Encrypting vs. Signing with OpenPGP. What’s the Difference?

Many businesses are responsible for maintaining large amounts of confidential data, including customer records, medical records, financial reports, legal documents, and much more. It’s very common for these types of information to be transmitted via email. So how can you ensure confidential data transmitted via email is kept private? How can you ensure the integrity of transmitted data and that a message actually came from its purported sender?

Businesses need to ensure confidentiality, data integrity, message authentication (proof of origin), and non-repudiation (proof of content and its origin). These goals can be accomplished using MDaemon’s OpenPGP message encryption and signing services. Read on to learn more about the differences between encrypting and signing, and when each is used.

The Need for Encryption

 Businesses need to protect sensitive data and preserve confidentiality and privacy. Whether you work in healthcare, finance, legal, HR or education, chances are you’re familiar with the terms HIPAA or FERPA (among others). Businesses that fail to meet these regulations risk data breaches that can lead to lost revenue or legal action. To address these issues, businesses can use encryption to make their sensitive data unreadable to unauthorized parties.

The Need for Signing

In addition to data privacy, businesses may need to ensure that a message was not altered during transit, and that it actually came from the purported sender. These tasks are accomplished with message signing (adding a digital signature) using OpenPGP. Much like your handwritten signature, a digital signature can be used for authentication purposes, but also cannot be forged.

Signing a message helps ensure the following:

  • Data Integrity – That the message was not altered from its original form.
  • Message Authentication (Proof of Origin) – That the message actually came from the purported sender.
  • Non-repudiation – That the sender cannot deny the authenticity of the message they sent and signed with OpenPGP.

Encrypting vs. Signing – What’s the Difference?

So what are the differences between encrypting & signing? Let’s discuss each.

What is Encryption?

Encryption is the act of converting plain text to cipher text. Cipher text is basically text that has been scrambled into non-readable format using an algorithm – called a cipher. MDaemon’s implementation of OpenPGP encryption uses public key encryption (also known as asymmetric key encryption) to encrypt email messages and attachments.

So How Does Public Key Encryption Work?

Public key encryption uses public/private key pairs. If you want me to send you an encrypted message, you send me your public key, which I import into my encryption software (using the OpenPGP configuration screen in MDaemon, in this case). I encrypt the message with your public key. When you receive the message, you decrypt it with your private key. Even though your public key can be freely distributed and used to encrypt messages addressed to you, these encrypted messages can only be decrypted with your own private key. This private key must always be kept secret. Data encrypted with the public key can only be decrypted with its corresponding private key; conversely, data encrypted with the private key can only be decrypted with its corresponding public key. We’ll talk about why you would encrypt a message with your own private key in the next section when we discuss message signing.

Encrypting email with OpenPGP
Encrypting email with OpenPGP

Encrypting a message helps ensure that the message is kept confidential. The message remains in its encrypted format until it is decrypted with the recipient’s private key.

What is Message Signing with OpenPGP?

As I mentioned above, messages are encrypted with the message recipient’s public key and decrypted with the corresponding private key. Message signing, on the other hand, uses the sender’s private key to sign (encrypt) the message, and his public key is used to read the signature (decrypt). Message signing binds the identity of the message source to the message. This helps ensure data integrity, message authentication, and non-repudiation.

For example, if John wants to digitally sign a message to Michelle, he uses his private key to encrypt the message, and sends it (along with his public key if it hasn’t already been sent) to Michelle. Since John’s public key is the only key that can decrypt the message, the digital signature is verified by simply decrypting the message with John’s public key.

Signing with OpenPGP
Signing an Email Message with OpenPGP

Signing a message with OpenPGP ensures that the message was not altered in transit, that it did in fact come from the purported sender, and that the sender cannot deny the authenticity of the message they sent and signed with OpenPGP.

Message encryption & key management are explained in this tutorial video:
https://youtu.be/2fjyAAcHpMs?list=PLt-aAHf-ocsb0xDLb930tnPZZ9A1J19VG

More information on using MDaemon’s PGP encryption & signing features can be found in the following knowledge base article:

How to enable MDaemon PGP, configure who can use MDPGP, and create keys for specific users

http://www.altn.com/Support/KnowledgeBase/KnowledgeBaseResults/?Number=1087

Do you have questions? Let us know in the Comments section below!

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Stop Spam & Malware with SecurityGateway – New SlideShare Presentation

Can you imagine what life would be like if we didn’t have anti-spam and anti-virus protection on our email servers and gateways? Users would be so flooded with spam, phishing attempts and malware that they’d have to scroll through many pages of email messages before finding a message that’s legitimate. A good anti-spam/anti-virus mail server or gateway will filter out the vast majority of this nonsense so that the end user can focus on his job.

Most mail servers have some form of built-in spam protection, however, administrators are often faced with these challenges

  • Not enough security features on the mail server to catch many of today’s evolving threats
  • The need for an extra layer of defense between the mail server and the internet
  • Lack of reporting features, which can be used to assess the effectiveness of your email security solution
  • Cumbersome configuration & confusing settings

SecurityGateway was created to address these issues. Many small-to-medium businesses trust  SecurityGateway to protect their inbound and outbound email from spam, phishing attempts, and malware.

The following is a brief presentation that describes SecurityGateway’s features.

 

Would you like to learn more about SecurityGateway? Click here to visit the SecurityGateway overview page, or click here to download your free trial.

 

 

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