Secure Email Script

We are looking for a simple email script that could send a email with the same content but with different attachments and receivers. We don't mean sending mass emails, only 1 email at a time is required. Here's what we do : 1. Login to a secure area to access the script. 2. Upload the attachment(Mostly under 1MB, pdf file). 3. Enter the receiver's email(Only 1 receiver). 4. Your script sends the email to the reciver. NOTE : 1. We want a extremely SECURE script, please write the code as secure as possible. 2. Email content must be in HTML, NOT plain text. 3. Email content will NOT be in English, so UTF-8 support is required. Escrow payment provided upon request, we need the script ready ASAP.