Advice for that kind of problem typically requires a lot more context, e.g.: * You need to do symmetric crypto between two MCUs, where only one has an RNG; * Yo

Advice for that kind of problem typically requires a lot more context, e.g.: * You need to do symmetric crypto between two MCUs, where only one has an RNG; * You need to do symmetric crypto with no RNG; * You can't rely on your MCU safely storing state / unreliable transports. Cryptography and libraries/standards are gradually building towards a world in which higher-and-higher level abstractions let inexperienced web/high-level application developers build safe systems. The same isn't really true for the lower-end of the embedded space, and consequently you can't really produce an equivalent set of (reasonable) guidelines like the ones linked.