Fix compiling with only decode/encode support

[cryptoAlgorithm]

Although support is provided for compiling with only encode/decode support thru the USE_ENCODE_FUNCTIONS and USE_DECODE_FUNCTIONS definitions respectively, some portions of the code are not properly wrapped with #ifdef conditions. This causes errors when only one of USE_ENCODE_FUNCTIONS or USE_DECODE_FUNCTIONS is defined as those functions rely on other functions that are correctly wrapped (and hence removed).