Here is what i have or as far as i know about GPG
1. when GPG encrypt using a public key , we need to specify a keyid/user\_id to identity that key.

1. but when decrypt, looks like we do not need to specify the keyid/user\_id.

So my question is :
How GPG identify or find out the corresponding private key of that encryption public key ?
Is that information indicated in the encrypted file ?