Encrypt a message with s/mime and send key password back

autoecrypt.sh

alias openssl=/Users/yottatsa/.local/homebrew/Cellar/openssl/1.0.2l/bin/openssl

conf () {
	echo "
[ req ]
default_bits           = 4096
distinguished_name     = req_distinguished_name
prompt                 = no

[ req_distinguished_name ]
CN                     = $1
emailAddress           = $1
"
}

ca () {
	echo "
[ usr_cert ]
basicConstraints = CA:TRUE"
}

usr_cert () {
	echo "
[ usr_cert ]
basicConstraints = CA:FALSE
authorityKeyIdentifier = keyid
subjectKeyIdentifier = hash
keyUsage = critical, digitalSignature, keyEncipherment
extendedKeyUsage = critical, emailProtection
subjectAltName = email:copy
authorityKeyIdentifier = keyid
subjectKeyIdentifier = hash"
}

generatesend () {
	if ! [ -f $1.crt ]
	then 
		openssl rand -hex 16 > $1.password
		openssl req -batch -newkey rsa:4096 -keyout $1.key -out $1.csr -passout file:$1.password -config <(conf $1; usr_cert)
		openssl req -new -x509 -days 7 -key $1.key -out $1_ca.crt -passin file:$1.password -batch -config <(conf $1; ca)
		openssl x509 -req -days 365 -in $1.csr -CA $1_ca.crt -CAkey $1.key -set_serial 1 -out $1.crt -setalias "Self Signed S/MIME for $1" -addtrust emailProtection -addreject clientAuth -addreject serverAuth -trustout -passin file:$1.password
		openssl pkcs12 -export -in $1.crt -certfile $1_ca.crt -inkey $1.key -out $1.p12 -name "Self Signed S/MIME for $1" -passin file:$1.password -passout file:<(cat $1.password) -aes256
		(echo Content-Transfer-Encoding: base64; echo "Content-Disposition: attachment;filename=\"$1.p12\""; echo "Content-Type: application/x-pkcs12;name=\"$1.p12\""; echo; base64 -b 64 < $1.p12) > $1_p12.mime
		(echo "Subject:"; echo "MIME-Version: 1.0"; echo; cat $1.password) |\
		openssl smime -sign -signer $1.crt -inkey $1.key -passin file:$1.password  |\
		openssl smime -encrypt -aes256 -from $1 -to $sender -subject "Password for $1" -out $1_password.eml $cert
		rm -f $1_ca.crt $1.csr $1.key $1.password $1.p12
	fi
	(
	echo From: $sender
	echo To: $1
	echo "MIME-Version: 1.0"
	echo "Content-Type: multipart/mixed;boundary=\"mime\""
	echo "Subject: encrypted"
	echo
	echo This is encrypted message
	echo 
	echo "--mime"
	openssl smime -encrypt -aes256 -in in.eml $1.crt
	echo "--mime"
	cat $1_p12.mime
	echo
	echo "--mime--"
	) > $1.eml
}

sender=$1
shift
cert=$1
shift
tee > in.eml
for email
do
	generatesend $email email.txt
done
rm -f in.eml