diff --git a/pow.py b/pow.py
old mode 100644
new mode 100755
index 4285fe0..1786a87
--- a/pow.py
+++ b/pow.py
@@ -1,5 +1,8 @@
+#!/usr/bin/env python3
+
 import hashlib
 import os
+import argparse
 
 
 epoch1_threshold = 0xffffffc000000000
@@ -10,12 +13,13 @@
 # return a random 8-byte nonce as an integer
 def random_nonce() -> int:
     nonce_bytes = os.urandom(8)
-    return int.from_bytes(nonce_bytes, "little")
+    return int.from_bytes(nonce_bytes, 'little')
 
 
+# Return the calculated difficulty for a root and nonce
 # take a nonce (8 byte unsigned int) and a root (32 byte unsigned int) and produce
 # blake2b(nonce + root), which is a hash of the nonce and the root
-# the output hash is an 8 byte unsigned integer
+# the output hash is an 8 byte unsigned integer (calculated difficulty)
 def generate_pow_hash(nonce: int, root: int) -> int:
     alg = hashlib.blake2b(digest_size=8)
     alg.update(nonce.to_bytes(8, byteorder='little'))
@@ -23,6 +27,7 @@ def generate_pow_hash(nonce: int, root: int) -> int:
     return int.from_bytes(alg.digest(), byteorder='little')
 
 
+# returns a nonce that satisfies the difficulty contraint
 def generate_pow_for_root_and_difficulty(root: int, target_difficulty: int) -> int:
     nonce = random_nonce()
     difficulty = generate_pow_hash(nonce, root)
@@ -30,3 +35,60 @@ def generate_pow_for_root_and_difficulty(root: int, target_difficulty: int) -> i
         nonce = random_nonce()
         difficulty = generate_pow_hash(nonce, root)
     return nonce
+
+
+def verify_pow_for_root_and_difficulty(root: int, target_difficulty: int, work : int) -> int:
+    digest = generate_pow_hash(work, root)
+    return digest >= target_difficulty
+
+
+def calculate_multiplier(base_diff: int, diff) -> int:
+    return (2**64 - args.difficulty) / (2**64 - calculated_diff)
+
+
+def parse_int(val):
+    return int(val, 16) if val.startswith('0x') else int(val)
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(description='Accept arguments for verify or generate mode.')
+    subparsers = parser.add_subparsers(dest='mode', help='Mode selection')
+
+    verify_parser = subparsers.add_parser('verify', help='Verify mode')
+    verify_parser.add_argument('root', type=parse_int, help='Root value (decimal or hexadecimal)')
+    verify_parser.add_argument('difficulty', type=parse_int, help='Target difficulty value (decimal or hexadecimal)')
+    verify_parser.add_argument('work', type=parse_int, help='Work value (decimal or hexadecimal)')
+
+    generate_parser = subparsers.add_parser('generate', help='Generate mode')
+    generate_parser.add_argument('root', type=parse_int, help='Root value (decimal or hexadecimal)')
+    generate_parser.add_argument('difficulty', type=parse_int, help='Target difficulty value (decimal or hexadecimal)')
+
+    args = parser.parse_args()
+    return args
+
+
+if __name__ == '__main__':
+    args = parse_args()
+
+    if args.mode == 'verify':
+        print('Work:', args.work)
+        print('Root:', args.root)
+        print('Difficulty:', args.difficulty)
+
+        calculated_diff = generate_pow_hash(args.work, args.root)
+        print(f'Calculated difficulty : 0x{calculated_diff:08X}')
+        print(f'Target difficulty     : 0x{args.difficulty:08X}')
+        mult = calculate_multiplier(args.difficulty, calculated_diff)
+        print(f'Multiplier            : {mult}')
+        print('Verify: %s' % (calculated_diff >= args.difficulty))
+
+    if args.mode == 'generate':
+        print(f'Root: {args.root:032X}')
+        print(f'Target Difficulty  : 0x{args.difficulty:08X}')
+        nonce = generate_pow_for_root_and_difficulty(args.root, args.difficulty)
+        calculated_diff = generate_pow_hash(nonce, args.root)
+        print(f'       Difficulty  : 0x{calculated_diff:08X}')
+        print(f'Generated POW nonce: 0x{nonce:08X}')
+        mult = calculate_multiplier(args.difficulty, calculated_diff)
+        print(f'Multiplier         : {mult}')
+        assert verify_pow_for_root_and_difficulty(args.root, args.difficulty, nonce)