Yandex decrypts MD5?

Question

Yandex

Yandex audiences offer to download hashed data instead of open data:

But the hash is irreversible. Okay phones. You can pre-compile a list of hashes of all phones and choose from it. What about the list of all email addresses? There are a lot more options out there.
How do you think this technology works inside?

Answer 1

How do you think this technology works inside?

They store the hash, they don't need open data.
If it is necessary to check the data, only their hashes will be checked.

Answer 2

Strong hash - irreversible
MD5 weak
https://en.wikipedia.org/wiki/MD5#Collision_vulner...
A strong hash can be brute force if there is a brute force range and the value is not salted

Answer 3

If you upload phones, the phones will be checked.
If you upload phone hashes, the hashed phones will be checked against the uploaded hashes.

Answer 4

The hash is irreversible, but md5 is broken and not considered reliable. Having information about the structure of the hash content, with the power of Yandex, they may well open it. A phone number is just 10**11, that is, 100 billion options, and that's if it's brutal.

Answer 5

They calculate the hash themselves and check it against your data