Getting started¶

First of all: Add the library to your build¶

build.gradle:

dependencies {
    implementation 'net.gini.android:gini-bank-api-lib:2.0.2'
}

Integrating the Gini Bank API Library¶

The Gini Bank API Library provides the GiniBankAPI class which is a façade to all functionality of the library. We recommend using a single instance of this class and avoid instantiating it each time you need to interact with the Gini Bank API. You can reuse the instance either through your Application subclass or via a dependency injection solution. This has the benefits that the library can reuse sessions between requests to the Gini Bank API which may save a noteworthy number of HTTP requests.

Creating the GiniBankAPI instance¶

In order to create an instance of the GiniBankAPI class, you need both your client id and your client secret. If you don’t have a client id and client secret yet, you need to contact us and we’ll provide you with the credentials.

All requests to the Gini Bank API are made on behalf of a user. This means particularly that all created documents are bound to a specific user account. But since you are most likely only interested in the results of the semantic document analysis and not in a cloud document storage system, the Gini Bank API has the feature of anonymous users. This means that user accounts are created on the fly and the user account is unknown to your application’s user.

The following example describes how to use the Gini Bank API in your application with such anonymous user accounts. To use the Gini Bank API, you must create an instance of the GiniBankAPI class. The GiniBankAPI instance is configured and created with the help of the GiniBankAPIBuilder class. In this example, the anonymous users are created with the email domain “example.com”. An example of a username created with this configuration would be 550e8400-e29b-11d4-a716-446655440000@example.com

// The GiniBankAPI instance is a facade to all available managers of the library. Configure and
// create the library with the GiniBankAPIBuilder.
val giniBankApi: GiniBankAPI =
        GiniBankAPIBuilder(context, "gini-client-id", "GiniClientSecret", "example.com")
                .build();

// The BankApiDocumentManager provides the high-level API to work with documents.
val documentManager: BankApiDocumentManager = giniBankApi.documentManager;

Public Key Pinning¶

Public key pinning is provided using the Android Network Security Configuration and TrustKit.

To use public key pinning you can either create an Android network security configuration xml file or set a custom TrustManager implementation.

The network security configuration is supported natively on Android Nougat (API Level 24) and newer. For versions between API Level 21 and 23 the Gini SDK relies on TrustKit.

The custom TrustManager is supported on all Android versions.

We recommend reading the Android Network Security Configuration guide and the TrustKit limitations for API Levels 21 to 23.

Configure Pinning¶

The following sample configuration shows how to set the public key pin for the two domains. The Gini Bank API Library uses by default pay-api.gini.net and user.gini.net. It should be saved under res/xml/network_security_config.xml:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <domain-config>
        <trustkit-config
            disableDefaultReportUri="true"
            enforcePinning="true" />
        <domain includeSubdomains="false">pay-api.gini.net</domain>
        <pin-set>
            <!-- old *.gini.net public key-->
            <pin digest="SHA-256">cNzbGowA+LNeQ681yMm8ulHxXiGojHE8qAjI+M7bIxU=</pin>
            <!-- new *.gini.net public key, active from around June 2020 -->
            <pin digest="SHA-256">zEVdOCzXU8euGVuMJYPr3DUU/d1CaKevtr0dW0XzZNo=</pin>
        </pin-set>
        <domain-config>
            <trustkit-config
                disableDefaultReportUri="true"
                enforcePinning="true" />
            <domain includeSubdomains="false">user.gini.net</domain>
        </domain-config>
    </domain-config>
</network-security-config>

Note

If you set different base urls when instantiating with the GiniBankAPIBuilder, then make sure you set matching domains in the network security configuration xml.

Warning

The above digests serve as an example only. You should always create the digest yourself from the Gini API’s public key and use that one (see `Extract Hash From gini.net`_). If you received a digest from us then always validate it by comparing it to the digest you created from the public key (see Extract Hash From Public Key). Failing to validate a digest may lead to security vulnerabilities.

TrustKit¶

The TrustKit configuration tag <trustkit-config> is required in order to disable TrustKit reporting and to enforce public key pinning. This is important because without it TrustKit won’t throw CertificateExceptions if the local public keys didn’t match any of the remote ones, effectively disabling pinning. The only downside of enforcing pinning is that two public key hashes are required. In the example above we create and used a “zero” key hash as a placeholder. Setting the same key hash twice won’t help since key hashes are stored in a set. Ideally you should use a backup public key hash as the second one.

In your AndroidManifest.xml you need to set the android:networkSecurityConfig attribute on the <application> tag to point to the xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest ...>
    ...
    <application android:networkSecurityConfig="@xml/network_security_config">
    ...
</manifest>

Enable Pinning with a Network Security Configuration¶

For the library to know about the xml you need to set the xml resource id using the GiniBankAPIBuilder#setNetworkSecurityConfigResId() method:

val giniBankApi: GiniBankAPI = GiniBankAPIBuilder(context, "gini-client-id", "GiniClientSecret", "example.com")
        .setNetworkSecurityConfigResId(R.xml.network_security_config)
        .build();

Enable Pinning with a custom TrustManager implementation¶

You can also take full control over which certificates to trust by passing your own TrustManager implementation to the GiniBankAPIBuilder#setTrustManager() method:

val giniBankApi: GiniBankAPI = GiniBankAPIBuilder(context, "gini-client-id", "GiniClientSecret", "example.com")
        .setTrustManager(yourTrustManager)
        .build();

Warning

Setting a custom TrustManager will override the network security configuration.

Extract Hash From pay-api.gini.net¶

The current Gini Bank API public key SHA256 hash digest in Base64 encoding can be extracted with the following openssl commands:

$ openssl s_client -servername pay-api.gini.net -connect pay-api.gini.net:443 | openssl x509 -pubkey -noout | openssl pkey -pubin -outform der | openssl dgst -sha256 -binary | openssl enc -base64

Extract Hash From Public Key¶

You can also extract the hash from a public key. The following example shows how to extract it from a public key named pay-api.gini.pub:

$ cat pay-api.gini.pub | openssl pkey -pubin -outform der | openssl dgst -sha256 -binary | openssl enc -base64