How does the concept of a multiplicative inverse apply in modular arithmetic, and why is it important for decryption in ciphers like the Affine Cipher?
Wednesday, 12 June 2024
by EITCA Academy
The concept of a multiplicative inverse in modular arithmetic is fundamental to various applications within number theory and cryptography. Modular arithmetic, often referred to as clock arithmetic, involves numbers wrapping around upon reaching a certain value, known as the modulus. In this system, an integer has a multiplicative inverse modulo if the product is congruent
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, History of cryptography, Modular arithmetic and historical ciphers, Examination review
Tagged under:
Affine Cipher, Cryptography, Cybersecurity, Decryption, Modular Arithmetic, Multiplicative Inverse
Why is it necessary for the key (A) in the Affine Cipher to be coprime with the modulus 26, and what are the implications if it is not?
Wednesday, 12 June 2024
by EITCA Academy
The Affine Cipher is a type of monoalphabetic substitution cipher that utilizes mathematical operations to encrypt and decrypt messages. The encryption process in the Affine Cipher involves two keys, typically denoted as and , and follows the formula: where represents the encrypted letter, is the numerical equivalent of the plaintext letter (with ),
- Published in Cybersecurity, EITC/IS/CCF Classical Cryptography Fundamentals, History of cryptography, Modular arithmetic and historical ciphers, Examination review
Tagged under:
Affine Cipher, Cryptography, Cybersecurity, Decryption, Encryption, Modular Arithmetic