# 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 %}


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.sign.singpass.gov.sg/for-users/verifying-sign-with-singpass-signatures.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.