How Prime Numbers Keep the Internet Secure
summary
Shows a hands-on RSA implementation using Ruby and a tiny server: picks p=13, q=17, n=221, computes totient 192, chooses e=7 and brute-forces d as 55, then demonstrates encrypting to cipher 185 and decrypting back to 42 via curl and IRB. Explains why prime factorization of large (2–4k bit) n is infeasible (millions–billions of years on classical hardware), notes real-world use in TLS/SSH and weaknesses from developer mistakes and quantum attacks.
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chapters (13)
- 0:00Introduction
- 1:45What are Prime Numbers
- 4:19What are Encryption Functions
- 5:42Symmetric Encryption
- 6:47Asymmetric Encryption
- 11:50RSA History
- 14:21RSA Implementation
- 16:23Selecting the Value
- 17:37Creating the Private Key
- 20:51Encryption
- 22:18Encryption Decryption
- 24:58Can RSA be broken
- 26:12Prime factorization
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