How to add authentication capabilities to an existing key?

Tue Sep 10 10:31:04 CEST 2013

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Is there a good way to add authentication capabilities to an existing
RSA key? I see how to toggle it if I create a new subkey but not how
to add it to an existing key.

Thanks,
Anthony

- -- 
Anthony Papillion
XMPP/Jabber:      cypherpunk at patts.us
OTR Fingerprint:  4F5CE6C07F5DCE4A2569B72606E5C00A21DA24FA
SIP:              17772471988 at callcentric.com
PGP Key:          0x53B04B15

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