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c0da015b7d
* diffie doctest * fix ut * update doctest --------- Co-authored-by: Harsha Kottapalli <skottapalli@microsoft.com>
54 lines
1.5 KiB
Python
54 lines
1.5 KiB
Python
from __future__ import annotations
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def find_primitive(modulus: int) -> int | None:
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"""
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Find a primitive root modulo modulus, if one exists.
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Args:
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modulus : The modulus for which to find a primitive root.
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Returns:
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The primitive root if one exists, or None if there is none.
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Examples:
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>>> find_primitive(7) # Modulo 7 has primitive root 3
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3
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>>> find_primitive(11) # Modulo 11 has primitive root 2
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2
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>>> find_primitive(8) == None # Modulo 8 has no primitive root
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True
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"""
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for r in range(1, modulus):
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li = []
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for x in range(modulus - 1):
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val = pow(r, x, modulus)
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if val in li:
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break
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li.append(val)
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else:
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return r
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return None
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if __name__ == "__main__":
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import doctest
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doctest.testmod()
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prime = int(input("Enter a prime number q: "))
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primitive_root = find_primitive(prime)
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if primitive_root is None:
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print(f"Cannot find the primitive for the value: {primitive_root!r}")
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else:
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a_private = int(input("Enter private key of A: "))
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a_public = pow(primitive_root, a_private, prime)
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b_private = int(input("Enter private key of B: "))
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b_public = pow(primitive_root, b_private, prime)
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a_secret = pow(b_public, a_private, prime)
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b_secret = pow(a_public, b_private, prime)
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print("The key value generated by A is: ", a_secret)
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print("The key value generated by B is: ", b_secret)
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