CODEWITHSUNDEEP
phpcrc32
Adam Baranyai
Adam Baranyai

Reputation: 3867

Is CRC32 suitable for this operation?

If I want to generate a checksum, for some product attributes concatanated with a custom string, and use this checksum later on, to see if any attribute in the same product changed over time, is php's crc32 method suitable?

For example, let's say I have a product with the following attributes:

color: red
size: xl

I am trying to get the checksum for this product by creating the following string: red||xl and then running the crc32 function on this string. If later on, the size is identified differently, or the product gets a new attribute, I want to identify this difference by the changing of the checksum on this product.

The baseline is, am I safe in using the crc32 method for this, or I should opt for a slower but more secure hashing algorithm, with less collission?

Upvotes: 0

Views: 118

Answers (1)

Mark Adler
Mark Adler

Reputation: 112432

Define "suitable".

I see little reason to not use a cryptographic hash here. If you have a) millions of strings, or b) malicious users who would like to trick you into thinking the attributes are the same, you should use a cryptographic hash. SHA-256 should be readily available. Feel free to use only 128 bits of it if you need to save the space. You'll still have a negligible probability of collision.

Update:

Based on the comments, a cryptographic hash would not be of benefit. I would recommend XXH128 as an extremely fast hash that would effectively eliminate the possibility of collision.

Upvotes: 1

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