Because it is fast, ubiquitous, and you can't produce a collision by accident. That means it's perfectly fine to use where no malicious behavior is possible. In

Because it is fast, ubiquitous, and you can't produce a collision by accident. That means it's perfectly fine to use where no malicious behavior is possible. In fact, it should be used in those instances due to the speed and availability on all platforms. Where security is a concern, use SHA-256 or SHA-512.