Hashing both numbers (123) and (167) gives the same hashed id

[hazem-taha]

Hello

I'm generating hashed ids using the below:-

(new \Hashids\Hashids('App\Booking' . 's1lt', 10))->encode(SOME_NUMBER)

and i found that it generated two identical hashed ids although the numbers are different (123 and 167)

so both
(new \Hashids\Hashids('App\Booking' . 's1lt', 10))->encode(123)
and
(new \Hashids\Hashids('App\Booking' . 's1lt', 10))->encode(167)

gives the hash Dkq1ZKnyWa

Why is this happening ?
Thanks in advance.

[vinkla]

If you think you've found a bug. Please provide a failing test case in the HashidsTest test class in a pull request.

[j8n]

Something similar happened to me!

Error reproduction
$hash = (new Hashids\Hashids('App\Models\Model'.'_string', 16))->encode(545) --> "KQAd7lo8XLogXG69"
$hash = (new Hashids\Hashids('App\Models\Model'.'_string', 16))->encode(501) --> "KQAd7lo8JLWgXG69"

[vinkla]

@j8n as you can see, these are not the same hashes:

KQAd7lo8XLogXG69
KQAd7lo8JLWgXG69

[j8n]

Yes ok, I cannot reproduce the error again (with test data). I had a "Integrity constraint violation: 1062 Duplicate entry" for a hash id in a record

[j8n]

Ok, just to share the original as in my production env:

$hash = (new Hashids\Hashids('App\Models\Subscription'.'_OUTGO', 16))->encode(501); --> "P17zevgVkZExk80a"
$hash = (new Hashids\Hashids('App\Models\Subscription'.'_OUTGO', 16))->encode(545); --> "P17zevgVKZExk80a"
The only change is the case of the "K"

That's how I got the error above

[vinkla]

The only change is the case of the "K"

This is the expected behaviour.

[j8n]

What's the use of Hashids lib, if we get a "Integrity constraint violation" error in the database? The database seems to understand the case incorrectly.
What do I have to do?

[vinkla]

We don't recommend to store the hashids in the database. Instead encode/decode them on the fly.

Use it when you don't want to expose your database numeric ids to users.

[j8n]

ok thanks

[peterchaula]

So the hashes are unique, and the behaviour is correct, the only issue is with your database being case insensitive.

[hazem-taha]

I'm saving the hashids to the DB and it is not possible to refactor the system, is there a way to make the DB queries in laravel to be case sensitive ?

[eugene-borovov]

Setting up a collation in the database may help you.
https://dev.mysql.com/doc/refman/8.0/en/case-sensitivity.html
https://stackoverflow.com/a/6448861