diff --git a/Makefile b/Makefile
index dedd011..e0a5ec9 100644
--- a/Makefile
+++ b/Makefile
@@ -3,17 +3,22 @@
 # File-version: 5
 
 INPUTS = $(wildcard *.sol)
-OUTPUTS = $(patsubst %.sol, %.json, $(INPUTS))
+OUTPUTS_JSON = $(patsubst %.sol, %.json, $(INPUTS))
+OUTPUTS_INTERFACE = $(patsubst %.sol, %.interface, $(INPUTS))
+OUTPUTS = ${OUTPUTS_JSON} ${OUTPUTS_INTERFACE}
 PREFIX = /usr/local/share/cic/solidity/abi
 
 #%.abi.json: $(wildcard *.sol)
 #	install -vDm0644 $@ $(PREFIX)/$@
 
-.SUFFIXES: .sol .json
+.SUFFIXES: .sol .json .interface
 
 .sol.json:
 	solc $(basename $@).sol --abi | awk 'NR>3' > $@
 
+.sol.interface:
+	bash $(basename $@).sol > $@
+
 all: $(OUTPUTS)
 
 install: $(OUTPUTS)
diff --git a/calculate_eip165.py b/calculate_eip165.py
new file mode 100644
index 0000000..97e8d52
--- /dev/null
+++ b/calculate_eip165.py
@@ -0,0 +1,29 @@
+# standard imports
+import logging
+import sys
+
+# external imports
+import sha3
+
+#logging.basicConfig(level=logging.WARNING)
+logging.basicConfig(level=logging.DEBUG)
+logg = logging.getLogger()
+
+if __name__ == '__main__':
+    f = open(sys.argv[1], 'r')
+    z = b''
+    for i in range(32):
+        z += b'\x00'
+    while True:
+        l = f.readline().rstrip()
+        if l == '':
+            break
+        logg.debug('line {}'.format(l))
+        h = sha3.keccak_256()
+        h.update(l.encode('utf-8'))
+        r = h.digest()
+        z = bytes([a ^ b for a, b in zip(r, z)])
+        logg.debug('{} -> {}'.format(r.hex(), z.hex()))
+    f.close()
+
+    print(z[:4].hex())
diff --git a/calculate_erc165.py b/calculate_erc165.py
deleted file mode 100644
index dcf1cfa..0000000
--- a/calculate_erc165.py
+++ /dev/null
@@ -1,16 +0,0 @@
-import sys
-import web3
-
-f = open(sys.argv[1], 'r')
-z = b''
-for i in range(32):
-    z += b'\x00'
-while True:
-    l = f.readline()
-    if l == '':
-        break
-    print('line {}'.format(l))
-    h = web3.Web3.keccak(text=l)
-    z = bytes([a ^ b for a, b in zip(h, z)])
-    print(h.hex(), z.hex())
-f.close()
diff --git a/parse.py b/reduce_to_methods.py
similarity index 100%
rename from parse.py
rename to reduce_to_methods.py
diff --git a/to_interface.sh b/to_interface.sh
new file mode 100644
index 0000000..825e468
--- /dev/null
+++ b/to_interface.sh
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+d=`mktemp -d`
+b=`basename $1`
+s=${b%%.*}
+echo $s
+python3 reduce_to_methods.py $1 > $d/$b
+python3 calculate_eip165.py $d/$b > ${s}.interface
+>&2 echo $d/$b