ts-cms-ep-sfx Files

This release incorporates two important technical updates:

1. Since AES-256-GCM is used, the more appropriate AuthEnvelopedData (RFC 5083) structure is used rather than EnvelopedData.
2. Now, AES-256-CBC with CMS key wrapping (RFC 3211, §2.3) is used for encrypting the PWRI field, instead of using AES-256-GCM.

The result of these changes is a more correct implementation of CMS. This has the added benefit that the output file can be recovered with other tools, such as OpenSSL:

:::sh
# `/path/to/encryptedoutput.example.html` is the file generated by this tool,
# `/path/to/encryptedoutput.example` is where the decrypted file will be saved
printf 'Password: ' && read password && openssl cms -decrypt -pwri_password "$password" -inform PEM -in /path/to/encryptedoutput.example.html -out /path/to/encryptedoutput.example