Difference between CRC and hash method (MD5, SHA1)

问题:

Both CRC and hash methods can be used to verify the integrity of the original data. Why do most systems uses hash method nowadays?

回答1:

CRC was designed to prevent transmission errors, not malicious action.

Therefore, it isn't collision resistant.

In particular, the linear properties of CRC codes even allow an attacker to modify a message in such a way as to leave the check value unchanged

回答2:

HASH methods (ONE WAY ENCRYPTION) are more complex (and powerful) than simple check codes (CRC). Not only they could be used to verify data integrity, but they also make sure no one could infer the original message that originated the hash value.