WEEKDAY CHALLENGE: RSA Modular Exponentiation

Bree Kagwe

19d • ⚔️ Challenges

⚠️!!SPOILERS IN COMMENTS!!⚠️

🔑 KEY RULE: Upload your answer in PDF only, raw spoilers will be deleted.

PS: Don't forget to add comments in your code.

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All operations in RSA involve modular exponentiation.

Modular exponentiation is an operation that is used extensively in cryptography and is normally written like: 210mod 17210mod17

You can think of this as raising some number to a certain power (210=1024210=1024), and then taking the remainder of the division by some other number (1024mod 17=41024mod17=4). In Python there's a built-in operator for performing this operation: pow(base, exponent, modulus).

In RSA, modular exponentiation, together with the problem of prime factorisation, helps us to build a "trapdoor function". This is a function that is easy to compute in one direction, but hard to do in reverse unless you have the right information. It allows us to encrypt a message, and only the person with the key can perform the inverse operation to decrypt it.

To grab the flag, find the solution to 10117mod 2266310117mod22663

HERE'S YOUR TERMINAL (if applicable)

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Goodluck.

~ aScriptKiddie

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WEEKDAY CHALLENGE: RSA Modular Exponentiation