- When Alice starts the app, it generates a private and public key.
- Alice’s private key never leaves her phone. The app stores the public key on a server, available to all who send her message.
- When Bob writes to Alice, the app retrieves her public key. Then uses it to encrypt his message that only Alice’s private key can decrypt.
- The app sends an encrypted file through the server to Alice.
- Alice receives the file. The app uses her private key to decrypt the message.
The correlation between prime numbers and encryption
11 x 17 = 187 means the product of 2 large random prime numbers is the backbone of encryption.
So cracking the encryption means figuring out the two factors. Using brute force takes decades with today’s computers. If a hacker knows the two numbers (private key), it’ll take him a split second to crack it.
17,425,170 means the number of digits in the most significant prime number.
The integers make up your public key in part by calculating the number that shares no common factors. Also, they are less than the product of the two prime numbers. That’s why encryption confuses the attacker or hacker.