> For the complete documentation index, see [llms.txt](https://docs.sign.singpass.gov.sg/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sign.singpass.gov.sg/for-users/verifying-sign-with-singpass-signatures.md).

# Verifying Sign with Singpass Signatures

Sign with Singpass signatures can be verified using PDF reader software, such as **Adobe Acrobat Reader** application ([download here](https://get.adobe.com/uk/reader/)).

{% hint style="warning" %}
Please ensure that the document has not been modified since your signature has been created, as this will invalidate the signature.
{% endhint %}

## Verifying signatures with Adobe Acrobat Reader <a href="#verifying-signatures" id="verifying-signatures"></a>

Please follow the steps below to verify a Sign with Singpass signature.

{% stepper %}
{% step %}

#### **Open up signed document on Adobe Acrobat Reader**

{% endstep %}

{% step %}

#### **Check if green tick with "Signed and all signatures are valid"**

{% hint style="warning" %}
If you see "Certificate validity is unknown", this is because you do not have the Singpass root signing certificate on your device. Please refer to this [guide](/for-users/verifying-sign-with-singpass-signatures/loading-singpass-root-signing-certificate.md) to install the Singpass root signing certificate.
{% endhint %}

<figure><img src="/files/YbJqqsuOy3HhYB5BY5v9" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

#### Go to signature panel

<figure><img src="/files/IVxWZ5ZW3Pe9tGpgWfkF" alt=""><figcaption></figcaption></figure>

In signature panel, each signature should show:

* Document has not been modified
* Signer's identity is valid
* The signature includes an embedded timestamp
* Signature is long term validation (LTV) enabled

<figure><img src="/files/nbS1NNWOKBWGL7q8ZmfN" alt=""><figcaption></figcaption></figure>

Document owner should "click to view this version" to visually inspect that the contents of the document version is signed correctly.

<figure><img src="/files/aXyMOgg1dekGSJV1OJzi" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

#### Right-click on each signature and select "Show Signature Properties".

<figure><img src="/files/RpwmjOZ3vIPCdCpF6t0C" alt=""><figcaption></figcaption></figure>

The following modal should appear, and it will tell you:

* The name of the signer (e.g. "MICHAEL ONG")
* The time the document was signed

<figure><img src="/files/ZRBtlJq3B9XlJZL3srVR" alt="" width="563"><figcaption></figcaption></figure>

If you select "Show Signer's Certificate" at the bottom, you will see another modal with details about the certificate. Ensure that the the following details are correct:&#x20;

* Singapore National Root CA - B1
* Singapore NDI Intermediate CA 1 - B2
* Signer's full name (as per NRIC)

<figure><img src="/files/ScfEka3lCrQtsCiCaEHA" alt=""><figcaption></figcaption></figure>

Click the full name and then "details".&#x20;

Check under "Subject" that signer's name and last 4 characters of NRIC is correct.

<figure><img src="/files/zh1GEjnavNEKDYVTfj6x" alt=""><figcaption></figcaption></figure>

<br>

<br>
{% endstep %}
{% endstepper %}