Cyclic Redundancy Check (CRC)
Binary Check Digit Method
Make number divisible by P=110101 (n+1=6 bits)
Example: M=1010001101 is to be sent
1. Left-shift M by n bits 2nM= 101000110100000
2. Divide 2nM by P, find remainder: R=01110
3. Subtract remainder from P ? Not required in Mod 2
4. Add the result of step 2 to step 1 : T=101000110101110
5. Check that the result T is divisible by P.