diff --git a/pyhsslms/hsslms.py b/pyhsslms/hsslms.py
old mode 100644
new mode 100755
index 50b417c..4cbc5d4
--- a/pyhsslms/hsslms.py
+++ b/pyhsslms/hsslms.py
@@ -7,7 +7,7 @@
 # in RFC 8554.
 #
 #
-# Copyright (c) 2020, Vigil Security, LLC
+# Copyright (c) 2020-2021, Vigil Security, LLC
 # All rights reserved.
 #
 # Redistribution and use, with or without modification, are permitted
@@ -78,7 +78,7 @@ def usage(name):
     print("   -w LMOTS_TYPE, --lmots LMOTS_TYPE")
     print("                           Winternitz number")
     print("   -a HASH_ALG, --alg HASH_ALG")
-    print("                           Hash algorithm (only sha256)")
+    print("                           Hash algorithm (sha256 or shake)")
     print(" ")
     print("optional command arguments:")
     print("   -h, --help")
@@ -131,24 +131,56 @@ def main():
                 type=int, choices=[1, 2, 4, 8],
                 metavar='LMOTS_TYPE', help='Winternitz number')
             parser.add_argument('-a', '--alg', dest='alg', default='sha256',
-                type=str, choices=['sha256'],
-                metavar='HASH_ALG', help='Hash algorithm (only sha256)')
+                type=str, choices=['sha256', 'shake'],
+                metavar='HASH_ALG', help='Hash algorithm (sha256 or shake)')
+            parser.add_argument('-t', '--trunc', dest='trunc', default='32',
+                type=str, choices=[32, 24],
+                metavar='TRUNC', help='Hash algorithm truncation size')
             args = parser.parse_args(sys.argv[3:])
 
-            lms_dict = {
-                 5: pyhsslms.lms_sha256_m32_h5,
-                10: pyhsslms.lms_sha256_m32_h10,
-                15: pyhsslms.lms_sha256_m32_h15,
-                20: pyhsslms.lms_sha256_m32_h20,
-                25: pyhsslms.lms_sha256_m32_h25, }
-            lmots_dict = {
-                 1: pyhsslms.lmots_sha256_n32_w1,
-                 2: pyhsslms.lmots_sha256_n32_w2,
-                 4: pyhsslms.lmots_sha256_n32_w4,
-                 8: pyhsslms.lmots_sha256_n32_w8, }
             levels = args.levels
-            lms_type = lms_dict[args.lms]
-            lmots_type = lmots_dict[args.lmots]
+            if args.alg == 'sha256':
+                if args.trunc == 32:
+                     if args.lms ==  5: lms_type = pyhsslms.lms_sha256_m32_h5
+                     if args.lms == 10: lms_type = pyhsslms.lms_sha256_m32_h10
+                     if args.lms == 15: lms_type = pyhsslms.lms_sha256_m32_h15
+                     if args.lms == 20: lms_type = pyhsslms.lms_sha256_m32_h20
+                     if args.lms == 25: lms_type = pyhsslms.lms_sha256_m32_h25
+                     if args.lmots == 1: lmots_type = pyhsslms.lmots_sha256_n32_w1
+                     if args.lmots == 2: lmots_type = pyhsslms.lmots_sha256_n32_w2
+                     if args.lmots == 4: lmots_type = pyhsslms.lmots_sha256_n32_w4
+                     if args.lmots == 8: lmots_type = pyhsslms.lmots_sha256_n32_w8
+                else: # args.trunc == 24
+                     if args.lms ==  5: lms_type = pyhsslms.lms_sha256_m24_h5
+                     if args.lms == 10: lms_type = pyhsslms.lms_sha256_m24_h10
+                     if args.lms == 15: lms_type = pyhsslms.lms_sha256_m24_h15
+                     if args.lms == 20: lms_type = pyhsslms.lms_sha256_m24_h20
+                     if args.lms == 25: lms_type = pyhsslms.lms_sha256_m24_h25
+                     if args.lmots == 1: lmots_type = pyhsslms.lmots_sha256_n24_w1
+                     if args.lmots == 2: lmots_type = pyhsslms.lmots_sha256_n24_w2
+                     if args.lmots == 4: lmots_type = pyhsslms.lmots_sha256_n24_w4
+                     if args.lmots == 8: lmots_type = pyhsslms.lmots_sha256_n24_w8
+            else: # args.alg == 'shake'
+                if args.trunc == 32:
+                     if args.lms ==  5: lms_type = pyhsslms.lms_shake_m32_h5
+                     if args.lms == 10: lms_type = pyhsslms.lms_shake_m32_h10
+                     if args.lms == 15: lms_type = pyhsslms.lms_shake_m32_h15
+                     if args.lms == 20: lms_type = pyhsslms.lms_shake_m32_h20
+                     if args.lms == 25: lms_type = pyhsslms.lms_shake_m32_h25
+                     if args.lmots == 1: lmots_type = pyhsslms.lmots_shake_n32_w1
+                     if args.lmots == 2: lmots_type = pyhsslms.lmots_shake_n32_w2
+                     if args.lmots == 4: lmots_type = pyhsslms.lmots_shake_n32_w4
+                     if args.lmots == 8: lmots_type = pyhsslms.lmots_shake_n32_w8
+                else: # args.trunc == 24
+                     if args.lms ==  5: lms_type = pyhsslms.lms_shake_m24_h5
+                     if args.lms == 10: lms_type = pyhsslms.lms_shake_m24_h10
+                     if args.lms == 15: lms_type = pyhsslms.lms_shake_m24_h15
+                     if args.lms == 20: lms_type = pyhsslms.lms_shake_m24_h20
+                     if args.lms == 25: lms_type = pyhsslms.lms_shake_m24_h25
+                     if args.lmots == 1: lmots_type = pyhsslms.lmots_shake_n24_w1
+                     if args.lmots == 2: lmots_type = pyhsslms.lmots_shake_n24_w2
+                     if args.lmots == 4: lmots_type = pyhsslms.lmots_shake_n24_w4
+                     if args.lmots == 8: lmots_type = pyhsslms.lmots_shake_n24_w8
     
         pyhsslms.HssLmsPrivateKey.genkey(keyname, levels=levels,
             lms_type=lms_type, lmots_type=lmots_type)