65 lines
3.1 KiB
HTML
65 lines
3.1 KiB
HTML
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<link rel='stylesheet' type='text/css' href='../css/style.css'>
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<title>PKI and E-mail Encryption - A Brief Explanation</title>
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</head>
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<body>
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<center><h1>PKI and E-mail Encryption - A Brief Explanation</h2></center>
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PKI stands for <cite>Public Key Infrastructure</cite>. PKI is Information
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Technology infrastructure that enables users of a basically unsecure public
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network (such as the Internet) to securely and privately exchange data through
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the use of a <a href=glossary.html#KEYS target=glossary>public and a private
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cryptographic key pair</a> that is obtained and shared through a
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<a href=glossary.html#CA target=glossary>trusted Authority</a>.
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<p>
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Public and private keys are like two halves of a single key. PKI encryption
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algorithms are designed such that a public key is used to encrypt or
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"lock" a message, and only the complementary private key can "unlock" that
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message.
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Think of a bank vault or safe that can only be unlocked by two individuals
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using two different but complementary keys. Neither of those keys can be used
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by itself to unlock the vault.
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<p>
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In practice, individuals wishing to exchange encrypted e-mail
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will agree to mutually trust one or more <a href=glossary.html#CA target=glossary>
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Certificate Authorities(CA)</a> by downloading and installing each trusted Authority's
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<a href=glossary.html#ROOT-CERT target=glossary>root certificate</a> on their computers.
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They will each obtain their own personal
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<a href=glossary.html#CERTIFICATE target=glossary>digital certificate</a>
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from a trusted Certificate Authority, and install them on their
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respective computers.
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Because they mutually trust the Certificate Authorities, they trust each other's
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digital certificates. More specifically, they trust the
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<a href=glossary.html#KEYS target=glossary>public keys</a> contained within
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their personal digital certificates which have been
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<a href=glossary.html#SIGNATURE target=glossary>digitally signed</a> by a
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trusted Certificate Authority.
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They will then exchange their trusted public keys by sending each other
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digitally signed e-mail messages. Once each party has the other's public key,
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they may exchange trusted and encrypted messsages.
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<p>
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Public key exchange and encryption is like exchanging notarized documents.
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One trusts a notarized document because a trusted third party, the Notary
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Public, has signed it. The Certificate Authority is the Notary Public, and
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the public keys are the documents.
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<p>
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Remember, having a personal digital certificate alone does <strong>not</strong>
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give one the ability to send encrypted e-mail to others, but only allows the
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<strong>receipt</strong> of encrypted e-mail. PKI is a cooperative encryption
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standard. Both parties who are exchanging encrypted messages must have
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personal digital certificates, they must trust the Certificate Authority
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which issued the other persons certificate, and they must exchange
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public keys with each other, as described above.
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<p>
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The process of installing certificates and exchanging public keys is dependent
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upon the e-mail application one uses, and is beyond the scope of this document.
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</body>
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</html>
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