Inputs			Outputs
X	Y	Z	Q
0	X	0	0
0	X	1	1
1	0	X	0
1	1	X	1

Choose function (or Ch Function) is a Boolean function that represents a 2:1 MUX. The choose function is frequently found in various cryptographic hash functions.

Which can be implemented as:

See also

• rotate left (ROL)
• rotate right (ROR)
• parity function (PAR)
• majority function (MAJ)