See what encryption method this is and can it be decrypted?

The ciphertext looks like this: V53::eJwzcDJAASYWRhaGLsYGLqamTpZGji4GJuYGlpbGbm4mhhbmxi6OAPBkCik=
The plaintext corresponds to an 11-digit mobile phone number, which is certain;
So I would like to ask what encryption method is used?

Reply content:

The ciphertext looks like this: V53::eJwzcDJAASYWRhaGLsYGLqamTpZGji4GJuYGlpbGbm4mhhbmxi6OAPBkCik=
The plain text corresponds to an 11-digit mobile phone number, which is certain;
So I would like to ask what encryption method is used?

I can definitely tell you that this is encoded binary data (:: after)
It’s really hard to see what is encrypted

You definitely cannot decrypt this. Judging from the results, it should be encrypted with base64, but after several layers of encryption and the salt used in encryption, I don’t know how to decrypt it. . .

Basically it should not be decrypted. . .