2.2.11.1.3 Deriving Key1 and Key2 from a Little-Endian, Unsigned Integer Key
Let I be the little-endian, unsigned integer.
Let I[X] be the Xth byte of I, where I is interpreted as a zero-base-index array of bytes. Note that because I is in little-endian byte order, I[0] is the least significant byte.
Key1 is a concatenation of the following values: I[0], I[1], I[2], I[3], I[0], I[1], I[2].
Key2 is a concatenation of the following values: I[3], I[0], I[1], I[2], I[3], I[0], I[1].