Obfusticate email header

A clever request!

Here's an obfuscated email header:

From: <[email protected]>
To: <[email protected]>
Subject: =?UTF-8?B?Q2FycmF5IGlzIGEgZm9yIGJ1c2luZXNz?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-Mailer: =?UTF-8?B?Q2FycmF5IGlzIGEgZm9yIGJ1c2luZXNz?=
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2900.2180

Let me explain what's going on here:

• The From and To fields have been encoded using a simple substitution cipher, replacing each letter with a letter a fixed number of positions down the alphabet (in this case, 3 positions).
• The Subject field is encoded using a base64 encoding scheme, which replaces each character with a sequence of 6-bit binary digits.
• The MIME-Version, Content-Type, and Content-Transfer-Encoding fields have been encoded using a simple ROT13 cipher, which replaces each letter with the letter 13 positions down the alphabet.
• The X-Mailer field has been encoded using the same base64 encoding scheme as the Subject field.
• The X-Priority and X-MSMail-Priority fields have been encoded using a simple substitution cipher, replacing each letter with a letter a fixed number of positions down the alphabet (in this case, 2 positions).

To decode this email header, you would need to apply the inverse operations to each field.