The BCC email feature helps to quickly communicate with several recipients while maintaining their privacy. It’s certainly more elegant than sending the same email a bunch of times to different contacts, although not as transparent as CC. While BCC has its perks, misusing it can lead to serious security risks.
In fact, the ICO has consistently ranked failure to use BCC correctly among the top non-cyber security breaches reported since 2019(new window).
According to the UK’s Information Commissioner’s Office (ICO)(new window), improper use of BCC has led to over 1,000 data breaches in the public sector as of October 2023. Many of these incidents involved highly sensitive cases, such as communications related to domestic abuse survivors and medical patients, where exposing recipient information could have severe consequences.
In this guide, you’ll learn how to use the BCC email feature effectively, avoid common mistakes, and keep your emails secure while protecting your the privacy of your recipients with Proton Mail(new window).
What does BCC mean in email?
BCC in email means “Blind Carbon Copy.” It’s an email field where you can enter the addresses of recipients who will remain hidden from each other. Unlike the TO and CC fields, which display all recipient addresses, BCC ensures that each recipient only sees their own name in group communications. It’s particularly used in professional settings.
Here’s the difference between TO, CC, and BCC:
- TO: Primary recipient(s) — Everyone sees who’s receiving the email.
- CC: Secondary recipient(s) — Also visible to everyone.
- BCC: Recipients stay hidden from each other.
When should you use BCC?
BCC is particularly useful in situations where you want to protect the contact details of recipients and prevent unnecessary email clutter. A classic BCC email example is sending a product update to customers — you just have to enter their email addresses in the BCC field.
Here are some common use cases for BCC:
- Sending mass emails, event invites, and announcements. Interestingly, research(new window) shows that most BCC emails contain only 1 to 5 recipients, suggesting it’s used more for smaller groups rather than huge mailing lists.
- Sending internal corporate emails to multiple employees or stakeholders.
- Communicating with clients and avoiding accidental “Reply All” threads.
- Keeping someone in the loop privately, like discreetly sharing an email with a manager or HR without letting the main recipient know. Or, a manager might BCC themselves on an email sent to a client.
Security considerations when using BCC
Despite the benefits of using BCC, there are certain risks you should be aware of:
- Exposing recipient lists: A common mistake is forgetting to use BCC when it’s absolutely necessary, which can lead to data breaches and compliance issues under data protection laws such as GDPR. For instance, in 2018, 3,000 individuals had their personal data exposed(new window) due to senders incorrectly using CC instead of BCC. This resulted in six major data breaches, with an average of 494 people affected per incident.
- Spam filtering issues: Sending an email with too many BCC recipients can trigger spam filters because it resembles bulk mailing, which is often associated with spam behavior. For example, the Proton Mail free plan limits you to sending 50 emails per hour and 150 emails per day, with each BCC address counting as a unique email. These mail sending limits help not only to prevent abuse but also to make sure your emails reach the recipient’s inbox without being flagged as spam.
- Phishing scams: Cybercriminals often exploit the BCC email feature to make phishing attacks look more convincing. By hiding the recipient list, they can send the same message to multiple recipients while making it seem like it’s meant just for you. The goal is to lower suspicion and make it more likely that you’ll click malicious links or share sensitive information.
Safely send BCC emails with Proton Mail
Proton Mail is a secure email service that protects all your emails with end-to-end encryption, including those sent or received via BCC, so only you can read them — not even we have access.
To help keep your inbox safe, Proton Mail includes advanced anti-spam tools, such as PhishGuard, which protects against phishing attacks by detecting and blocking fraudulent emails. Plus, we never show ads or scan your emails for advertising purposes — all Proton apps are solely funded by our community of paying subscribers.
If you don’t already have a Proton Mail account, you can easily move all your data, including emails, calendars, and contacts, using the Easy Switch feature.
We believe privacy should be internet’s default setting. That’s why we’ve built an encrypted ecosystem designed to protect your emails, passwords, internet connections(new window), cloud storage(new window), calendar, and digital assets.
