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09 Security and Cryptography

Exercises

  1. Entropy

  2. four concatenations: log2(10^20)≈66.4

  3. 62 possibilities > log2(62^8)≈47.6
  4. previous one with larger entropy
  5. 3*10^8 years and 692 years
  6. bash % sha256sum debian-mac-11.2.0-amd64-netinst.iso | shasum --algorithm 256 --check debian-mac-11.2.0-amd64-netinst.iso: OK
  7. bash $ openssl aes-256-cbc -salt -in secret.txt -out secret.enc.txt enter aes-256-cbc encryption password: Verifying - enter aes-256-cbc encryption password: $ openssl aes-256-cbc -d -in secret.enc.txt -out secret.dec.txt enter aes-256-cbc decryption password: $ cmp secret.txt secret.dec.txt | echo $? 0