Studying Hare's implementation of SipHash the initializers XOR's its operand into its properties with some magic numbers.

Its write method uses a buffer to split its input into 8byte chunks (taking into account a configurable prefix). For each chunk it performs a quad add-rotate-XOR operation upon 4 64bit numbers a configurable number of times, XORing in the written bytes both before & after.

To finish the hash it pads the buffer with 0 & performs another several rounds of that.

1/1Fin today!