1. A method for dynamic modification of allowable electronic message properties on a mobile device, the method comprising: generating an electronic message by receiving, via a user interface, one or more entries made in one or more various fields of the message, wherein an option from a first list of available security encoding options to apply to the message is available for selection; monitoring the one or more entries, while data is being entered in the one or more various fields via the user interface, to determine whether the one or more entries affect the first list of available security encoding options and, if so, automatically updating said first list of available security encoding options to apply to said message to generate a second list of available security encoding options, while the message is being composed; wherein the automatically updating is based on contents of the one or more entries and a system policy applicable to said contents; displaying the second list of available security encoding options to apply to the message based on the results of the monitoring and the automatically updating, while the message is being composed; wherein the second list of available security encoding options comprises a lower number of security encoding options than a number of security encoding options in the first list of available security encoding options, said lower number of security encoding options comprising a minimum encoding requirement; and receiving a selected security encoding option from the second list of available security encoding options to apply to the message, prior to sending the message.