alt Hacker News> encryption is not ever to be considered impossible to break
One-time pads [0] are actually impossible to break, but they're pretty tricky to use: you must never ever reuse them, they must be truely random, and you need some way to share them between both parties (which isn't that easy since they need to be at least as large as all the data that you ever want to transmit).
not trying to be obtuse, but there is at least one solution, the one used to decrypt.
if you know something about the content e.g. it is for russians, or americans.
you can use a frequency analysis to identify vowels. that goes for a simple substitution cypher that is relying on low frequency of usage[one time use] and does not keep it brief.
when you further substitute numbers for words, you gain more room for verbosity.
if you have high stakes, your message in the clear, should only be useful for a limited time, at the point that it is no longer actionable.
im very familiar with one time pads random, and keyed.
they are a little simple, you can use a triaxial scheme, or a tensor like scheme, for more leg room and more complexity.
depending on what you are doing it may be necessary, to not carry any pads, but to have access at some point, to agreed upon keys, in order to generate a pad on the spot. or even work in your head, if you have skill. e.g. jackdwlovemybigsphnxfqurtz as a weak example.