Documentation

i2osp converts a positive integer into a byte string.

The first byte is LSB (least significant byte); the last byte is the MSB (most significant byte)

os2ip converts a byte string into a positive integer.

Just like i2osp , but takes an extra parameter for size. If the number is too big to fit in len bytes, Nothing is returned otherwise the number is padded with 0 to fit the len required.

Just like i2ospOf except that it doesn't expect a failure: i.e. an integer larger than the number of output bytes requested.

For example if you just took a modulo of the number that represent the size (example the RSA modulo n).