That probably won't work: you need the combination of the algorithm + the key to get your data out. Of the 4 possible combinations, only 2 will yield valid dat

That probably won't work: you need the combination of the algorithm + the key to get your data out. Of the 4 possible combinations, only 2 will yield valid data. If you give a password, the cops will know what algorithm they must use (2 trials at most). Even if they don't know before hand which algorithm points to the real data, they can notice that it doesn't use all data. With your method, you can at best cast doubt: is the data not extracted real data encrypted differently (algorithm or key), or random data that the software insert by default to give everyone plausible deniability?