Re-encrypt attachments enables you to change the encryption on existing ZIP archives that you attach to an email message. The option is useful when you want to send or forward an archive that may be encrypted already but not for the people you want to send it to.
The Re-encrypt attachments option is set on the General page of Mail options. To use it, also turn on Zip attachments and Encrypt attachments on this page.
For example, if Re-encrypt attachments is set, you can attach an archive encrypted for Smith (and you) to a message for Jones, and PK Protect will enable you to re-encrypt the archive so that Jones can read it.
The option enables you to ensure that all file attachments you send are encrypted, including existing ZIP archives.
Note: Unless Re-encrypt attachments is on, PK Protect does not encrypt already existing archives that you attach to mail messages.
The options Zip attachments and Encrypt attachments only operate on file attachments that are not ZIP archives. ZIP archives are attached unchanged.
How the Option Works
When Re-encrypt attachments is on, PK Protect displays a dialog containing the following choices when you attach an existing ZIP archive to a mail message:
Option for attaching ZIP files
What it does
Re-encrypt .ZIP attachments for new e-mail recipients
Removes any encryption on files in each attached ZIP archive and re-encrypts the files according to current settings on the ZIP page or OpenPGP page of Security options. Encrypts and adds any other, non-ZIP file attachments to a separate ZIP file.
Send original .ZIP attachments inside a new encrypted .ZIP file
Adds all attached ZIP archives to a new ZIP container archive. Does not modify attached archives but encrypts container archive according to current settings on the ZIP page or OpenPGP page of Security options. Encrypts and adds any other, non-ZIP file attachments to the container archive.
This option is disabled (as redundant) if Encrypt message body is set.
Send original .ZIP attachments as is
This option lets you override the setting to re-encrypt. It attaches ZIP archives without re-encrypting them or putting them in a new ZIP archive. Adds any other, non-ZIP file attachments to a new archive. Encrypts them according to current settings on the ZIP page of Security options.
If an Archive Cannot Be Re-Encrypted
If you select the option to re-encrypt (the first row in the table above), PK Protect prompts you for any passphrases necessary to decrypt. If some files in a ZIP attachment cannot be decrypted (because they were not encrypted for you as a recipient or you don't know the passphrase), PK Protect gives you several options for dealing with that attachment:
Option if a ZIP attachment cannot be decrypted
What it does
Send original .ZIP file inside a new encrypted .ZIP file
Adds attached ZIP archive to a new ZIP container archive. Does not modify attached archive but encrypts container archive according to current settings on the ZIP page or OpenPGP page of Security options.
Send original .ZIP file as is
Attaches ZIP archive without re-encrypting it or putting it in a new container archive.
Send modified .ZIP file (the file was created but error(s) occurred)
Attaches partially re-encrypted ZIP archive even though it contains files that could not be decrypted. (This choice is disabled if the original archive could not be even partially re-encrypted.)