+# generate a subkey with the 'a' usage flags set
+# FIXME: this needs some tweaking to clean it up
+gen_subkey(){
+ local keyID
+ local gpgOut
+ local userID
+
+ keyID="$1"
+
+ gpgOut=$(gpg --fixed-list-mode --list-keys --with-colons \
+ "$keyID" 2> /dev/null)
+
+ # return 1 if there only "tru" lines are output from gpg
+ if [ -z "$(echo "$gpgOut" | grep -v '^tru:')" ] ; then
+ failure "Key ID '$keyID' not found."
+ fi
+
+ # set subkey defaults
+ SUBKEY_TYPE=${SUBKEY_TYPE:-"RSA"}
+ #SUBKEY_LENGTH=${SUBKEY_LENGTH:-"2048"}
+ SUBKEY_USAGE=${SUBKEY_USAGE:-"auth"}
+ SUBKEY_EXPIRE=${SUBKEY_EXPIRE:-"0"}
+ cat <<EOF
+Please specify how long the key should be valid.
+ 0 = key does not expire
+ <n> = key expires in n days
+ <n>w = key expires in n weeks
+ <n>m = key expires in n months
+ <n>y = key expires in n years
+EOF
+ read -p "Key is valid for? ($SUBKEY_EXPIRE) " SUBKEY_EXPIRE; SUBKEY_EXPIRE=${SUBKEY_EXPIRE:-"0"}
+
+ # generate the list of commands that will be passed to edit-key
+ editCommands=$(cat <<EOF
+addkey
+7
+S
+E
+A
+Q
+$SUBKEY_LENGTH
+$SUBKEY_EXPIRE
+save
+EOF
+)
+
+ echo "generating subkey..."
+ echo "$editCommands" | gpg --expert --command-fd 0 --edit-key "$keyID"
+}
+