Students & ApplicantsPrivacy

Scanned ID for a rental or job application: what to blur, what to keep, and how to send it

2026-09-19 · 3 min read

Providing identification is a standard requirement for lease agreements, job applications, and financial verifications. Applicants frequently photograph their driver's license or passport and email the raw file directly to a landlord or human resources representative. This practice creates a permanent digital record of highly sensitive data sitting in the recipient's inbox. If that email account is ever compromised, the full ID card becomes available for identity theft.

Send only what they need

The first principle of document security is data minimization. You must determine what information the recipient actually needs to verify, and obscure the rest. A landlord typically needs to verify your full name, your date of birth, and your photograph to ensure you match the person standing in front of them. They do not need your full driver's license number, your document issue date, or your organ donor status.

Why a black box is not enough

Masking this unnecessary information requires caution. Many users open a scanned PDF in a standard document editor, draw black digital rectangles over their ID number and address, and save the file. This creates a false sense of security. A PDF is not a flat photograph; it is a container made of layered objects. The black rectangle is simply an object placed on top of the text layer. Anyone who receives the file can open it in a similar editor, select the black rectangle, and delete it, revealing the unredacted information underneath.

Even if you export the edited PDF, some software simply hides the text layer without destroying the data. A recipient can sometimes highlight the area under the black box, copy the invisible text, and paste it into a plain text document to read your ID number.

Flatten it: turn the page into pixels

To permanently destroy the masked data, the document must be flattened. Flattening converts the separate layers of text, images, and shapes into a single grid of pixels. The most reliable way to flatten a document is to convert the PDF into a standard image format like a PNG or JPEG. Once the file is an image, the black box and the text beneath it are merged into a single layer of pixels. The data beneath the box ceases to exist.

By running your file through PDF → Image, you can securely flatten each PDF page into a JPG or PNG without uploading the ID anywhere. Once the masked document is flattened into an image, it can be safely converted back into a PDF if the recipient requires that specific format.

Watermark with purpose and date

After masking and flattening, the document needs a watermark. A watermark restricts the future utility of the file if it falls into the wrong hands. Using a photo editor, write a line of text directly across the ID card. The text should state the specific purpose of the file and the current date. For example, write "Provided for 123 Main St lease application only - September 2026."

The placement of the watermark is critical. If you place the text in the blank white margin of the page, a malicious actor can easily crop it out. The watermark text must overlap key features of the ID, such as the edge of your photograph or the background pattern of the card, while leaving your name and date of birth legible. This makes the watermark extremely difficult to remove without visibly damaging the ID.

File names and cleanup

File naming hygiene is the final step before transmission. Modern digital cameras name files with sequential numbers, such as "IMG_4921.jpg." Some applicants rename the file to include their personal details, creating titles like "John_Doe_ID_123456789.pdf." Never put identification numbers, social security numbers, or full dates of birth in the filename. Use a generic, clear title like "John_Doe_ID_Redacted.pdf."

Once you have verified the recipient has received and processed your application, delete the digital working copies from your computer. Your phone or hard drive should not serve as a permanent archive for unencrypted, high-resolution scans of your identity documents. Because PDF → Image processes files directly in your browser, you never leave a temporary file on a remote server that you need to worry about deleting later. Keep the physical card secure in your wallet, and generate new, specifically watermarked digital copies only when the next application requires them.