Email encryption transforms readable content into a secure format, making it unreadable to unauthorised individuals.
Encryption Process: When you send an encrypted email, the content is scrambled using a cryptographic algorithm. This turns the readable text into ciphertext - a jumbled, unreadable format.
Types of Encryption: Depending on the email encryption type use, the point at which an email is encrypted, and the strength of the encryption, can vary greatly. For example:
TLS (Transport Layer Security): Encrypts the email during transmission between servers, but if it fails to establish a secure connection, it can leave email contents readable.
S/MIME (Secure/Multipurpose Internet Mail Extensions): Provides end-to-end encryption by using a pair of permanently held cryptographic keys, and is only possible if the sender and recipient have obtained a digital certificate.
AES-256 (Advanced Encryption Standard): Encrypts the email on the sender's device, remaining encrypted until decrypted by the recipient using military-grade security, regardless of the technology they use for email.
Decryption Process: Upon reaching the recipient, the email is decrypted back into readable text, provided they have the correct key or the credentials required to access the correct key.
This process ensures that even if an email is intercepted, its contents remain unreadable to anyone except the intended recipient.
Encryption Best Practices
How can you make sure the right emails are encrypted? Here are some email encryption best practices.
Matching Your Setup To Your Needs
Encrypting emails can range from manually encrypting individual messages to rule-based encryption based on the inclusion of different types of sensitive information.
Bulk, automated encryption for the delivery of information to recipients at scale might be necessary for some businesses.
You should ensure that the way you are able to initiate the encryption process matches how sensitive data is being sent.
Choose the Right Encryption Solution
Outlook users can encrypt emails natively, but this encryption is not suitable for most types of sensitive data.
Dedicated business solutions, like Mailock secure email, can provide additional features for exchanging sensitive messages.
If you're looking for a tool to protect emails to customers, it is especially important you choose a solution that works for them too.
The most common email clients including Outlook, Gmail, and iOS provide a level of basic encryption:
Most email providers offer TLS encryption as standard and optional S/MIME encryption with a digital certificate.
A Microsoft 365 E3 licence gives enterprise users additional functionality in the form of Microsoft 365 Message Encryption (MPME).
A key difference between the S/MIME encryption standard and the encryption available with MPME is compatibility.
Whereas the encryption offered as standard by providers requires the recipient's email client to be S/MIME compatible, MPME is more reliable, protecting emails regardless of a recipient's email provider.
"The rights management (MPME) feature is intended as a tool to prevent accidental misuse and is not a security boundary."
It must be noted that MPME's encryption strength is designed for prevention and not security and it is not suitable for the delivery of information to customers in high volumes due to rate limits.
For email encryption to protect sensitive enterprise customer communications, a dedicated secure email service is required.
Sam Kendall, an expert researcher, editor, and marketing specialist, has nearly a decade of experience helping B2B brands refine digital strategies and streamline implementation. He is passionate about user experience, demand generation marketing, and customer communications.