Beyond E-Cipher

The E-Cipher (E: optimized for Efficiency) is a balance between too easy and too difficult an algorithm. It is just right, maximizing the product of the ease of implementation and the security achieved. If an algorithm is 20% easier but 50% less secure or 20% more secure while being 50% more difficult to implement, you get less bang for your buck and a lower efficiency. Also with greater complexity comes a greater possibility for mistakes (in a hand performed technique), tending toward failure to successfully communicate to the intended recipient and unsuitability to wearing a crown for efficiency.

Here are some Modified E-Cipher algorithms while, over emphasizing one way or the other, may be better suited than the standard official algorithm for certain situations. For these descriptions to make sense you have to have first read and understood the description of the

E-Cipher.

Too soft, Abridged for Extra Ease

Easy E-Cipher (EE-Cipher)

The E-Cipher done without a second ‘Pre’ key.

This version may be acceptable for most private communications, such as a letter or email where privacy or confidentiality is the issue but high security from professional attack is not a must.

Extra Easy E-Cipher (E3-Cipher)

The E-Cipher done without Pre-key or doing the Re-Keying operations.

This version may be well suited for personal communication at work, school, or public places, as well as short letters, and perhaps IR beamed messages where minimal security is needed and the information being transmitted is not of great significance.

Too hard, Extended for Greater Security

If you reuse your keys and there is a possibility of the plain-text from a message being compromised or predicted then a cryptanalyst could perform a plain text attack on your messages and possibly effectively determine the set of keys you are using; and thus any message sent using that key pair. For security against this you would use one of the variations which thwart plain-text attacks.

Double message Encryption E-Cipher (DE E-Cipher)

To do this one would start by encrypting the plain text message.

Then treat the obtained cipher text as if it were plain text, which had been connected to the end of the original text. So you continue using the current Cipher-Alphabet in its current state applying the encryption process to this appended text as if it had been the second half of the message in the first place. You then transmit only the second length of cipher text generated. Obviously this process will take twice as long.

To decrypt, you duplicate the provided cipher text on to the end of itself; decrypt as usual; take the resulting second half and start anew with it acting as the input cipher text to be decrypted.

Double character Substitution E-Cipher (DS E-Cipher)

To perform this addition substitution step: You line up the prekey alphabet, alone with the regular current cipher-alphabet, at the same position relative to an a-z alphabet. For letter substitution you first find a substitute letter in the prekey-alphabet which is aligned with the letter from the plain text which you are encoding, take that letter and continue as if it had been the plain text letter, finding what would be the proper cipher-alphabet substitution letter for it. This then becomes part of the cipher text output of the algorithm. Note there are no other operations (like shifting) between finding these two letter substitutions. [an example]

Further, to circumvent a minor weakness, if any keyed alphabet would begin with the letter ‘A’ move the ‘A’ to the end of that alphabet.

Here we do the combined operations of the DE and DS variations on the E-Cipher. This cipher algorithm would have the greatest security by compounding the complexity faced by the would-be cryptanalyst, yet it can still be done with just pencil and paper, although it will take more than an hour per 100 characters (perhaps two; for with more steps extra care is needed). If my life depended on it, and all I could use was pencil and paper or a text terminal, this is the cipher algorithm I would use, being extra careful and double checking my work. Don’t forget that long peculiar keys are needed to thwart a brute force attack.

| E-Cipher Overview | The E-Cipher | Beyond E-Cipher |

Examples:

'Double Substitution'

Starting with the a-z and current substitution alphabet lined up as usual,

additionally line up the prekey Alphabet at the same position relative to the a-z.

Now to encode plaintext to cipher text, do two substitution operations

a-z -> PreKey Alphabet and then a-z -> current Substitution Alphabet.

This should be easy enough and not too error prone.

Pre-Key: sparklet -> XEJKQLABWPURCTMNIVGDOFYZSH

Key: bluesauce -> SJRQCTLBEFUOVXKYZNHWGAMPID

+---------------------------------------------------------+

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| Double Substitution encrypting "hello": |

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