== Secure Multipurpose Internet Mail Extension (S/MIME) ==

== Secure Multipurpose Internet Mail Extension (S/MIME) ==

The standard MIME protocol extends the Simple Mail Transfer Protocol (SMTP) to enable the inclusion of non-ASCII (i.e non-plain text) attachments such as binary, photo and audio files in email messages.  

The standard MIME protocol extends the Simple Mail Transfer Protocol (SMTP) to enable the inclusion of non-ASCII (i.e. non-plain text) attachments such as binary, photo and audio files in email messages.  

The secure version of MIME, known as S/MIME, was developed by RSA Data Security and uses the X.509 certificate format to allow for the encrypted email transmission of data over public networks. S/MIME uses 40-bit RC2 and #DES based encryption and is supported by most modern email client applications.

The secure version of MIME, known as S/MIME, was developed by RSA Data Security and uses the X.509 certificate format to allow for the encrypted email transmission of data over public networks. S/MIME uses 40-bit RC2 and #DES based encryption and is supported by most modern email client applications.

== Dealing with Spam Email ==

== Dealing with Spam Email ==

Whilst it is impossible to arrive at exact numbers, it is widely believed that spam email now accounts for as much as 40% of all traffic on  the internet. The time employees spend deleting unwanted spam messages is believed to cost businesses in the United States alone in excess of $2 billion. a year in terms of lost productivity.

Whilst it is impossible to arrive at exact numbers, it is widely believed that spam email now accounts for as much as 40% of all traffic on  the internet. The time employees spend deleting unwanted spam messages is believed to cost businesses in the United States alone in excess of $2 billion a year in terms of lost productivity.

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Clearly spam email messages are a serious issue which must be addressed by system administrators and IT security employees. A number of solutions to the problem are available but none, unfortunately provide 100% certainty of either eliminating all spam, or guaranteeing that legitimate messages will not be incorrectly categorized as spam.

Clearly spam email messages are a serious issue which must be addressed by system administrators and IT security employees. A number of solutions to the problem are available but none, unfortunately, provide 100% certainty of either eliminating all spam, or guaranteeing that legitimate messages will not be incorrectly categorized as spam.

One solution is to subscribe to ''email blacklists''. These are services which maintain a registry of known spam senders which can be used to isolate spam messages. Unfortunately many spammers send email using the open relays of legitimate email servers thereby disguising their true identity and limiting the usefulness of email blacklists.

One solution is to subscribe to ''email blacklists''. These are services which maintain a registry of known spam senders which can be used to isolate spam messages. Unfortunately many spammers send email using the open relays of legitimate email servers thereby disguising their true identity and limiting the usefulness of email blacklists.