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Ehsan Asdar / 2.10.2023Home / Email Security

How to encrypt a PDF file for email and send your attachments securely

Sending sensitive information doesn’t have to carry privacy risks. Learn how to encrypt a PDF file for email and ensure carefree file transfer.
Encrypted PDF icon.
Sharing private information online makes most people uneasy. According to statistics, 84% of people in the U.S. are concerned about online security, while 37% have experienced data breaches. If you’re emailing sensitive personal or business information, you should go the extra mile to keep it safe.Securing your attachments is crucial to protecting confidential data, so this guide will show you how to encrypt a PDF file for email correspondence. We’ll explore:You’ll also discover how Skiff helps you keep all types of files safe.
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How to send a secure PDF via email

There are several ways to protect your PDFs from unauthorized access:
  1. Password-protect your file before sending it
  2. Send a secure PDF using your email service provider’s (ESP’s) built-in security features
  3. Use an encrypted email service
Each option has specific benefits and drawbacks, so we’ll explain them in more detail to help you send private emails without concerns.

How to email password-protected PDF files

A common way to secure a PDF is to password-protect it before sending. Most users’ preferred PDF viewer and editor is Adobe Acrobat, which comes with useful security features.Encrypting your file with Acrobat involves a few quick steps:
  1. Open your file and go to Tools > Protect > Encrypt > Encrypt with Password
  2. Click on Require a password to open the document
  3. Type in your password
  4. Under Compatibility, select the appropriate Acrobat version. It must be the same as the recipient’s so they can open the PDF. Note that different Acrobat versions use varying encryption standards:
Acrobat version Encryption standard
6.0 and later 128-bit RC4
7.0 and later 128-bit AES
Acrobat X and later 256-bit AES
  1. Select Encrypt all document contents (you can also choose to only encrypt metadata or file attachments, but encrypting all contents is the safest option)
  2. Confirm your choices, retype the password, and click on OK
The above option is only available to Acrobat Pro users. The good news is that Adobe offers something similar if you use the free version or don’t use their software at all.

How to encrypt a PDF file for email for free with Adobe’s online protection tool

Adobe’s online tool lets you turn any PDF document into a password-protected one. Here’s how to use it:
  1. Head to Adobe’s online PDF encryption tool
  2. Click on Select a file and choose the PDF you want to protect
  3. Enter a strong password and confirm it
  4. Download the protected file and attach it to your email
While password protection is a solid way to limit access to your file, it leaves a significant loophole—you must share the password with the recipient. If email is your only form of communication, you won’t have another option but to send the password along with the file, which defeats the purpose of setting one in the first place.You can arrange another way of password exchange through SMS or a third-party app, but doing so can complicate the process and lead to additional security risks by increasing the potential attack surface.

How to encrypt a PDF for email using your provider’s security settings

Most major email service providers enable you to send secure emails and protect your attachments. They safeguard the entire email rather than the attachment alone, which increases the security of your digital correspondence.
Using Gmail as an example, you can protect your email through the following steps:
  1. Click on Compose to create a new email, and attach the PDF you want to send
  2. In the bottom row, click on the lock icon to turn on Confidential mode
  3. Chose the expiration period from the available options
  4. Select the password option:
  • SMS passcode—The recipient will get the passcode to their phone
  • No SMS passcode—Gmail users can open the email without restrictions until it expires, while non-users will get the passcode via email
  1. Click on Save and send your email
The main drawback of this method is that you can’t choose your password—Google does it for you. This means you don’t get as much confidentiality as the feature’s name implies because Google stores the password and can access your email.Other providers offer similar features, adding basic privacy to your emails. The problem is that none of them offer enough protection from third parties or cyberattacks. To ensure your PDF reaches the recipient without data breaches, you should choose an email service with ironclad encryption.

Encrypt a PDF for email without hassle with the right provider

Password PDF protection is always welcome, but it doesn’t ensure your file reaches the recipient safely. To make this happen, your email service provider should offer comprehensive and automatic email encryption.Most Big Tech email services use TLS (Transport Layer Security) encryption protocol, which is only slightly safer than the completely unsecured SMTP (Simple Mail Transfer Protocol). It protects your emails while they’re moving between servers by scrambling their contents into unintelligible strings of characters. If an email is intercepted, the attacker won’t be able to read its contents.This method seems secure enough at first glance, but it begs two questions:
  1. Are your emails also invisible to providers?
  2. Does this encryption type protect emails stored on servers?
The answer to both questions is no. Email service providers like Gmail and Outlook create and store the decryption keys on their servers, so they can see the contents of your emails. If the servers are attacked, your sensitive information is at a significant risk because TLS doesn’t protect data at rest.To keep your correspondence safe at every point between you and the recipient, you need end-to-end encryption (E2EE). It can secure your emails in two ways depending on the type:
  • Symmetric E2EE— Uses one key for encrypting and decrypting messages that gets shared among users
  • Asymmetric E2EE—Uses two keys—a public key for encrypting emails and a private one for deciphering the contents. As the decryption key is safely stored on a user’s device rather than the provider’s server, nobody but the recipient can access your messages or attachments
Encrypt your emails for safe communicationSafely transfer your PDF files with Skiff's E2EE Drive
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How to choose your E2EE email provider?

Many email services promise solid E2EE, but only a handful check all the necessary boxes. Your provider should combine airtight security with ease of use, which most fail to achieve.A good example is Gmail’s E2EE. It’s only available to paid G Suite users and relies on the S/MIME protocol, a widely-used E2EE standard. To start using it, you must:
  1. Buy the certificate separately
  2. Configure it in your Gmail settings, which is inconvenient and complex for users who aren’t tech-savvy
By moving beyond Big Tech, you’ll find several privacy-first providers that don’t involve hefty investments or bothersome setups. You should still look closely at their security and privacy standards, as many popular options use PGP (Pretty Good Privacy), which was tied to significant vulnerabilities alongside S/MIME.If you need an E2EE solution that implements the most advanced cryptographic techniques without sacrificing the user experience, Skiff will meet all your needs.

How Skiff Mail protects your files and correspondence

Skiff Mail uses two separate keys to ensure your emails and attachments are only accessible to the recipient. Every email is encrypted using the public key, and the private key never leaves the user’s device. As only the recipient has the decryption key, nobody—not even Skiff’s team—can read the emails but them.You don’t need to manually configure any certificates or settings—all security standards are built-in and predefined, so you can enjoy outstanding privacy from the moment you create the account. Skiff went above and beyond to create a straightforward, intuitive user interface that every user can navigate easily, regardless of their tech skills.Skiff Mail is jam-packed with useful features to provide smooth file sharing and correspondence:
  • Unlimited free search—Typically reserved for paid solutions, the thorough email and text search function is available for free with Skiff
  • Crypto integrations—The platform integrates with reputable wallets to provide safety and anonymity of your online correspondence and crypto transactions:
  • 10 GB of free storage—Store and manage your PDFs in an end-to-end encrypted drive
  • 4 Skiff.com aliases—Direct messages from multiple accounts into one inbox and manage them effortlessly
  • Transparent and open source—Skiff’s code is open for reviews and contributions by developers. Read the whitepaper for a deeper insight into the platform’s security practices

Take your file management to the next level with Skiff’s diverse product suite

Besides secure email, Skiff offers three end-to-end encrypted products you can use to complete your work without worrying about security—Skiff Pages, Skiff Drive, and Skiff Calendar.Check out the table below for detailed descriptions:
ProductOverview
Skiff PagesWrite and edit docs in real time and collaborate with your team from anywhere in the world in a secure environment. Simplify your workflow with text search, link sharing, and various other useful features
Skiff DriveUpload, share, download, and store files of any type across all your devices and retain full control over who gets to access them. Skiff integrates with the InterPlanetary File System (IPFS) to ensure full data ownership
Skiff CalendarSchedule events and sync your calendar with iOS and Android devices. Skiff Calendar lets you add and remove features so that you can tailor it to your needs

Create a free account and start sharing files securely

Skiff offers confidentiality from the moment you sign up. You don’t need to leave any personal details to get started—creating an account takes three quick steps:
  1. Visit the signup page
  2. Choose your account name and password
  3. Start using Skiff’s privacy-first products
You can use Skiff for free without time limits, and the plan is robust enough to give average users all the tools necessary to stay safe online. If you’d like to expand your workflow or unlock extra features, you can choose between three paid plans:
  • Essential—From $3/per month:
    • 10 aliases
    • 1 short alias
    • 1 custom domain
    • 15 GB of storage
  • Pro—From $8/per month:
  • Business—From $12/month:
    • 15 aliases
    • 1 short alias
    • 5 custom domains
    • 1 TB of storage

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