echo "This is a confidential message." > message.txt
openssl enc -aes-256-cbc -salt -pbkdf2 -in message.txt -out message.enc
openssl enc -aes-256-cbc -salt -pbkdf2 -in message.txt -out message.enc
xxd message.enc
openssl enc -d -aes-256-cbc -pbkdf2 -in message.enc -out message.dec.txt


openssl genpkey -algorithm RSA -out receiver-private.pem -pkeyopt rsa_keygen_bits:2048
openssl pkey -in receiver-private.pem -pubout -out receiver-public.pem
openssl pkey -in receiver-private.pem -text -noout
openssl pkey -pubin -in receiver-public.pem -text -noout
echo "Meet me in the cyber lab at 10." > message.txt
openssl pkeyutl -encrypt -pubin -inkey receiver-public.pem -in message.txt -out message.enc -pkeyopt rsa_padding_mode:oaep
openssl pkeyutl -decrypt -inkey receiver-private.pem -in message.enc -out message.dec.txt -pkeyopt rsa_padding_mode:oaep