Math Problem Statement

solve the discrete logarithm with math : log 627 (608) for the prime p = 941

Solution

To solve the discrete logarithm log627(608)\log_{627}(608) modulo a prime p=941p = 941, we need to find an integer xx such that:

627x608 (mod 941)627^x \equiv 608 \ (\text{mod} \ 941)

This is a classical discrete logarithm problem. Solving it involves finding the exponent xx, and one of the methods to solve it is the baby-step giant-step algorithm, a time-efficient algorithm for discrete logarithms.

Steps to solve the discrete logarithm:

  1. Set the parameters:

    • The prime p=941p = 941, base g=627g = 627, and the result y=608y = 608.
    • We aim to solve gxy (mod 941)g^x \equiv y \ (\text{mod} \ 941).
  2. Apply the baby-step giant-step method:

    • Let m=94131m = \lceil \sqrt{941} \rceil \approx 31.
    • Break the problem into two steps: computing baby steps and giant steps.

Baby-step phase:

We compute and store all powers of the base 627627 for the first mm values:

Baby steps: {627jmod9410j<31}\text{Baby steps: } \{627^j \mod 941 \mid 0 \leq j < 31\}

Giant-step phase:

Now, for the giant steps, compute the modular inverses of powers of 627mmod941627^{-m} \mod 941 and compare to the baby-step list.

Compute and compare:

The first value of xx where the two lists match gives the solution.

Using these steps, we find the discrete logarithm xx. Let me calculate this for you!The solution to the discrete logarithm log627(608)\log_{627}(608) modulo 941941 is x=18x = 18. This means:

62718608 (mod 941)627^{18} \equiv 608 \ (\text{mod} \ 941)

Would you like a detailed breakdown of the baby-step giant-step method used, or do you have any further questions?

Here are 5 related questions you might explore:

  1. How is the baby-step giant-step algorithm derived?
  2. Why is Fermat's Little Theorem used to compute modular inverses?
  3. Can the discrete logarithm problem be solved efficiently for larger primes?
  4. What are some real-world applications of discrete logarithms in cryptography?
  5. How does the time complexity of the baby-step giant-step algorithm compare to brute force?

Tip: Modular arithmetic is widely used in cryptography, especially for encryption schemes like RSA and Diffie-Hellman key exchange.

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Math Problem Analysis

Mathematical Concepts

Number Theory
Modular Arithmetic
Discrete Logarithms

Formulas

g^x ≡ y (mod p)
m = ⌈√p⌉ (for baby-step giant-step algorithm)

Theorems

Baby-step Giant-step Algorithm
Fermat's Little Theorem (for computing modular inverses)

Suitable Grade Level

Undergraduate Level (or advanced high school for discrete mathematics)