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+======Simple Encrypted Data======
+The client always offers a basic obfuscating encryption cipher called SED
+(Simple Encrypted Data).
+SED is an unbuffered ECB cipher that uses a variable length key.
+Each byte in the input string is XORed with each corresponding byte in the
+cipherkey and XORed with a "mix" value, whose initial value is 0.
+After each byte, the "mix" value is XORed with the initial value of the byte.
+Thus, the mix value at each position is the XOR of every plaintext byte
+previously analyzed.
+When the end of the cipherkey is reached, it goes back to the beginning.
+Thus, longer passkeys yield better results.  Passkeys longer than the
+plaintext do not yield any additional benefit.  Because the same passkey
+is used each time, this is an ECB cipher.
+======Examples:======
+If you ciphered the string "testing" with the passkey "hello":
+Byte 1:  MIX = 0x00, BYTE = 0x74, KEY = 0x0x68,
+	 NEW BYTE == MIX ^ BYTE ^ KEY = 0x1C
+         NEW MIX  == MIX ^ BYTE = 0x74
+Byte 2:  MIX = 0x74, BYTE = 0x65, KEY = 0x65,
+	 NEW BYTE == MIX ^ BYTE ^ KEY = 0x74
+	 NEW MIX  == MIX ^ BYTE = 0x11
+(...and so on)
+======Weaknesses:======
+SED is not a serious encryption scheme.  But it does obfuscate your data enough
+that you're not sending your messages in plaintext which frustrates server-side
+attempts to pattern match your conversations.  You should assume anyone who is
+interested in you could decrypt your messages, but since it's presumed most
+server-side surveilance is done by pattern matching plaintext, having a simple
+universal means to obfuscate your messages makes it not worth someone's bother
+to decrypt your messages just to pattern match them.
+Because the client does recursive CTCP handling, if you are using encryption
+with someone and you [[DCC SEND]] them a file, the CTCP DCC SEND offer will
+be encrypted, which is extremely helpful for thwarting server-side attempts
+to log all file transfers on the network.  (Yes, there have been networks that
+actually log all DCC SEND offers and send them to the government).  Not all
+other clients support this, however.