There are a few border cases that should be verified
when parsing signature headers:
- no space after ";" before next tag name
- spaces before the tag name
- spaces between tag name and "="
- spaces between "=" and tag value
- spaces between tag value an ";"
- spaces between header names and ":" in "h="
The same tests should also be verified in key record
and policy record processing.
It has been reported that at least the last one is not