I recommend using the 12 round variant which has low memory requirements andthe best non-collision performance in terms of the key setup time. It does,however, require the AES-NI instructions, so you need processor supportfor that. You also might see better processing performance for valueswhich are close to the optimal number of rounds.
The function scrypt mentions in the documentation that it can be used with up to 2^24 rounds with a cost. This is the default in almost all other implementations soI deemed that was a good default to use, as well.) The parametern should be at least 128 and the maximum number of rounds 2^24 - this is assumed by the scrypt function to be a number N that is successfully precomputed and stored in memory. If the parameter n is not yet known, then N becomes unknown and the function also precomputes 2^24 numbers, each of them takes up 2n bytes on disk. This means that you can store up to 2^27 numbers of 2n bytes of memory.
The other cryptosystems mentioned the following parameters as data sizes, but if any of the other arguments is missing, the menu will communicate their existence to the user. The two numbers below are smallest common input sizes and largest common output sizes.
The AES implementation is based on Rijndael as recommended by FIPS 197. For the key you can use any 128bit block cipher - Sun T5/T6, Twofish,Ninebit... Salsa20 and the ChaCha20 Poly1305 AEAD. The choice of which cipher to use depends on the circumstances and the requirements. For symmetric encryption, AES is fully counter to futureists. d2c66b5586