diff --git a/jmdaemon/jmdaemon/message_channel.py b/jmdaemon/jmdaemon/message_channel.py
index 277abc09d..96be37ec6 100644
--- a/jmdaemon/jmdaemon/message_channel.py
+++ b/jmdaemon/jmdaemon/message_channel.py
@@ -8,6 +8,7 @@
     encrypted_commands, commitment_broadcast_list, offername_list,\
     fidelity_bond_cmd_list
 from jmbase.support import get_log
+from jmbase import hextobin
 from functools import wraps
 
 log = get_log()
@@ -918,7 +919,6 @@ def on_privmsg(self, nick, message):
         #Other ill formatted messages will be caught in the try block.
         if len(message) < 2:
             return
-
         if message[0] != COMMAND_PREFIX:
             log.debug('message not a cmd')
             return
@@ -926,16 +926,31 @@ def on_privmsg(self, nick, message):
         if cmd_string not in plaintext_commands + encrypted_commands:
             log.debug('cmd not in cmd_list, line="' + message + '"')
             return
+        badsigmsg = "Sig not properly appended to privmsg, ignoring"
         #Verify nick ownership
-        sig = message[1:].split(' ')[-2:]
+        try:
+            pub, sig = message[1:].split(' ')[-2:]
+        except Exception:
+            log.debug(badsigmsg)
+            return
         #reconstruct original message without cmd
         rawmessage = ' '.join(message[1:].split(' ')[1:-2])
-        #sanity check that the sig was appended properly
-        if len(sig) != 2 or len(rawmessage) == 0:
-            log.debug("Sig not properly appended to privmsg, ignoring")
+        # can happen if not enough fields for command, (stuff), pub, sig:
+        if len(rawmessage) == 0:
+            log.debug(badsigmsg)
+            return
+        # Sanitising signature before attempting to verify:
+        # Note that the sig itself can be any garbage, because `ecdsa_verify`
+        # swallows any fail and returns False; but the pubkey is assumed
+        # to be hex-encoded, and the signature base64 encoded, so check early:
+        try:
+            dummypub = hextobin(pub)
+            dummysig = base64.b64decode(sig)
+        except Exception:
+            log.debug(badsigmsg)
             return
         self.daemon.request_signature_verify(
-            rawmessage + str(self.hostid), message, sig[1], sig[0], nick,
+            rawmessage + str(self.hostid), message, sig, pub, nick,
             NICK_HASH_LENGTH, NICK_MAX_ENCODED, str(self.hostid))
 
     def on_verified_privmsg(self, nick, message):
diff --git a/jmdaemon/test/test_message_channel.py b/jmdaemon/test/test_message_channel.py
index a9a8bfbb6..d68321bcf 100644
--- a/jmdaemon/test/test_message_channel.py
+++ b/jmdaemon/test/test_message_channel.py
@@ -17,8 +17,11 @@
 import threading
 import binascii
 import jmbitcoin as bitcoin
+from jmbase import bintohex
 from dummy_mc import DummyMessageChannel
 
+# note: completely invalid sig is fine, as long as it's encoded right:
+dummy_sig_str = bintohex(b"\x02"*33) + " " + base64.b64encode(b"\x01"*72).decode()
 
 jlog = get_log()
 
@@ -151,8 +154,8 @@ def test_setup_mc():
     #Simulate order receipt on 2 of 3 msgchans from this nick;
     #note that it will have its active chan set to mc "1" because that
     #is the last it was seen on:
-    dmcs[0].on_privmsg(cp1, "!reloffer 0 4000 5000 100 0.2 abc def")
-    dmcs[1].on_privmsg(cp1, "!reloffer 0 4000 5000 100 0.2 abc def")
+    dmcs[0].on_privmsg(cp1, "!reloffer 0 4000 5000 100 0.2 " + dummy_sig_str)
+    dmcs[1].on_privmsg(cp1, "!reloffer 0 4000 5000 100 0.2 " + dummy_sig_str)
     time.sleep(0.5)
     #send back a response
     mcc.privmsg(cp1, "fill", "0")
@@ -210,7 +213,7 @@ def test_setup_mc():
     #first, pretend they all showed up on all 3 mcs:
     for m in dmcs:
         for cp in cps:
-            m.on_privmsg(cp, "!reloffer 0 400000 500000 100 0.002 abc def")
+            m.on_privmsg(cp, "!reloffer 0 400000 500000 100 0.002 " + dummy_sig_str)
     #next, call main fill function
     mcc.fill_orders(new_offers, 1000, "dummypubkey", "dummycommit")
     #now send a dummy transaction to this same set.
@@ -242,7 +245,7 @@ def test_setup_mc():
     #have the cps rearrive
     for m in dmcs:
         for cp in cps:
-            m.on_privmsg(cp, "!reloffer 0 4000 5000 100 0.2 abc def")
+            m.on_privmsg(cp, "!reloffer 0 4000 5000 100 0.2 " + dummy_sig_str)
 
     #####################################################################
     #next series of messages are to test various normal and abnormal
@@ -255,7 +258,7 @@ def test_setup_mc():
     #invalid missing field
     dmcs[0].on_pubmsg(cps[2], "!hp2")
     #receive commitment via privmsg to trigger commitment_transferred
-    dmcs[0].on_privmsg(cps[2], "!hp2 deadbeef abc def")
+    dmcs[0].on_privmsg(cps[2], "!hp2 deadbeef " + dummy_sig_str)
     #simulate receipt of order cancellation
     #valid
     dmcs[0].on_pubmsg(cps[2], "!cancel 2")