To find a pure digital encryption algorithm

The requirements are as follows, with a 10-bit user ID
$user _id = 5986845949;
and a pure number of encrypted salts
$salt = 102744; Variable

An additional 10-bit pure digital key is obtained by encryption (the emphasis is on the number of bits that cannot be changed), and the encryption results are discrete enough with $salt and can be reversed

To help the master, thank you very much

Reply content:

The requirements are as follows, with a 10-bit user ID
$user _id = 5986845949;
and a pure number of encrypted salts
$salt = 102744; Variable

An additional 10-bit pure digital key is obtained by encryption (the emphasis is on the number of bits that cannot be changed), and the encryption results are discrete enough with $salt and can be reversed

To help the master, thank you very much

$user _id = 5986845949;
$salt = 1111111111;

Encryption
The addition of bits is not a simple mathematical operation.
After calculation, it is concluded that:
$user _id = 6097956050;

Decrypt
Reduce by phase, do not abdicate
After calculation, it is concluded that:
$user _id = 5986845949;

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