+import json, hashlib
+
+def rsa_verify(message, signature, key):
+ from struct import pack
+ from hashlib import sha256
+ from sys import version_info
+ def b(x):
+ if version_info[0] == 2: return x
+ else: return x.encode('latin1')
+ assert(type(message) == type(b('')))
+ block_size = 0
+ n = key[0]
+ while n:
+ block_size += 1
+ n >>= 8
+ signature = pow(int(signature, 16), key[1], key[0])
+ raw_bytes = []
+ while signature:
+ raw_bytes.insert(0, pack("B", signature & 0xFF))
+ signature >>= 8
+ signature = (block_size - len(raw_bytes)) * b('\x00') + b('').join(raw_bytes)
+ if signature[0:2] != b('\x00\x01'): return False
+ signature = signature[2:]
+ if not b('\x00') in signature: return False
+ signature = signature[signature.index(b('\x00'))+1:]
+ if not signature.startswith(b('\x30\x31\x30\x0D\x06\x09\x60\x86\x48\x01\x65\x03\x04\x02\x01\x05\x00\x04\x20')): return False
+ signature = signature[19:]
+ if signature != sha256(message).digest(): return False
+ return True