diff --git a/extras/test/runtests b/extras/test/runtests
index e3af55a..c25ec23 100755
--- a/extras/test/runtests
+++ b/extras/test/runtests
@@ -200,7 +200,7 @@ test-tomb-shared() {
     res=0
     tt dig -s 20 /tmp/shared.tomb
     { test $? = 0 } || { res=1 }
-    tt forge /tmp/shared.tomb.key -r $gpgid_1,$gpgid_2 \
+    tt forge /tmp/shared.tomb.key -r $gpgid_1,$gpgid_2 --shared \
         --ignore-swap --unsafe --use-urandom 
     { test $? = 0 } || { res=1 }
     tt lock /tmp/shared.tomb -k /tmp/shared.tomb.key \
@@ -214,17 +214,17 @@ test-tomb-shared() {
     
     notice "Testing changing recipients on a shared Tomb"
     tt passwd -k /tmp/shared.tomb.key -r $gpgid_1,$gpgid_2 \
-        -R $gpgid_2,$gpgid_1
+        -R $gpgid_2,$gpgid_1 --shared
     { test $? = 0 } && { results+=(shared-passwd SUCCESS) }
     
     notice "Testing setkey on a shared Tomb"
     rm -f /tmp/new.shared.tomb.key
     res=0
-    tt forge /tmp/new.shared.tomb.key -r $gpgid_1,$gpgid_2 \
+    tt forge /tmp/new.shared.tomb.key -r $gpgid_1,$gpgid_2 --shared\
         --ignore-swap --unsafe --use-urandom
     { test $? = 0 } || { res=1 }
     tt setkey -k /tmp/new.shared.tomb.key /tmp/shared.tomb.key /tmp/shared.tomb \
-        -r $gpgid_2,$gpgid_1
+        -r $gpgid_2,$gpgid_1 --shared
     { test $? = 0 } || { res=1 }
     { test $res = 0 } && { results+=(shared-setkey SUCCESS) }
 }
diff --git a/tomb b/tomb
index d7ad4b5..15ff175 100755
--- a/tomb
+++ b/tomb
@@ -864,6 +864,14 @@ _recipients_arg() {
     return 0
 }
 
+# $1 is a GPG key recipient
+# Print the fingerprint of the GPG key
+_fingerprint() {
+    local recipient="$1"
+    gpg --with-colons --fingerprint "$recipient" | grep fpr | head -1 | cut -d ':' -f 10 | sed 's/.\{4\}/& /g'
+}
+
+
 # $1 is the encrypted key contents we are checking
 is_valid_key() {
     local key="$1"       # Unique argument is an encrypted key to test
@@ -1210,6 +1218,19 @@ gen_key() {
             recipients=(${(s:,:)$(option_value -r)})
         }
         
+        [ "${#recipients}" -gt 1 ] && {
+            if option_is_set --shared; then
+                _warning "You are going to encrypt a tomb key with ${#recipients} recipients."
+                _warning "It is your responsibility to check the fingerprint of these recipients."
+                _warning "The fingerprints are:"
+                for gpg_id in ${recipients[@]}; do
+                    _warning "    `_fingerprint "$gpg_id"`"
+                done
+            else
+                _failure "You need to use the option '--shared' to enable sharing support"
+            fi
+        }
+        
         { is_valid_recipients $recipients } || {
             _failure "You set an invalid GPG ID."
         }
@@ -2698,13 +2719,13 @@ main() {
     subcommands_opts[create]="" # deprecated, will issue warning
 
     # -o in forge and lock is used to pass an alternate cipher.
-    subcommands_opts[forge]="-ignore-swap k: -kdf: o: -tomb-pwd: -use-urandom r: "
+    subcommands_opts[forge]="-ignore-swap k: -kdf: o: -tomb-pwd: -use-urandom r: -shared "
     subcommands_opts[dig]="-ignore-swap s: -size=s "
     subcommands_opts[lock]="-ignore-swap k: -kdf: o: -tomb-pwd: r: "
-    subcommands_opts[setkey]="k: -ignore-swap -kdf: -tomb-old-pwd: -tomb-pwd: r: "
+    subcommands_opts[setkey]="k: -ignore-swap -kdf: -tomb-old-pwd: -tomb-pwd: r: -shared "
     subcommands_opts[engrave]="k: "
 
-    subcommands_opts[passwd]="k: -ignore-swap -kdf: -tomb-old-pwd: -tomb-pwd: r: R: "
+    subcommands_opts[passwd]="k: -ignore-swap -kdf: -tomb-old-pwd: -tomb-pwd: r: R: -shared "
     subcommands_opts[close]=""
     subcommands_opts[help]=""
     subcommands_opts[slam]=""