--- draft-ietf-openpgp-formats-00.txt.orig	Thu Dec  4 10:55:35 1997
+++ draft-ietf-openpgp-formats-00.txt	Thu Dec  4 11:06:14 1997
@@ -2145,11 +2145,15 @@
 
 8.2 V4 Key IDs and Fingerprints
 
-A V4 fingerprint is the 160-bit SHA-1 hash of the one-octet Packet Tag,
-followed by the two-octet packet length, followed by the entire Public
-Key packet starting with the version field.  The key ID is either the
-low order 32 bits or 64 bits of the fingerprint.  Here are the fields
-of the hash material, with the example of a DSA key:
+A V4 fingerprint is the 160-bit SHA-1 hash of a valid old-style public
+key packet containing the public key in question.  This packet consists
+of the public key packet tag, followed by a two-octet packet length
+field, followed by the entire Public Key material starting with the
+version field.  Note that the packet used for fingerprint generation will
+always be denoted as a Public Key Packet (content tag 6), but never as a
+Subkey Packet (content tag 14). The key ID is either the low order 32
+bits or 64 bits of the fingerprint. Here are the fields of the hash
+material, with the example of a DSA key:
 
     a.1) 0x99 (1 byte)
     a.2) high order length byte of (b)-(f) (1 byte)