1. A method of encoding data into a chain reaction code having systematic output symbols and non-systematic output symbols, the method comprising: generating, from the data, a set of input symbols, the input symbols comprising systematic output symbols; and generating, from the set of input symbols, one or more non-systematic output symbols, wherein each of the one or more non-systematic output symbols is selected from an alphabet of non-systematic output symbols, and wherein each non-systematic output symbol is generated as a function of one or more of the input symbols, wherein any subset of the set of input symbols is recoverable from (i) a predetermined number of non-systematic output symbols, or (ii) a combination of (a) input symbols which are not included in the subset of input symbols that are to be recovered and (b) one or more of the non-systematic output symbols.