GFI MailEssentials 
WorldSecure 
PGP Extension 
ARCryptoMail 
CryptoEx for MS Exchange 
Mark Wilson Classify 
Signed, Sealed, Delivered 
MailSecure Plug-in 
Entrust/Express 
ExSign 
PGP for Personal Privacy 
Ascom IDEA@exchange 
RPK InvisiMail 
TrustedMIME 
Secure Exchange Servers 
Krypto 
Boldon James SAFEmail.mil 
TFS Encryption 
S/MIME Everywhere 
VeriSign 
Compaq Exchange (SE) 
Encryption Plus 
TFS Secure Messaging - Server 
Mail Vault 
Policy Patrol 
Arcot WebFort 
MailRecall 
securiQ 
eFilter 
IronMail 
iMira Screening 
SuperScout 
eMailTrackerPro