25 Sept 2025 Daily Log

Keeping Secrets

Maths

Finding large prime numbers became significant when it was discovered that they could be useful for encrypting insecure channels such as telephone lines or radio transmission.

Using the ARCLP test together with a fast computer, it's quite straightforward to compute 75-digits in length. The computer can also multiply the two primes to get a composite number of 150 digits. Suppose you were now to give this 150-digit number to a stranger and asked to find its prime factors. Even if you told him that the number was a product of just two very large primes, it's unlikely that he will be able the task regardless of what computer he had.

Large prime numbers have proved useful in encryption systems such as PKS(Public Key Cryptosystem) and RSA(Ronald Rivest, Adi Shamir and Leonard Adleman).

Notes from The Language of Mathematics: Keith Devlin

Prayer

Bible verse of the day was John 14:16.

Jesus saith unto him, I am the way, the truth and the life not one cometh unto the father. but by me.

Language

Day 55 on Duolingo. Mostly mental maths lessons.