diff --git a/contrib/sim-rest-server.py b/contrib/sim-rest-server.py
new file mode 100755
index 0000000..0f77dfe
--- /dev/null
+++ b/contrib/sim-rest-server.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+
+# RESTful HTTP service for performing authentication against USIM cards
+#
+# (C) 2021 by Harald Welte <laforge@osmocom.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import json
+import sys
+import argparse
+
+from klein import run, route
+
+from pySim.transport import ApduTracer
+from pySim.transport.pcsc import PcscSimLink
+from pySim.commands import SimCardCommands
+from pySim.cards import UsimCard
+from pySim.exceptions import *
+
+class ApduPrintTracer(ApduTracer):
+    def trace_response(self, cmd, sw, resp):
+        #print("CMD: %s -> RSP: %s %s" % (cmd, sw, resp))
+        pass
+
+@route('/sim-auth-api/v1/slot/<int:slot>')
+def auth(request, slot):
+    """REST API endpoint for performing authentication against a USIM.
+       Expects a JSON body containing RAND and AUTN.
+       Returns a JSON body containing RES, CK, IK and Kc."""
+    try:
+        # there are two hex-string JSON parameters in the body: rand and autn
+        content = json.loads(request.content.read())
+        rand = content['rand']
+        autn = content['autn']
+    except:
+        request.setResponseCode(400)
+        return "Malformed Request"
+
+    try:
+        tp = PcscSimLink(slot, apdu_tracer=ApduPrintTracer())
+        tp.connect()
+    except ReaderError:
+        request.setResponseCode(404)
+        return "Specified SIM Slot doesn't exist"
+    except ProtocolError:
+        request.setResponseCode(500)
+        return "Error"
+    except NoCardError:
+        request.setResponseCode(410)
+        return "No SIM card inserted in slot"
+
+    scc = SimCardCommands(tp)
+    card = UsimCard(scc)
+    # this should be part of UsimCard, but FairewavesSIM breaks with that :/
+    scc.cla_byte = "00"
+    scc.sel_ctrl = "0004"
+    try:
+        card.read_aids()
+        card.select_adf_by_aid(adf='usim')
+        res, sw = scc.authenticate(rand, autn)
+    except SwMatchError as e:
+        request.setResponseCode(500)
+        return "Communication Error %s" % e
+
+    tp.disconnect()
+
+    return json.dumps(res, indent=4)
+
+def main(argv):
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-H", "--host", help="Host/IP to bind HTTP to", default="localhost")
+    parser.add_argument("-p", "--port", help="TCP port to bind HTTP to", default=8000)
+    #parser.add_argument("-v", "--verbose", help="increase output verbosity", action='count', default=0)
+
+    args = parser.parse_args()
+
+    run(args.host, args.port)
+
+if __name__ == "__main__":
+    main(sys.argv)