S/MIME: Encrypting and Signing Emails for Maximum Security

 S/MIME

Secure/Multipurpose Internet Mail Extensions (S/MIME) is an industry standard that encrypts and digitally signs emails to ensure their integrity and security:

• Encryption: Protects the contents of emails
• Digital signatures: Verifies the sender's identity
• Message integrity: Ensures the email's contents are not altered
• Non-repudiation: Provides a way to prove the origin of the email
• Authentication: Verifies the identities of both the sender and recipient

S/MIME is compatible with most enterprise email clients, including Outlook for iOS and Android. To add or remove a digital signature from a message in Outlook on the web, you can:

• Go to the top of the message
• Select More options > Message options
• Select or deselect Digitally sign this message (S/MIME)

Digital Signature: Exam notes CompTIA Security+

 Digital Signature

Listed below are the items you need to know for the exam:

Digital signatures provide:

• Non-repudiation
• Authentication
• Integrity

Creating the digital signature is a 2 step process:

• First, hash the email/message
• Second, the private key digitally signs (encrypts) the hash

The digital signature is created with the "sender's" keys. 

The digital signature is an encrypted wrapper for the sender's public key.

The recipient's system extracts the public key and decrypts the digital signature to validate the sender.

RSA and DSA (Digital Signature Algorithm) are used to create digital signatures.