In this case, $fingerprint is the fingerprint of the public key whose private key shall be able to decrypt the text. The private key that you want to encrypt the text with has to be loaded via gnupg_addsignkey().
In this case, $fingerprint is the fingerprint of the public key whose private key shall be able to decrypt the text. The private key that you want to encrypt the text with has to be loaded via gnupg_addsignkey().