##THESE RECORDS ARE TO BE DESTROYED UPON COMPLETION OF THE RENEWED SECURITY MEASURES. IF THESE RECORDS ARE FOUND FOR WHATEVER REASON, THE READER IS CHARGED TO DESTROY THEM IMMEDIATELY. ##

[the following text is the decoded version of the records]

It is of utmost importance that new security measures be set in place if the resistance is to survive.

Those of my ill fated predecessor were much too weak, and this fact ultimately led to his demise. However, it is not proper to speak ill of the dead, and in his favour he did have one fallback in place; the emergency protocol.

It is a deceptively simple cipher substitution method, primarily to buy time in which to construct countermeasures and to limit the damage of a breach.


Concerning secrecy of great importance, there are a number of factors to consider and strategies at the disposal of the skilled cryptographer.

The primary task is to be able to communicate information clearly and concisely with as little mechanical and mental labour as possible in encoding and decoding. A balance must be struck with complexity, to make a calcualted or a brute force attempt of an unwelcome outsider sufficiently diffcult, or ideally impossible.
But this is only the pre-requisite of an effective codec, and by itself it is next to useless as a security measure.

[end of part 1]

To trust a strong code to protect your secrets is like depending on a great wall to protect a city. While it may initially block all attacks and be tremendously large and intimidating, the wall will surely not be uniformly strong - there will be points that are weaker, and these will be where it is attacked.
And consider the scenario where somehow the wall is breached - what then? Without further measures of defence, at the point the wall is broken, the city is utterly lost.
And think, that in the security world, it is not immediately known wether the wall is breached or not until it is much too late. Truly then, to keep information safe is much like playing a board game in which you, as the player, are neither permitted to see the board nor the pieces and their positions.

What then, can one do, against such relentless and essentially invisible foes?

Firstly it is necesary to compartmentalise information. In an ideal system, all agents are fully trustworthy and impervious to deception and torture, but of course this is never the case. There must therefore be a system in which all information is shared on an absolute "need to know" basis, in a strong heirarchy. It may even be necesary at times to feed false information to allies.
Cases in which this practice are most useful are when the agent in question is known to be under surveillance by the enemy, is suspected to be untrustworthy, or is likely to be captured.
Infact, much energy must be spent spying on those closest to the resistance, particularly in cases of questionable motive.

[end of part 2. Next: effective deployment of codes ]

Broadly speaking, there are two types of secret message - steganographic and cryptographic.

The former entials a method of hiding a message in plain sight, or by some special means that does not necessarily require encryption, while the latter is the classic computational cipher method. There are pros and cons to each method, as with all things, and the importance of knowing which to use in a given situation is not to be underestimated.

A steganographic message carries the advantage that it is publicly deployable. A practical application of this would be to post a personals advert in a newspaper. If the terms applied have a pre-determined meaning known to all concerned, in a day, a brief but important message could in theory be broadcast to every party member with access to the Kingsway Post. There are many other useful steganographical methods, all sharing the advantage that they are not outwardly suspicious and may be safely used in plain sight by any agent.

Cryptographic messages possess qualities of a different nature. They can pass confidently through dubious channels, provided the correct precautions are taken. It is inadvisable, for example, for a party member to be seen posting a letter full of ciphertext - even if the meaning is not discerned, they have already provided more than enough grounds for the seventen to interrogate them. A safer method would be to place agents or acquire agents from within the postal service and through this connection filter messages without return addresses.

If, on its travels, a message is intercepted, the encrypted form of the message (or cipher text) should prove incomprehensible to the interceptor. Assuming the interceptor allows a message to pass, and settles merely to make a copy, hoping to interpret the meaning of it in secret, the strength of the code is then directly put to the test.

[Next: effective deployment of codes continued ]