Interoperability of S/Mime and PGP encrypted email products

This chart is current as of November 10, 1998 and as such is woefully outdated. It contains information on the various features and interoperability of different secure email products. There are two different and incompatible security mechanisms: Secure MIME (S/Mime) and Pretty Good Privacy (PGP). Each product has a range of different features, as show in the table below.

There are two different categories of products: the first set contains stand-alone email client software products. Many of these products, such as Outlook and Notes, require both client and server components to perform encryption functions. The second set contains plug-ins for existing email products, and we indicate the products supported by each vendor. Note that interoperability isn't guaranteed across a single vendor's product line necessarily.

S/MIME and PGP Products

S/Mime or PGP Clients Supported Trust individual certs Trust CA root certs Send/receive clear/opaque msg. Key encrption schema
Win 3.1 Win 32 Mac
Microsoft Outlook Express S/Mime No Yes No Yes (1) Yes S/R C; S only O RC2 (40, 64, 128)
Microsoft Outlook 98 (7) S/Mime No Yes Yes Yes (1) Yes S/R C/O RC2 (40, 64, 128)
Netscape Messenger 4.5 S/Mime Yes Yes Yes Yes Yes S/R C; R only O RC2 (40, 64, 128)
OpenSoft ExpressMail 2.5 S/Mime Yes Yes No No No S/R C/O (5) RC2 (40, 64, 128, 255)
Lotus Notes S/Mime Coming in R5 Yes (1)      
Cyrusoft Mulberry PGP No Yes Yes Yes N/A S/R C only DH

S/MIME and PGP Plug-ins

S/Mime or PGP Clients Supported Trust individual certs Trust CA root certs Send/receive clear/opaque msg. Key encrption schema Products supported
Win 3.1 Win 32 Mac
WorldTalk WorldSecure Client 2.2 S/Mime Yes Yes No Yes No S/R C/O (5) (6) RC2 (40, 64, 128, 255) Eudora, Outlook
Labcal Technologies' IsoShield/Mail S/Mime Yes Yes No Yes (1) No S/R C/O RC2 (40, 64) Notes
LJL Enterprises' ArmorMail S/Mime Yes Yes No Yes Yes S/R C; R only O (5) RC4 (40, 128) (3) MS Mail, cc:Mail, Outlook, Notes, Eudora
Baltimore Mail Secure S/Mime Yes Yes No Yes Yes Limited (2) (5) RC2 (40, 64, 128) Eudora, Outlook
Novell Groupwise w/Entrust S/Mime No Yes No Yes Yes S/R C/O RC2 (40, 64, 128) Groupwise
PGP for Business Privacy (4) PGP No Yes Yes Yes N/A S/R C only DH Eudora, Exchange, Outlook, Claris Emailer
Novell Groupwise w/ PGP PGP No Yes No Yes N/A S/R C only DH Groupwise
Entrust Lite S/Mime Yes Yes Yes Yes Yes S/R C/O RC2 (40, 64, 128), DH MS Mail, Outlook, cc:Mail, QuickMail

Notes:

(1) Certificates are stored in user's own address book.

(2) Can exchange opaque signed messages only with Outlook.

(3) LJL plans on offering DH support in future products.

(4) There are several PGP versions available from Network Associates and others, including business and personal products, those available with and without support for earlier RSA encryption.

(5) Sends signed messages in p7m format.

(6) Eudora plug-in can't process HTML-encoded messages, Outlook plug-in can't receive signed messages.

(7) Outlook 97 has no S/Mime support, this was added for Outlook 98. Outlook for Windows 3.1 does not have S/Mime support. For Outlook for Macintosh, you will need to apply Exchange Server 5.5 Service Pack 1.

copyright 1998 David Strom Inc.