Enter Modular Exponentiation

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Solve 5¹⁵ mod 23 using:

Modular exponentiation

Build an algorithm:

n is our exponent = 15

y = 1 and u ≡ 5 mod 23 = 5

See here

n = 15 is odd

Since 15 is odd, calculate (y)(u) mod p

(y)(u) mod p = (1)(5) mod 23

(y)(u) mod p = 5 mod 23

5 mod 23 = 5
Reset y to this value

Determine u² mod p

u² mod p = 5² mod 23

u² mod p = 25 mod 23

25 mod 23 = 2
Reset u to this value

Cut n in half and take the integer

15 ÷ 2 = 7

n = 7 is odd

Since 7 is odd, calculate (y)(u) mod p

(y)(u) mod p = (5)(2) mod 23

(y)(u) mod p = 10 mod 23

10 mod 23 = 10
Reset y to this value

Determine u² mod p

u² mod p = 2² mod 23

u² mod p = 4 mod 23

4 mod 23 = 4
Reset u to this value

Cut n in half and take the integer

7 ÷ 2 = 3

n = 3 is odd

Since 3 is odd, calculate (y)(u) mod p

(y)(u) mod p = (10)(4) mod 23

(y)(u) mod p = 40 mod 23

40 mod 23 = 17
Reset y to this value

Determine u² mod p

u² mod p = 4² mod 23

u² mod p = 16 mod 23

16 mod 23 = 16
Reset u to this value

Cut n in half and take the integer

3 ÷ 2 = 1

n = 1 is odd

Since 1 is odd, calculate (y)(u) mod p

(y)(u) mod p = (17)(16) mod 23

(y)(u) mod p = 272 mod 23

272 mod 23 = 19
Reset y to this value

Determine u² mod p

u² mod p = 16² mod 23

u² mod p = 256 mod 23

256 mod 23 = 3
Reset u to this value

Cut n in half and take the integer

1 ÷ 2 = 0

Because n = 0, we stop

We have our answer

Final Answer

5¹⁵ mod 23 ≡ 19

You have 1 free calculations remaining

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What is the Answer?

5¹⁵ mod 23 ≡ 19

How does the Modular Exponentiation and Successive Squaring Calculator work?

Free Modular Exponentiation and Successive Squaring Calculator - Solves xⁿ mod p using the following methods:
* Modular Exponentiation
* Successive Squaring
This calculator has 1 input.

What 1 formula is used for the Modular Exponentiation and Successive Squaring Calculator?

Successive Squaring I = number of digits in binary form of n. Run this many loops of a² mod p

For more math formulas, check out our Formula Dossier

What 6 concepts are covered in the Modular Exponentiation and Successive Squaring Calculator?

exponent

The power to raise a number

integer

a whole number; a number that is not a fraction
...,-5,-4,-3,-2,-1,0,1,2,3,4,5,...

modular exponentiation

the remainder when an integer b (the base) is raised to the power e (the exponent), and divided by a positive integer m (the modulus)

modulus

the remainder of a division, after one number is divided by another.
a mod b

remainder

The portion of a division operation leftover after dividing two integers

successive squaring

an algorithm to compute in a finite field

Example calculations for the Modular Exponentiation and Successive Squaring Calculator

Modular Exponentiation and Successive Squaring Calculator Video

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