Complete Git Guide: Understand and Master Git and GitHub - More details on hash collision probability (OPTIONAL)

The lecture delves into hash collision and probability theory, correcting previous misconceptions about hash collisions. It uses dice games to explain probability concepts and extends these ideas to understand the probability of hash collisions in Git repositories. The lecture concludes with a formula to calculate the probability of hash collisions, emphasizing that such events are extremely rare.

What is a hash collision?

• When two files have different hashes

• When two files have the same hash

• When a file has no hash

• When a file has multiple hashes

What is the probability of getting the same number on two dice?

• 1/3

• 1/12

• 1/6

• 1/36

How many successful outcomes are there for getting the same number on two dice?

• 24

• 12

• 18

• 6

What is the probability of getting the same number on three dice?

• 1/216

• 1/36

• 1/6

• 1/3

What is the formula for calculating the probability of the same number on N dice?

• 1/6^n

• 1/6^(n-1)

• 1/6^(n+1)

• 1/6^2

What is a factorial?

• A subtraction of numbers

• A division of numbers

• A product of numbers from 1 to n

• A sum of numbers

How does the probability of getting the same number change with more dice?

• It becomes zero

• It remains the same

• It increases

• It decreases

What is the probability of a hash collision in a Git repository?

• Very low

• Moderate

• Impossible

• Very high

What does the SHA-1 hash collision formula calculate?

• The number of files in a repository

• The probability of different hashes

• The exact hash value

• The probability of the same hash for different files

Why is the probability of hash collision in Git repositories considered negligible?

• Because of the large number of possible hash values

• Because Git automatically prevents collisions

• Because SHA-1 is infallible

• Because files are always unique