > 0) The two values are present, > 1) None of them are present, > 2) Just one of them is present. > > Since both are optional and have the same type, for > scenario 2, how will > i *correctly* decode an input stream? I.e. , the > next value to be decode > is an integer, but will i see it as the usec or the > seq-number value? > __________________________________ Do you Yahoo!? The New Yahoo! Shopping - with improved product search http://shopping.yahoo.com
