diff --git a/Lib/fontTools/misc/eexec.py b/Lib/fontTools/misc/eexec.py
index 41293fcc6..844ce55a4 100644
--- a/Lib/fontTools/misc/eexec.py
+++ b/Lib/fontTools/misc/eexec.py
@@ -44,10 +44,13 @@ def encrypt(plainstring, R):
 
 
 def hexString(s):
-	xxx
+	import binascii
+	return binascii.hexlify(s)
 
 def deHexString(h):
-	xxx
+	import binascii
+	h = "".join(h.split())
+	return binascii.unhexlify(h)
 
 
 def _test():