Quick FLEXlm questions

[Kerlingen]

I'm totally new to FLEXlm, so I have a few short questions. I have a (trial) license file which contains many entries like this:

PACKAGE feat1 XYZ 2011.0813 11AA22BB33CC COMPONENTS=Comp1 \
ck=107 SIGN=44DD55EE66FF

INCREMENT feat1 XYZ 2011.0813 13-aug-2011 uncounted \
1A2B3C4D5E6F VENDOR_STRING="EVAL=EVAL VERSION" \
HOSTID=ID=03407177 ck=147 SN=12345678 \
SIGN=EFCDAB896745

PACKAGE feat2 XYZ 2011.0813 [...]

1. Is it possible to change to expiration date and apply a valid signature again without knowing some data available only to the software vendor?
2. What signature algorithm is used? What strength does it have?
3. Are "11AA22BB33CC" and "44DD55EE66FF" part of the same signature or two different signatures? What do they sign if they are different ones?
4. Is "ck=107" a part of FLEXlm or something which the software vendor inserted?
5. What does "HOSTID=ID=03407177" mean? I read that "HOSTID=ANY" is the thing which I want, but even the trial license is not locked to my computer or something.
6. What is the difference between the PACKAGE and the INCREMENT part? Couldn't someone just put the INCREMENT entries in the PACKAGE part and would only need one signature instead of two?