Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/rsa/core.py: 20%

1# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu> 

2# 

3# Licensed under the Apache License, Version 2.0 (the "License"); 

4# you may not use this file except in compliance with the License. 

5# You may obtain a copy of the License at 

6# 

7# https://www.apache.org/licenses/LICENSE-2.0 

8# 

9# Unless required by applicable law or agreed to in writing, software 

10# distributed under the License is distributed on an "AS IS" BASIS, 

11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 

12# See the License for the specific language governing permissions and 

13# limitations under the License. 

14 

15"""Core mathematical operations. 

16 

17This is the actual core RSA implementation, which is only defined 

18mathematically on integers. 

19""" 

20 

21 

22def assert_int(var: int, name: str) -> None: 

23 if isinstance(var, int): 

24 return 

25 

26 raise TypeError("%s should be an integer, not %s" % (name, var.__class__)) 

27 

28 

29def encrypt_int(message: int, ekey: int, n: int) -> int: 

30 """Encrypts a message using encryption key 'ekey', working modulo n""" 

31 

32 assert_int(message, "message") 

33 assert_int(ekey, "ekey") 

34 assert_int(n, "n") 

35 

36 if message < 0: 

37 raise ValueError("Only non-negative numbers are supported") 

38 

39 if message > n: 

40 raise OverflowError("The message %i is too long for n=%i" % (message, n)) 

41 

42 return pow(message, ekey, n) 

43 

44 

45def decrypt_int(cyphertext: int, dkey: int, n: int) -> int: 

46 """Decrypts a cypher text using the decryption key 'dkey', working modulo n""" 

47 

48 assert_int(cyphertext, "cyphertext") 

49 assert_int(dkey, "dkey") 

50 assert_int(n, "n") 

51 

52 message = pow(cyphertext, dkey, n) 

53 return message