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PHP package for SPID authentication.

This PHP package is aimed at implementing SPID Service Providers. SPID is the Italian digital identity system, which enables citizens to access all public services with a single set of credentials. This package provides a layer of abstraction over the SAML protocol by exposing just the subset required in order to implement SPID authentication in a web application.

Alternatives for PHP:

Framework specific libraries and examples based on spid-php-lib:

Alternatives for other languages:

Table of Contents

Repository layout

  • bin/ auxiliary scripts
  • example/ contains a demo application
  • src/ contains the library implementation
  • test/ contains the unit tests

Getting Started

Tested on: amd64 Debian 9.5 (stretch, current stable) with PHP 7.0.

Supports PHP 7.0, 7.1 and 7.2.


sudo apt install composer make openssl php-curl php-zip php-xml

Configuring and Installing

NOTE: during testing, please use the test Identity Provider spid-testenv2.

  1. Install with composer

    composer require italia/spid-php-lib

  2. (OPTIONAL) Manually generate key and certificate files for your Service Provider (SP).

    Example: openssl req -x509 -nodes -sha256 -days 365 -newkey rsa:2048 -subj "/C=IT/ST=Italy/L=Milan/O=myservice/CN=localhost" -keyout sp.key -out sp.crt

    This step can be skipped: the library takes care of this step automatically if you declare the optional sp_key_cert_values key in the settings array. Check the example in the Usage section for further details.

  3. Download the Identity Provider (IdP) metadata files and place them in a directory in your project, for example idp_metadata. A convenience tool is provided to download those of the production IdPs: vendor/italia/spid-php-lib/bin/download_idp_metadata.php, example usage:

    mkdir idp_metadata
    php vendor/italia/spid-php-lib/bin/download_idp_metadata.php ./idp_metadata

    TEST ENVIRONMENT: If you are using spid-testenv2, manually download the IdP metadata and place it in your idp_metadata folder

  4. Make your SP known to IdPs: for production follow the guidelines at

    TEST ENVIRONMENT: simply download your Service Provider (SP) metadata and place it in the appropriate folder of the test environment. The test environment must be restarted after every change to the SP metadata.


All classes provided by this package reside in the Italia\Spid namespace. More detailed documentation is available in the SAMLInterface.php file.

Load them using the composer-generated autoloader:

require_once(__DIR__ . "/vendor/autoload.php");

The main class is Italia\Spid\Sp (service provider).

Generate a settings array following this guideline

$settings = array(
    'sp_entityid' => SP_BASE_URL, // preferred: https protocol, no trailing slash, example:
    'sp_key_file' => '/path/to/sp.key',
    'sp_cert_file' => '/path/to/sp.crt',
    'sp_comparison' => 'exact', // one of: "exact", "minimum", "better" or "maximum"
    'sp_assertionconsumerservice' => [
        // order is important ! the 0-base index in this array will be used as ID in the calls
        SP_BASE_URL . '/acs',
    'sp_singlelogoutservice' => [
        // order is important ! the 0-base index in this array will be used as ID in the calls
        [SP_BASE_URL . '/slo', 'POST'],
        [SP_BASE_URL . '/slo', 'REDIRECT']
    'sp_org_name' => 'your organization full name',
    'sp_org_display_name' => 'your organization display name',
    'sp_key_cert_values' => [ // Optional: remove this if you want to generate .key & .crt files manually
        'countryName' => 'Your Country',
        'stateOrProvinceName' => 'Your Province or State',
        'localityName' => 'Locality',
        'commonName' => 'Name',
        'emailAddress' => '',
    'idp_metadata_folder' => '/path/to/idp_metadata/',
    'sp_attributeconsumingservice' => [
        // order is important ! the 0-base index in this array will be used as ID in the calls
        ["name", "familyName", "fiscalNumber", "email", "spidCode"],
    // Time in seconds of skew that is acceptable between client and server when checking OnBefore and NotOnOrAfter
    // assertion condition validity timestamps, and IssueInstant response / assertion timestamps. Optional.
    // Default is 0. Acceptable range: 0-300 (inclusive)
    'accepted_clock_skew_seconds' => 100

then initialize the main Sp class

$sp = new Italia\Spid\Sp($settings);

Don't want the library to generate .key and .crt files for you? Then remove the sp_key_cert_values key from the settings array, or decalre

// $autoconfiguration skips .key/.crt generation if set to false
$sp = new Italia\Spid\Sp($settings, null, $autoconfiguration = false);

Performing login

// shortname of IdP, same as the name of corresponding IdP metadata file, without .xml
$idpName = 'testenv';
// index of assertion consumer service as per the SP metadata (sp_assertionconsumerservice in settings array)
$assertId = 0;
// index of attribute consuming service as per the SP metadata (sp_attributeconsumingservice in settings array)
$attrId = 1;

// Generate the login URL and redirect to the IdP login page
$sp->login($idpName, $assertId, $attrId);

Complete the login operation by calling


at the assertion consumer service URL.

Then call

$userAttributes = $sp->getAttributes();

to receive an array of the requested user attributes.

Performing logout


// index of single logout service as per the SP metadata (sp_singlelogoutservice in settings array)
$sloId = 0;


The method will redirect to the IdP Single Logout page, or return false if you are not logged in.

Complete API

Method Description
__contruct($settings, $protocol = null, $autoconfigure = true) $settings should be based on the example provided in the Usage section. $protocol represents the protocol used for login. At the moment only SAML is supported, and can be selected by either $protocol = 'saml' or the default $protocol = null. $autoconfigure tells the constructor if it should check for .key and .crt files at the specified location from the $settings array and generate them in case they are not found. Set this to false if you wish to generate those manually.
loadIdpFromFile(string $filename) loads an Idp object by parsing the provided XML at $filename
getIdpList() : array loads all the Idp objects from the idp_metadata_folder provided in settings
getIdp(string $filename) alias of loadIdpFromFile
getSPMetadata() : string returns the SP metadata as a string
login(string $idpFilename, int $assertID, int $attrID, $level = 1, string $redirectTo = null, $shouldRedirect = true) login with REDIRECT binding. Use $idpFilename to select in IdP for login by indicating the name (without extension) of an XML file in your idp_metadata_folder. $assertID and $attrID indicate respectively the array index of sp_assertionconsumerservice and sp_attributeconsumingservice provided in settings. Optional parameters: $level for SPID authentication level (1, 2 or 3), $redirectTo to indicate an url to redirect to after login, $shouldRedirect to indicate if the login function should automatically redirect to the IdP or should return the login url as a string
loginPost(string $idpName, int $ass, int $attr, $level = 1, string $redirectTo = null, $shouldRedirect = true) like login, but uses POST binding
logout(int $slo, string $redirectTo = null, $shouldRedirect = true) logout with REDIRECT binding. $slo indicates the array index of the sp_singlelogoutservice provided in settings. Optional parameters: $redirectTo to indicate an url to redirect to after login, $shouldRedirect to indicate if the login function should automatically redirect to the IdP or should return the login url as a string
logoutPost(int $slo, string $redirectTo = null, $shouldRedirect = true) like logout, but uses POST binding
isAuthenticated() : bool checks if the user is authenticated. This method MUST be called after login and logout to finalize the operation.
getAttributes() : array If you requested attributes with an attribute consuming service during login, this method will return them in array format


A basic demo application is provided in the example/ directory of this repository.

/example and /tests folders are NOT provided with the production version from packagist, remember to require the dev-develop version or just clone this repository (advised)

To try it out:

  1. Generate a test certificate and key pair with:

    openssl req -x509 -nodes -sha256 -days 365 -newkey rsa:2048 -subj "/C=IT/ST=Italy/L=Milan/O=myservice/CN=localhost" -keyout sp.key -out sp.crt
  2. Adapt the hostname of the SP changing the $base variable in the example/index.php file; the browser you'll be testing from must be able to resolve the FQDN (the default is Using HTTPS is strongly suggested.

  3. Configure and install the test IdP spid-testenv2

  4. Serve the example dir from your preferred webserver

  5. Visit to get the SP metadata, then copy these over to the IdP and register the SP with the IdP

  6. Visit to get the IdP metadata, then save it as example/idp_metadata/testenv.xml to register the IdP with the SP

  7. Visit: and click login.

Demo application

A Docker-based demo application is available at


  • provides a lean implementation without relying on external SAML packages
  • routing-agnostic, can be integrated in any web framework / CMS
  • uses a session to store the authentication result and the received attributes
  • does not currently support Attribute Authority (AA)

Compliance with SPID regulations (for Service Providers)
parsing of IdP XML metadata (
support for multiple signing certificates in IdP XML metadata (
parsing of AA XML metadata (2.2.4)
SP XML metadata generation (1.3.2)
AuthnRequest generation (
generation of AuthnRequest XML
HTTP-Redirect binding
HTTP-POST binding
AssertionConsumerServiceURL customization The library uses AssertionConsumerServiceIndex customization which is preferred
AssertionConsumerServiceIndex customization
AttributeConsumingServiceIndex customization
AuthnContextClassRef (SPID level) customization
RequestedAuthnContext/@Comparison customization
RelayState customization (1.2.2)
Response/Assertion parsing
verification of Signature value (if any)
verification of Signature certificate (if any) against IdP/AA metadata
verification of Assertion/Signature value
verification of Assertion/Signature certificate against IdP/AA metadata
verification of SubjectConfirmationData/@Recipient
verification of SubjectConfirmationData/@NotOnOrAfter
verification of SubjectConfirmationData/@InResponseTo
verification of Issuer
verification of Assertion/Issuer
verification of Destination
verification of Conditions/@NotBefore
verification of Conditions/@NotOnOrAfter
verification of Audience
parsing of Response with no Assertion (authentication/query failure)
parsing of failure StatusCode (Requester/Responder)
Response/Assertion parsing for SSO (1.2.1,, 1.3.1):
parsing of NameID
parsing of AuthnContextClassRef (SPID level)
parsing of attributes
Response/Assertion parsing for attribute query (, 2.3.1):
parsing of attributes
LogoutRequest generation (for SP-initiated logout):
generation of LogoutRequest XML
HTTP-Redirect binding
HTTP-POST binding
LogoutResponse parsing (for SP-initiated logout):
parsing of LogoutResponse XML
verification of Response/Signature value (if any)
verification of Response/Signature certificate (if any) against IdP metadata
verification of Issuer
verification of Destination
PartialLogout detection pending, see: #46
LogoutRequest parsing (for third-party-initiated logout):
parsing of LogoutRequest XML
verification of Response/Signature value (if any)
verification of Response/Signature certificate (if any) against IdP metadata
verification of Issuer
verification of Destination
parsing of NameID
LogoutResponse generation (for third-party-initiated logout):
generation of LogoutResponse XML
HTTP-Redirect binding
HTTP-POST binding
PartialLogout customization pending, see: #46
AttributeQuery generation (
generation of AttributeQuery XML
SOAP binding (client)

More features

  • Generation of SPID button markup


It is advised to install a browser plugin to trace SAML messages:

In addition, you can use the SAML Developer Tools provided by onelogin to understand what is going on


To test and lint this package you must place yourself in its root directory, then follow the provided instructions.

Assuming you followed the installation instructions with composer, simply do:

cd vendor/italia/spid-php-lib

Unit tests

Install prerequisites with composer, generate key and certificate for the SP and download the metadata for all current production IdPs with:

composer install
bin/download_idp_metadata.php example/idp_metadata

then launch the unit tests with PHPunit:

./vendor/bin/phpunit --stderr --testdox tests


This project complies with the PSR-2: Coding Style Guide.

Make sure you are in the package directory, then lint the code with:

./vendor/bin/phpcs --standard=PSR2 xxx.php


For your contributions please use the git-flow workflow.

See also


Lorenzo Cattaneo and Paolo Greppi, simevo s.r.l.


Copyright (c) 2018-2020, Developers Italia

License: BSD 3-Clause, see LICENSE file.