+much less secure.
+<footnote>Version 4 keys are keys conforming to
+the OpenPGP standard as defined in RFC 2440. Version 4 is the key
+type that has always been created when using GnuPG. PGP versions
+since 5.x also could create v4 keys, the other choice having beein
+pgp 2.6.x compatible v3 keys (also called "legacy RSA" by PGP).
+<p>
+Version 4 (primary) keys can either use the RSA or the DSA algorithms,
+so this has nothing to do with GnuPG's question about "which kind
+of key do you want: (1) DSA and Elgamal, (2) DSA (sign only), (5)
+RSA (sign only). If you don't have any special requirements just pick
+the defailt.
+<p>
+The easiest way to tell whether an existing key is a v4 key or a v3
+(or v2) key is to look at the fingerprint:
+Fingerprints of version 4 keys are the SHA-1 hash of some key matieral,
+so they are 40 hex digits, usually grouped in blocks of 4. Fingerprints
+of older key format versions used MD5 and are generally shown in blocks
+of 2 hex digits. For example if your fingerprint looks like
+<tt>5B00 C96D 5D54 AEE1 206B AF84 DE7A AF6E 94C0 9C7F</tt>
+then it's a v4 key.
+<p>
+Another possibility is to pipe the key into <prgn>pgpdump</prgn>,
+which will say something like "Public Key Packet - Ver 4".
+<p>
+Also note that your key must be self-signed (i.e. it has to sign
+all its own user IDs; this prevents user ID tampering). All
+modern OpenPGP software does that automatically, but if you
+have an older key you may have to manually add those signatures.
+</footnote>