oeap works

src-py/plexcryptool/scripts/oaep_rsa.py

@@ -7,12 +7,46 @@ Perform RSA-OAEP
 @source: https://git.cscherr.de/PlexSheep/plexcryptool/src/branch/master/plexcryptool/trash-hash.py
 """
 
+import argparse
 import hashlib
 import random
 from math import floor
 
 # the given key in the assignment
 GIVEN_PUB_KEY = (0xAF5466C26A6B662AC98C06023501C9DF6036B065BD1F6804B1FC86307718DA4048211FD68A06917DE6F81DC018DCAF84B38AB77A6538BA2FE6664D3FB81E4A0886BBCDAB071AD6823FE20DF1CD67D33FB6CC5DA519F69B11F3D48534074A83F03A5A9545427720A30A27432E94970155A026572E358072023061AF65A2A18E85, 0x10001)
+GIVEN_MASK_FOR_DB = bytearray.fromhex("""
+ea600669f6f16b3a2ad05d4b6d9b23911c8cc432fddd8d34a68d88af
+3d787b7eebf6cd1b720812086758ce56e24ab819ccd8fb5eedb1cae9
+f6f895667d7f89d0454b828777ecabc040a649c8956e78ec1c721370
+663065cbc343deabad9eb6f2aceab6bfed5beb232cc55413bfffa06e
+68627d7ec3ded5
+""")
+GIVEN_DB = bytearray.fromhex("""
+00000000000000000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000000000000000
+00000000000000000000000000000000000000000000000000000000
+00000000000000000000000000000000000001466f6f626172203132
+33343536373839
+""")
+GIVEN_MASKED_DB = bytearray.fromhex("""
+ea600669f6f16b3a2ad05d4b6d9b23911c8cc432fddd8d34a68d88af
+3d787b7eebf6cd1b720812086758ce56e24ab819ccd8fb5eedb1cae9
+f6f895667d7f89d0454b828777ecabc040a649c8956e78ec1c721370
+663065cbc343deabad9eb6f2aceab6bfed5bea6543aa3672cddf915c
+5b564848f4e6ec
+""")
+GIVEN_MASK_FOR_SEED = bytearray.fromhex("713162084a4e0e6d ")
+GIVEN_MASKED_SEED = bytearray.fromhex("db2040f6425bb082")
+GIVEN_SEED = 0xaa1122fe0815beef
+GIVEN_SEED_BYTES = bytearray.fromhex("aa1122fe0815beef")
+GIVEN_MSG = bytearray.fromhex("466f6f62617220313233343536373839")
+GIVEN_OAEP = bytearray.fromhex("""
+00db2040f6425bb082ea600669f6f16b3a2ad05d4b6d9b23911c8cc4
+32fddd8d34a68d88af3d787b7eebf6cd1b720812086758ce56e24ab8
+19ccd8fb5eedb1cae9f6f895667d7f89d0454b828777ecabc040a649
+c8956e78ec1c721370663065cbc343deabad9eb6f2aceab6bfed5bea
+6543aa3672cddf915c5b564848f4e6ec
+""")
 
 SEED_LENGTH = 8 # bytes
 
@@ -60,80 +94,102 @@ def calclen(n: int) -> int:
     else: 
         return floor(len)
 
-def rsa_oaep_inner(seed: bytearray, block: bytearray) -> tuple[bytearray, bytearray]:
+def rsa_oaep_inner(seed: bytearray, block: bytearray, verbose: bool) -> tuple[bytearray, bytearray]:
     """
     inner function of rsa-oaep
     """
+    assert type(seed) == bytearray
     mgf_seed = mgf1(seed, len(block))
-    print("mgf1(seed):\n%s" % mgf_seed.hex())
     masked_db = byte_xor(mgf_seed, block)
-    print("mgf1(seed) ^ block:\n%s" % masked_db.hex())
     mask_seed = mgf1(masked_db, len(seed))
-    print("mgf1(mgf1(seed) ^ block):\n%s" % mask_seed.hex())
     masked_seed = byte_xor(seed, mask_seed)
+    if verbose:
+        print("mgf1(seed):\n%s" % mgf_seed.hex())
+        print("mgf1(seed) ^ block:\n%s" % masked_db.hex())
+        print("mgf1(mgf1(seed) ^ block):\n%s" % mask_seed.hex())
         print("mgf1(mgf1(seed) ^ block) ^ seed:\n%s" % masked_seed.hex())
     return (masked_seed, masked_db)
 
 def test_rsa_oaep_inner():
-    seed: bytearray = bytearray.fromhex("aa1122fe0815beef")
+    result = rsa_oaep_inner(GIVEN_SEED_BYTES, GIVEN_DB, True)
-    db: bytearray = bytearray.fromhex("""
-    00000000000000000000000000000000000000000000000000000000
-    00000000000000000000000000000000000000000000000000000000
-    00000000000000000000000000000000000000000000000000000000
-    00000000000000000000000000000000000001466f6f626172203132
-    33343536373839
-    """)
-    print("seed:\n%s" % seed.hex())
-    print("db:\n%s" % db.hex())
 
-    result = rsa_oaep_inner(seed, db)
-
-    GIVEN_MASK_FOR_DB = bytearray.fromhex("""
-    ea600669f6f16b3a2ad05d4b6d9b23911c8cc432fddd8d34a68d88af
-    3d787b7eebf6cd1b720812086758ce56e24ab819ccd8fb5eedb1cae9
-    f6f895667d7f89d0454b828777ecabc040a649c8956e78ec1c721370
-    663065cbc343deabad9eb6f2aceab6bfed5beb232cc55413bfffa06e
-    68627d7ec3ded5
-    """)
-    GIVEN_MASKED_DB = bytearray.fromhex("""
-    ea600669f6f16b3a2ad05d4b6d9b23911c8cc432fddd8d34a68d88af
-    3d787b7eebf6cd1b720812086758ce56e24ab819ccd8fb5eedb1cae9
-    f6f895667d7f89d0454b828777ecabc040a649c8956e78ec1c721370
-    663065cbc343deabad9eb6f2aceab6bfed5bea6543aa3672cddf915c
-    5b564848f4e6ec
-    """)
-    GIVEN_MASK_FOR_SEED = bytearray.fromhex("713162084a4e0e6d ")
-    GIVEN_MASKED_SEED = bytearray.fromhex("db2040f6425bb082")
     assert result[0] == GIVEN_MASKED_SEED, "is\n%s\ninstead of\n%s" % (result[0].hex(), GIVEN_MASKED_SEED.hex())
     assert result[1] == GIVEN_MASKED_DB, "is\n%s\ninstead of\n%s" % (result[1].hex(), GIVEN_MASKED_DB.hex())
 
-def rsa_oaep(ha: bytearray, m: bytearray):
+def rsa_oaep(ha: bytearray, m: bytearray, verbose: bool, seed: int = random.randint(0, 2**64 - 1)):
     # generate a seed
-    seed = random.randint(0, 2**64 - 1)
+    assert calclen(seed) == 8, "seed is wrong length: %d" % calclen(seed)
-    seed = bytearray(seed.to_bytes(calclen(seed), 'big'))
+    l_seed: bytearray = bytearray(seed.to_bytes(calclen(seed), 'big'))
     # build the message
     block: bytearray = bytearray(0)
     assert len(block) == 0
+    maxlen = calclen(GIVEN_PUB_KEY[0]) - 1 - len(l_seed)
     curlen = 0
     curlen += len(ha)
     curlen += len(m)
     block += ha
-    block += bytearray(calclen(GIVEN_PUB_KEY[0]) - curlen)
+    block += bytearray(maxlen - curlen - 1)
+    block += bytearray(0x01.to_bytes())
     block += m
 
-    assert len(block) == calclen(GIVEN_PUB_KEY[0]), "curlen:\n%s\nmodlen:\n%s" % (curlen, calclen(GIVEN_PUB_KEY[0]))
+    assert len(block) == maxlen
-    result = rsa_oaep_inner(seed, block)
+    if verbose:
+        print("block:\n%s" % block.hex())
+    # in this case
+    assert block == GIVEN_DB, "is\n%s\ninstead of\n%s" % (block.hex(), GIVEN_DB.hex())
+    assert type(l_seed) == bytearray
+    result = rsa_oaep_inner(seed=l_seed, block=block, verbose=verbose)
+    if verbose:
         print()
         print(result[0].hex())
         print(result[1].hex())
         print()
     return bytearray(1) + result[0] + result[1]
 
+def test_rsa_oaep():
+    r = rsa_oaep(bytearray(0), GIVEN_MSG, True, GIVEN_SEED)
+    assert r == GIVEN_OAEP
+    print(r)
+
+
 def main():
+    parser = argparse.ArgumentParser(prog="oaep-rsa", description='A hacky Implementation of rsa-oaep')
+    parser.add_argument('-m', '--message', type=str, metavar="MSG",
+                    help='the message of the oaep')
+    parser.add_argument('-rs', '--random-seed', action="store_true",
+                    help='a random seed')
+    parser.add_argument('-s', '--seed', type=int,
+                    help='a custom seed')
+    parser.add_argument('-a', '--hashed-data', type=str,
+                    help='append some auth hashed stuff')
+    parser.add_argument('-v', '--verbose', action="store_true",
+                    help='append some auth hashed stuff')
+    parser.add_argument('-t', '--test', action="store_true",
+                    help='perform tests')
+    args = parser.parse_args()
+
+    if args.test:
+        test_rsa_oaep()
+        test_rsa_oaep_inner()
+        exit()
+    if args.hashed_data:
+        ha = bytearray.fromhex(args.hashed_data)
+    else:
         ha = bytearray(0)
+    if args.message:
+        m = bytearray.fromhex(args.message)
+    else:
         m = bytearray.fromhex("466f6f62617220313233343536373839")
-    r = rsa_oaep(ha, m)
+    if args.seed:
-    print("final:\n%s" % r.hex())
+        seed: int = args.seed
+        r = rsa_oaep(ha, m, args.verbose, seed)
+    elif args.random_seed:
+        seed = random.randint(0, 2**64 - 1)
+        r = rsa_oaep(ha, m, args.verbose, seed)
+    else:
+        seed = GIVEN_SEED
+        r = rsa_oaep(ha, m, args.verbose, seed)
+    print("result:\n%s" % r.hex())
 
 if __name__ == "__main__":
     main()