sig binary format

[David Shaw]

On Apr 5, 2011, at 12:03 PM, Jean-Jacques Brucker wrote:

> 
> Hi, I have a question concerning the first octet of *.sig file (created with --detach-sign option). 
> 
> I have see almost data match section 5.2.3. of the RFC4880, but i am asking me why is the first octet of a *.sig file (packet tag) 0x88 ?
> According to section 4.3 of RFC4880 0x88 means "Compressed Data Packet", I was instead expecting 0x82 for "Signature Packet" !?

0x88 means old-style signature packet.  0x88 == 10001000.  Bit 6 is not set, so its an old-style tag. The relevant bits to indicate a packet type in an old-style tag are bits 5 through 2, so 0010.  0010 == 2, and 2 is a signature packet.

David