<?php$data="Your secret data goes here...";$encrypted_data = "";//Sample Public Key in your pem file:$publicKey='-----BEGIN PUBLIC KEY-----MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAoKQH6XtTUYPSIWPjtcA3I6VBF3F3TZMd9RImq0YG55qGIJvOOP0MeVibD7MFtN4hv6ke3NyYaaUfRaxQ6mrDGzdYOzdkqebjUzSNnwd8eQCRL2rvOsgUhf2yghLBlxq+9yfpzDV3KQ58JkCqvV1trBt/ISjPtgbK24V3v55z+cN558DMgyQmV8pYrTFzktFVlJP20DR08HzIGimlWq/ixUfY4KrznqapnKMw1u6SVVgGem67LC8HO9Mfx3KDseJaG7oUbSWq8vaTW2ewjEfs5JRt1OMUol7CHHtqVprcMizclqCO9KhDmpussq19l0LbKbGkC73uK0Nm8RyfGhiWCQIDAQAB-----END PUBLIC KEY-----';//following line will return the object of OpenSSLAsymmetricKey$oOpenSSLAsymmetricKey = openssl_get_publickey($publicKey);//following line will return the encrypted data with RSA 2048 encryption$encryptedData = openssl_public_encrypt( $data, $encrypted_data, $oOpenSSLAsymmetricKey, OPENSSL_SSLV23_PADDING);var_dump($encrypted_data);