The details of the content actually encrypted into a pkcs #7 enveloped object depend to some extent on the technology used. Some technologies will represent string data as UNICODE-encoded bytes, while others will simply use text data as ANSI data (one character per byte). This can cause confusion in the process of decryption or verifying signature pkcs #7 data.
The WSH vbs script DenvelopAll.vbs is a utility which demonstrates
one approach to decryption of enveloped pkcs #7 message files. This includes enveloped data
produced by CAPICOM EnvelopedData.Encrypt(), or encryption data blocks wrapped in S-MIME
format in S-MIME capable email clients. DenvelopAll.vbs has been tested with S-MIME
enveloped data from Outlook Express 6 and Netscape Messenger 4.7. DenvelopAll.vbs can also
decrypt binary der encrypted blocks (if ADODB is installed) containing arbitrary binary data.
Michel I. Gallant