Java 1.5 ASN encoding error

[Dangi, Salil]

Java 1.5 is not encoding integers properly.
 
I am using java 1.5 to generate a service ticket token (AP Request) for
a service running on Unisys machines.
This token can not be parsed properly due to ASN encoding errors.
 
There is an Authenticator in this AP request.
Within the authenticator, there is an optional field for seq-number of
type integer.
The seq-number is a unsigned integer that can go from 0 to 2**32 -1 with
a random initial value.
 
During my sample runs, I saw that Java 1.5 implementation is either
sending an integer encoded in 2 bytes or an integer encoded in 4 bytes.
When this is encoded in 2 bytes, there is no issue. When this is encoded
in 4 bytes, the encoding is not correct. The value looks something like
FFFFXXXX (A706 0204 FFFFXXXX).
 
As per ASN encoding, this should be encoded as 00FFFFXXXX (A707 0205
00FFFFXXXX) since ASN encoding does not allow top 9 bit to be either all
ones or all zeroes.
 
Has anyone seen this problem?
 
sample Hex dump of the seq-number field from the Authenticator
 
A70402020398        Works
A704020207CB        Works
A7060204FFFFF77F    Fails
A7060204FFFFFA59    Fails
A7060204FFFFF96D    Fails
A7060204FFFFF3F8    Fails