compressWithPassWord.md

Securely encrypted ZIPs right from contextual menu in Mac OS

Run the following simple oneliner to download and "install" the service:

curl -L https://dl.dropbox.com/s/wpxbnm8y6gb6l32/compressWithPassword.tar.gz | tar zx -C ~/Library/Services/

And while selecting files or folders in Finder you will find the new option

Services > Compress with password

Note: as of today will only work with one file or directory at a time.

💥

Implementation details

Check passwordWithExpect.sh to see the script that this service runs.

Nothice that I didn't use zip's --password parameter that would entail the dangers of command logging. Instead, I used expect to pass the password directly to the zip function. Given that Automator services do not support expect scripts, I had to wrap it on a bash script. For the curious minds, -f - defines that expect will be using standard input. Then the following "$@ allows to send the function parameters to expect that will be extracted with [lindex $argv <number>]. Other than that you know what << means, and everything between ! will be the input sent to expect. Awesome, right?

passwordWithExpect.sh

doit (){
	expect -f - "$@" <<\!
	set timeout -1
	set prompt {$ }
	set password [lindex $argv 0]

	#spawn the command
	spawn zip -re [lindex $argv 1] [lindex $argv 2]

	# Look for passwod prompt (twice)
	expect "*?assword:*"
	send "$password\r"
	expect "*?assword:*"
	send "$password\r"

	expect $prompt
!
}

cd $(dirname "$2")
doit "$1" EncryptedArchive.zip "$(basename "$2")"