basic summary:
#!/bin/sh openssl aes-256-cbc -a -salt -pass "pass:$2" -in $1 -out $1.enc echo "openssl aes-256-cbc -d -a -pass \"pass:XXX\" -in $1.enc -out $1"
make this into a simple script e.g. encode.sh wich you call with encode.sh file_to_encrypt "and_passphrase_here" and then you’re good to go. the output of the script tells you how to decrypt it… of course where XXX is said you ‘ve to tell the other to enter the right passphrase… obviously through another channel (just in case someone is listening).