When is CRC more appropriate to use than MD5/SHA1?

Question

When is it appropriate to use CRC for error detection versus more modern hashing functions such as MD5 or SHA1? Is the former easier to implement on embedded hardware?

Answer 1

For CRC information on implementation, speed and reliability see A painless guide to CRC error detection algorithms. It has everything on CRCs.

Unless somebody is going to try and modify your data maliciously and hide the change CRC is sufficient. Just use a "Good" (standard) polinomial.