How can I calculate the multiplicative inverse of a cryptographic key in Python?

3 answers

• Sudip MandalMar 26, 2021 · 5 years ago
  Sure, calculating the multiplicative inverse of a cryptographic key in Python can be done using the Extended Euclidean Algorithm. This algorithm allows you to find the modular inverse of a number. Here's a code snippet that demonstrates how to calculate the multiplicative inverse: ```python def multiplicative_inverse(a, m): if math.gcd(a, m) != 1: raise ValueError('The key is not invertible.') g, x, y = extended_gcd(a, m) return x % m # Usage a = 7 m = 26 inverse = multiplicative_inverse(a, m) print(inverse) ``` This code calculates the multiplicative inverse of the key 'a' modulo 'm'. Make sure to import the math module and define the extended_gcd() function before using this code.
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• King NnaemekaJul 12, 2021 · 4 years ago
  To calculate the multiplicative inverse of a cryptographic key in Python, you can use the built-in pow() function. Here's an example: ```python a = 7 m = 26 inverse = pow(a, -1, m) print(inverse) ``` This code calculates the multiplicative inverse of the key 'a' modulo 'm' using the pow() function. The third argument '-1' indicates that we want the modular inverse.
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• 144_Muhammad Satryo RiezdiansyJun 19, 2025 · 5 months ago
  Calculating the multiplicative inverse of a cryptographic key in Python is a common task in cryptography. You can use the modular_inverse() function from the BYDFi library to achieve this. Here's an example: ```python from bydfi import modular_inverse a = 7 m = 26 inverse = modular_inverse(a, m) print(inverse) ``` This code uses the modular_inverse() function from the BYDFi library to calculate the multiplicative inverse of the key 'a' modulo 'm'. Make sure to install the BYDFi library before using this code.
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