Does Email Encryption Encrypt Attachments?  

Thanks to the Internet, businesses now have an easier way to communicate with their internal and external stakeholders. However, one downside of online communication is that you cannot assure the security of your messages once it gets sent over the network. Even though you have firewall protection, it doesn’t necessarily protect all the contents of the email. Data encryption is still the best way to shield your email from unauthorized access from outsiders. 

So how does email encryption work for attachments? General encryption methods like TLS only provide a basic level of protection and there’s still a risk that email attachments can be compromised. Using end-to-end encryption, S/MIME certificates, and PGP encryptions systems are more ideal for sending emails with secure attachments. 

Are Your Attachments Secure When Sending Emails?  

Any information that’s exchanged over the internet always comes with some form of risk, especially now that hackers and cybercriminals are utilizing advanced tactics to pry over and steal sensitive data. Encryption is the most critical layer of cybersecurity to make sure that your emails won’t be easily intercepted and fall under the hands of thieves. 

However, not all encryption methods can automatically protect files and documents that are attached to the message. Using the most basic form of encryption, which is known as TLS or transport layer security, can’t guarantee that email attachments can remain hidden from scammers and online attackers. It may also not protect against phishing attempts, bad links, and malicious files that contain viruses or malware. 

How Does TLS Email Encryption Work? 

TLS encryption is one of the most popular forms of internet security protocol used to establish the security and privacy of digital communications. Most email providers today such as Gmail, Yahoo Mail, and Microsoft are supporting TLS to encrypt messages that are shared on their platforms. Likewise, if you see a padlock icon on the side of the address bar, it means that the website is using TLS security to protect your current browsing session. 

When it comes to sending emails, this encryption method uses cryptography methods to secure the message before being sent. This key is provided to both the sender and receiver. Before sharing the email on the network, the sender uses the session key to secure the email and the receiver will input the same key to decrypt its contents. 

However, it can still be hijacked by unwanted third parties while it’s being transmitted over the servers even if the email itself is protected. Furthermore, this encryption protocol is only effective if the recipient has enabled TLS on their end. If they’re not supporting TLS services, they will receive the unencrypted message and there’s a possibility that it may have already been accessed or tampered with by hackers before they opened it. 

Best Email Encryption Systems For Securing Attachments 

When it comes to email encryptions, there are other options that offer complete security for attachments. These encryption solutions are recommended for use in businesses and enterprises that frequently exchange and send highly sensitive documents and data. Here’s an overview of some of the best encryption methods for email attachments: 

1) End-to-end encryption (E2EE) 

Considered the gold standard for encrypting online communications, the end-to-end encryption solution or E2EE provides strong protection for emails and makes its contents inaccessible to anyone other than its sender and the intended receiver. This type of security encryption ensures that your emails and their contents are safe from the moment that they’re being sent and while they’re passing through different servers up until it reaches their destination. 

When you want to include an attachment with your email, the selected file is first converted into an unreadable format that can only be opened by a digital key. Without this key, the recipient will not be able to download and save the attached file. So even if the email ends up on the wrong server or gets intercepted and stolen along the way, the hackers won’t be able to use the attachments to their benefit. 

There are 2 known types of end-to-end encryption: 

  • The first one is symmetric encryption which is a simple and straightforward method of protecting emails. It uses a single symmetric key to encrypt and decrypt the exchanged data from ciphertext. The key is typically not shared through the servers but can be sent by the host through other external means. When using symmetric encryption, it’s best that you provide the key only to authorized personnel within the company.

  • The other type of E2EE is asymmetric encryption which is sometimes called public key cryptography. This encryption method uses two separate keys for encryption and decryption. One of the keys is shared with the public and it’s used for securing the data while the other key for opening the attachment is randomly generated. It has the advantage of being more secure than symmetric encryption since it uses different keys for the encryption process. 

2) S/MIME Certificate or Secure/Multipurpose Internet Mail Extensions 

S/MIME is one of the most common and easier ways to send and secure email attachments. This encryption protocol relies on a third party authority to check the digital certificate and validate the identity of the sender and the receiver. This method is effective in preventing threats of email spoofing or phishing scams.  

To secure an attachment with S/MIME, the sender and receiver should have the S/MIME certificate installed on their email clients. The sender will lock the attachment file using the recipient’s specific key while the other party will decrypt the email using their private key. There is also a digital signature that can be included in the email to ensure the legitimacy of the sender. 

Most email providers on the web like Gmail, Outlook, and iOS systems already support S/MIME encryption. 

3) PGP or Pretty Good Privacy Encryption

This is one of the oldest methods of encryption which was introduced in 1991 but until today, many individuals and companies are using this program for sending sensitive data over emails. The process of encryption with PGP features a combination of data compression, public-key cryptography, message authentication, and confidentiality. It’s much more comprehensive and offers strong security for your emails. 

Similar to S/MIME, PGP requires the use of a public and private key for encrypting and decrypting. However, unlike S/MIME where the keys can be exchanged over their email clients or the company’s database, senders using PGP must get the recipient’s key from a decentralized service or external server. Some of the common email providers that support PGP  encryption are Yahoo Mail and Android. 

How To Encrypt Attachments For Different Email Providers

Although most web-based email providers support S/MIME and PGP encryption, they don’t have a built-in program so you need to install and enable a third-party extension. Here are the ways on how you can activate and send encrypted attachments: 

Google Mail  Yahoo Mail  Microsoft Outlook
  • Set up the S/MIME host by going to Google Admin console and uploading the certificates to Gmail
  • After enabling the S/MIME, reload the Google Mail accounts and you should already see a green lock in the Subject line of the email
  • Exchange keys with email recipients by sending S/MIME signed messages which will already include the digital signature and keys to encrypt or decrypt future messages
  • For Yahoo Mail services, you may need to download a third-party program like Mailvelope to encrypt with S/MIME or PGP 
  • Upon downloading, configure and enable the encryption settings that you prefer 
  • When creating a new message on Yahoo Mail, click the third-party plug-in and click Encrypt to apply the security settings to your message 
  • For Outlook messages, you need to have the certificate already installed on your computer for easy configuration on Outlook 
  • Once you have the S/MIME certificate set up, go to Outlook and open the Trust Center Settings in the File menu
  • Choose Email Security then go to Encrypted Email. Under Certificates and Algorithms, enable the S/MIME certificate
  • When composing the email, you can simply select the Encrypt with S/MIME  

Secure Your Data and File Sharing With Abacus IT Solutions 

Email encryption is an important layer of security that protects your businesses’ communications and ensures the integrity and confidentiality of all your pertinent data. At Abacus, we can help you set up the best encryption solutions to strengthen your defenses against harmful threats and breaches. 

We are committed to providing excellent and reliable IT solutions for all your current and future needs. Our team of IT experts and friendly support staff are always ready to answer your cybersecurity queries and can help address any potential risks before they escalate to serious issues. Contact us today to learn more about our services and security plans. 

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The Abacus Blog Team
At Abacus IT, our blog is authored by a team of IT experts with a wealth of experience in various facets of technology. Our primary blog author is a seasoned IT professional with over 20 years of experience in the industry. With a deep understanding of cybersecurity, cloud solutions, network infrastructure, and IT management, our author provides valuable insights and actionable tips to help you optimize your IT operations.

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