starts @ 24:30

https://youtu.be/Q7fgsbO0Pmg?si=01nXFKq88LiZ13r_&t=1488

after studying SPNs and Feistel Cipher Structure, you have 2 good ways to start doing your own encryption algorithm at home, yay!

so - in 1977 - some people created an encryption algorithm and called it: Data Encryption Standard (DES)

DES History

• IBM developed Lucifer cipher
  • by team led by Feistel in late 60’s
  • used 64-bit data blocks with 128-bit key
• then redeveloped as a commercial cipher with input from NSA and others
• in 1973 NBS issued request for proposals for a national cipher standard
• IBM submitted their revised Lucifer which was eventually accepted as the DES

in DES:

• Data are encrypted in 64-bit blocks using a 56-bit key
• The algorithm transforms 64-bit lnput in a series of steps into a 64-bit output
• The same steps, with the same key, are used to reverse the encryption

ok this doesn’t look good

DES is so complicated, watch the video and I believe the best way to get it is to implement it with your hands