Benjamin's Code System
During the mid-to-late 1930s Walter Benjamin and Gershom Sholom, the latter still living in Germany, developed a code system which enabled them to communicate by mail while concealing their message from the police. This code operates as follows: 
A base message is written. This message may be any number of words long. A number n is produced which contains the same number of digits as there are words in the message. Each word is therewith paired with a digit n[x] >= 0.
To encode the message, a new intelligible message is produced in the cracks of the previous message. Thus, for each word place n[x] new words before each word, keeping in mind that the new message must make sense. 

Benjamin and Sholom did not specify the placement of punctuation, therefore, punctuation is at the discretion of the encoder. Neither did they propose how the code number was to be produced; therefore, it must also be left to the encoder to produce such an operation. It is conceivable that this operation may be nested any number of times to expand a single sentence into an entire text and conceal multiple messages within a single, larger corpus.

And example:

BASE: To be or not to be that is the question.

[Number must be 10 digits long.]
1463114631 

[this number is constructed by the author for the sake of this demonstration and has no hidden mechanism]
So, 
To[1] be[4] or[6] not[3] to[1] be[1] that[4] is[6] the[3] question[1]

Ship to shore communications could not be made today. Forget not to be whatever is needed, so that you may definitely arrive on time. Is there anyone with the last question?