Difference between PGP and S/MIME
The security protocols PGP and S/MIME are created to secure the electronic mail facility. The primary distinction between these protocols is the type of algorithms utilized in their security mechanisms. PGP builds confidence between users by using either key rings or digital certificates. On the other hand, S/MIME makes use of digital signatures, message digests, encryption, etc.
In this article, you will learn about the difference between a PGP and S/MIME. But before discussing the differences, you must know about PGP and S/MIME with their advantages and disadvantages.
What is PGP?
PGP is an abbreviation for "Pretty Good Privacy". It is an open-source software program that is mainly designed for email security, and it was designed and developed by Phil Zimmerman. It offers the fundamental needs of cryptography. To secure the email, it employs many steps, including authentication, confidentiality, compression, email compatibility, segmentation, and reassembly. PGP includes a public key trust model and public key certificate management tools to implement and develop it.
PGP takes some steps to secure the email, and these steps are as follows:
1. Digital Signature
The message digest of the email message is generated using the SHA-1 algorithm, and the message digest is encrypted utilizing the sender's private key.
The email message and the digital signature are compressed together to decrease the final transit message size. The ZIP program is the best example of compression based on the Lempel-Ziv algorithm.
It uses a symmetric key to encrypt the compressed form of the message obtained from the compression.
4. Digital Enveloping
The receiver's public key is utilized to encrypt the symmetric key utilized in the encryption step. A digital envelope is created by combining steps 3 and 4.
5. Base-64 Encoding
Step 4's output is Base-64 encoded, where a lot of arbitrary binary inputs are converted into printable characters.
Advantages and Disadvantages of PGP
There are various advantages and disadvantages of a PGP. Some main advantages and disadvantages of a PGP are as follows:
What is S/MIME?
S/MIME is an abbreviation for "Secure/Multipurpose Internet Mail Extension". It is a secure enhanced variant of the MIME internet email format based on RSA Data security technology. Public key cryptography is utilized in this case to sign, encrypt, or decode the email digitally. The user obtains a public-private key pair from a trusted authority and then uses those keys appropriately with email programs. MIME replaced the SMTP protocol since it was limited to text and could only carry text messages. The user obtains a public-private key pair from a trusted authority and then uses those keys appropriately with email programs. MIME replaced the SMTP protocol since it was restricted to text, where only text messages were permitted to transmit. The restricted protocol SMTP was unable to communicate multimedia files and documents in many arbitrary forms because it employs a 7-bit ASCII representation of characters in an email message, which cannot represent special characters with values more than 127.
Structure of S/MIME
A MIME email message comprises a text message, some specific headers, and formatted text parts. Each segment may include an ASCII-encoded portion of data and the technique for decoding the data at the receiver's end. MIME headers provide the following information: MIME version, Content-ID, Content-Type, Content-Transfer-Encoding, and Content-Description.
Advantages and Disadvantages of S/MIME
There are various advantages and disadvantages of S/MIME. Some main advantages and disadvantages of S/MIME are as follows:
Key differences between PGP and S/MIME
Here, you will learn the various key differences between PGP and S/MIME. Some main differences between PGP and S/MIME are as follows:
Head-to-head comparison between PGP and S/MIME
Here, you will learn the head-to-head comparisons between PGP and S/MIME. The main differences between PGP and S/MIME are as follows:
PGP may only support text-based email, whereas S/MIME may support various forms of multimedia, and both use different key exchange mechanisms.