Q
Problem solve Get help with specific problems with your technologies, process and projects.

# Which public key algorithm is used for encrypting emails?

## Although PGP and S/MME both use public key encryption, Expert Joel Dubin explains PGP and S/MME's distinct approaches to e-mail coding.

Which public key algorithm is used for encrypting emails?

You can encrypt email using either Pretty Good Privacy (PGP) or S/MIME. Unfortunately you can't use both, because...

the two applications aren't compatible and use different methods for encryption. However, both use public key encryption at some point in their respective processes. Public key or asymmetric encryption is supposed to solve the fundamental problem of securely distributing a private key over a public medium like the Internet. It uses two keys: a public key, available to the world, and a private or secret key that is only kept by its owner. Both keys are needed to encrypt and decrypt the message. The system is secure because even though the two keys are mathematically related, they can't be derived from each other. Since only the public key, which is openly available but can't be used to decrypt the message by itself, is needed to encrypt a message, the private key doesn't have to be distributed in the wild, where it could be exposed and its secrecy compromised.

PGP was invented by Phil Zimmerman in 1991 and uses two asymmetric algorithms: RSA and DSA. RSA was named after its MIT inventors, Ron Rivest, Adi Shamir and Len Adleman. It uses key lengths ranging from 1024 to 2048 bits. DSA, or Digital Signature Algorithm, is a U.S. government standard which PGP uses to create a digital signature for a message to verify the authenticity of the sender.

S/MIME, on the other hand, also uses RSA and DSA, but only for providing digital signatures. S/MIME, unlike PGP, relies on the use of a certificate authority (CA) for storing certificate hierarchies, which are used for encrypting messages, instead of public key encryption. As a result, such encryption is only needed for digital signatures, when necessary.

• Visit our resource center for news, tips and expert advice on how to use SMIME/PGP encryption methods to secure email transmissions.
This was last published in September 2006

## Content

Find more PRO+ content and other member only offers, here.

#### Have a question for an expert?

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

#### Start the conversation

Send me notifications when other members comment.

## SearchCloudSecurity

• ### Cloudflare Access takes on VPNs with reverse proxy approach

Cloudflare takes inspiration from Google's BeyondCorp with a new service called Cloudflare Access, which aims to replace ...

• ### TLS 1.3: What it means for enterprise cloud use

The latest draft version of TLS 1.3 is out, and it will likely affect enterprises that use cloud services. Expert Ed Moyle ...

• ### The biggest cloud security threats, according to the CSA

The Cloud Security Alliance reported what it found to be the biggest cloud security threats. Expert Rob Shapland looks at how ...

## SearchNetworking

• ### ThousandEyes-Juniper pact focuses on hybrid WANs

ThousandEyes and Juniper boost visibility for hybrid WANs; IDC records sharp rise in cloud spending; and a vendor group issues ...

• ### ExtremeLocation latest addition to Extreme wireless portfolio

Extreme Networks is targeting retailers with a new set of services, called ExtremeLocation. The latest technology adds ...

• ### Take network configuration management tools to the next level

Script management systems and intent-based networking are driving the future of network configuration management tools, shifting ...

## SearchCIO

• ### Wayfair's chief architect talks AI-driven innovation, impactful IT

Wayfair sells home furnishings, but under the covers, it's a tech juggernaut. Chief Architect Ben Clark explains how AI-driven ...

• ### Synthetic data could ease the burden of training data for AI models

Sometimes it's better to manufacture training data for machine learning models than it is to collect it.

• ### CES 2018 for CIOs: Rise of the AI voice assistant class

What happens in Vegas doesn't stay there -- not at CES 2018, where AI voice assistants and sentient objects were ubiquitous and ...

## SearchEnterpriseDesktop

• ### Ten Windows 10 Fall Creators Update features to know

Microsoft introduced some significant changes to Windows 10 in the Fall Creators Update. The My People app, for example, lets ...

• ### Guard the line with Windows Defender features

The Windows 10 Fall Creators Update took Windows 10 security up a notch by adding advanced features to Windows Defender, ...

• ### Ready to master virtualization-based security in Windows 10?

Put your knowledge of virtualization-based security in Windows 10 on the line with this quiz covering the ins and outs of ...

## SearchCloudComputing

• ### Google Cloud Dedicated Interconnect offers VPN alternative

Google's Dedicated Interconnect enables an enterprise to privately connect its data center to the public cloud. Here's a ...

• ### Chip bugs hit cloud computing usage less than first feared

IT shops expected their cloud usage to flag due to recent chip bugs, but most environments survived the patches unscathed.

• ### Providers continue to push hybrid cloud technologies in 2018

The hybrid cloud market changes rapidly, as major cloud providers release new services to bridge private and public platforms, ...

## ComputerWeekly.com

• ### UK and France to collaborate on digital tech

The UK and French governments have joined forces to increase technology and innovation cooperation between the two nations

• ### Create security culture to boost cyber defences, says Troy Hunt

Security suffers when there is tension between software developers and security professionals, but it is common in many ...

• ### Nordic IT executive interview: Daniel Kjellén, CEO, Tink

Sweden could have a head start in the race to open up banking through the European Union’s PSD2 regulation

Close