# 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.
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## 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 %}
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#### **Open up signed document on Adobe Acrobat Reader**

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{% 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](https://docs.sign.singpass.gov.sg/for-users/verifying-sign-with-singpass-signatures/loading-singpass-root-signing-certificate) to install the Singpass root signing certificate.
{% endhint %}

<figure><img src="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2Fs8x7K0Su5JhDBaDHbaBH%2FFrame%20427319133.png?alt=media&#x26;token=1317dc66-2a53-4d8d-a529-c39de5a45de4" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

#### Go to signature panel

<figure><img src="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2FZTtpMW3xZF3P1j5sACTO%2FFrame%20427319137.png?alt=media&#x26;token=d06a5e3f-af94-41b3-ae65-89df83a18cff" 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="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2FTCP2t9Jq34Eor9AbfH8w%2FFrame%20427319134.png?alt=media&#x26;token=a60f8cd8-b1dd-45b6-a80e-4a6a6e72e4cf" 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="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2FHjFQBIyQgXqO0druQHgf%2FFrame%20427319140.png?alt=media&#x26;token=32385a27-eac0-4f9b-9148-355abb76cefb" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

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

<figure><img src="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2Fgiw4apVWbBMjTiBUZikP%2FFrame%20427319135.png?alt=media&#x26;token=06941f52-b6fd-40e7-b2e8-fdb104a0bb6d" 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="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2FAIzDvJufSYscc3gDYbWF%2FShow%20Signer&#x27;s%20Certificate.png?alt=media&#x26;token=d750fa28-51e5-48bb-ad1c-9e13aa2b3b34" 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="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2FHcbIwSTXxUXQBL7EbIY9%2FFrame%20427319138.png?alt=media&#x26;token=49cb53db-2cd5-499c-a869-06f0ed13d635" 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="https://372330916-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FXnljQgt54HuOtH3cKCRP%2Fuploads%2FA5i8pFzxEzEVRDlCZvS7%2FFrame%20427319139.png?alt=media&#x26;token=f6ccb1f1-29d1-4c93-a25e-7fe81e988f9e" alt=""><figcaption></figcaption></figure>

<br>

<br>
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{% endstepper %}