The world of encryption

THE

WORLD OFENCRYPTION

ABSTRACT

THIS PRESENTATION IS JUST PROVIDING THE BASIC CONCEPTS OF THE DIGITAL

CERTIFICATES, AND DIGITAL SIGNATURES WITHOUT PROVIDING ANY TECHNICAL

SOLUTION OR PREFERABLE TECHNOLOGIES.

ENCRYPTION

Encryption is the conversion of data into a form, called a CIPHER Text.

The use of encryption/decryption is as old as the art of communication.

Encryption/decryption is especially important in wireless communications.

Encryption/decryption is a good idea when carrying out any kind of sensitive transaction.

Ex: A credit-card purchase online, or the discussion of a company secret between different departments in the organization.

TYPES OF ENCRYPTION

PRIVATE KEY ENCRYPTION means that each computer has a secret key (code) that it can use to encrypt a packet of information before it is sent over the network to the other computer.

PUBLIC KEY ENCRYPTION uses a combination of a private key and a public key.

The key is based on a hash value. This is a value that is computed from a base input number

using a hashing algorithm.

DIGITAL SIGNATURES

A DIGITAL SIGNATURE OR DIGITAL SIGNATURE SCHEME IS A MATHEMATICAL SCHEME FOR DEMONSTRATING THE AUTHENTICITY OF A DIGITAL MESSAGE OR DOCUMENT.

A DIGITAL SIGNATURE CAN BE USED WITH ANY KIND OF MESSAGE, WHETHER IT IS ENCRYPTED OR NOT, SIMPLY SO THAT THE RECEIVER CAN BE SURE OF THE SENDER'S IDENTITY AND THAT THE MESSAGE ARRIVED INTACT.

CREATION OF DIGITAL SIGNATURES

a digital signature scheme typically

consists of three algorithms:

• hashing algorithm.• signature generation algorithm• a signature verifying algorithm that, given a message, public

key and a signature, either accepts or rejects the message's claim to authenticity.

METHODS OF ENCRYPTION BASED ON PRIVACY

•a message may be digitally signed, but not encrypted

•a message may be encrypted first, then digitally signed

•a message may be digitally signed first, then encrypted

Encryption scrambles or modifies a message or document so it cannot be read and understood, except by the intended recipient.

A key is necessary to reverse the scrambling or modification, to make the message readable.

PREREQUISITES TO CREATE A DIGITAL SIGNATURE

• Public-private digital key pair

• Certificate Authority.

• The public key certificate creates proof of the identity of the signer by using the services of a certificate authority.

• A certificate authority uses a variety of processes to associate the particular public key with an individual.

• The combination of public key and proof of identity result in a public key certificate - also called a signer's certificate.

HOW IT WORKS?

DIGITAL SIGNATURE VERIFICATION

SECURE SOCKET LAYER (SSL)

SSL (Secure Sockets Layer) is a standard security

technology for establishing an encrypted link between a

server and a client—typically a web server (website)

and a browser; or a mail server and a mail client

Where Do Certificates Come In?

All browsers have the capability to interact with secured web

servers using the SSL protocol. However, the browser and the

server need what is called an SSL Certificate to be able to

establish a secure connection.

What is an SSL Certificate? How Does it Work?

SSL Certificates have a key pair: a public and a

private key. These keys work together to

establish an encrypted connection. The certificate

also contains what is called the “subject,” which is

the identity of the certificate/website owner.

How Does it Work?

• To get a certificate, you must create a Certificate Signing Request (CSR) on your server.

• This process creates a private key and public key on your server.

• The CSR data file that you send to the SSL Certificate issuer (called a Certificate Authority or CA) contains the public key.

• The CA uses the CSR data file to create a data structure to match your private key without compromising the key itself. The CA never sees the private key.

Certification Authority (CA)

•A trusted agent who certifies public keys for general use (Corporation or Bank).

–User has to decide which CAs can be trusted.

•The model for key certification based on friends and friends of friends is called “Web of Trust”.

–The public key is passing from friend to friend.

–Works well in small or high connected worlds.

–What if you receive a public key from someone you don’t know?

(CA MODEL) TRUST MODEL

Root Certificate

CA Certificate

Browser Cert.

CA Certificate

Server Cert.

SSL Walkthrough

Client

Browser connects to website

Web Server

Step 1: Client accesses website

Client

Server responds with Certificate and key Web Server

Step 2: Server responds with Certificate

Client Web Server

CA

Client verifies certificate with CA

Step 3: Client verifies with CA

Client Web Server

Random Key

Client sends a random key to server encrypted with the public key

Step 4: Client sends random key to server

Client Web Server

Random Key

Step 5: All communications are now encrypted with the Random key

What is the difference between Server Certificate and Client Certificate?

How can I differentiate between them?

How does IIS distinguish between Client and Server Certificates?

Can I use a Server Certificate as a Client Certificate or Vice-Versa?

References

https://www.globalsign.com/en/ssl-information-center/what-is-an-ssl-certificate/

https://www.evsslcertificate.com/ssl/description-ssl.html

http://www.techtarget.com/

http://www.symantec.com/connect/blogs/client-certificates-vs-server-certificates-what-s-difference

http://blogs.msdn.com/b/kaushal/archive/2012/02/18/client-certificates-v-s-server-certificates.aspx

http://blogs.msdn.com/b/kaushal/archive/2010/11/05/ssl-certificates.aspx