Public Key Encryption

An example of how a bank might accomplish encryption.

Public Key Encryption

Starts with a large randomly generated number

A Key generating program/algorithm creates two mathematically bound

keys.

Private Public

Public Key Encryption

What the Public Key encrypts only the

Private Key can decrypt

Private Public

Trusted Third Party

The Third Party Service provides time-stamped Public Key

Certificates confirming the source (bank) can be trusted.

The Certificate is sent to your browser with the Public Key embedded when you select a

web page starting with HTTPS.

Your Browser

Checks the Certificate to ensure the time-stamp is still valid.

Uses the embedded Public Key to encrypt all of your input prior to sending information over the Internet. The encrypted result is unique to just this Public

Key and can not be decrypted by any other key except for the Private Key located at the bank.

The same Public Key used to encrypt a message can not decrypt its own input.

My SSN is: 123 45 6789

Public

Private

My SSN is: 123 45 6789

Public Key Example

Let's Look at Bank of America

1. Type URL http://bofa.com

2. Notice the URL changes to https://

3. Notice the key in the bottom right status bar

4. Click on "Tools" menu then "Page info"

5. Click on "Security" then "View Certificate"

6. Click "Details"

7. Scroll down until “Subject's Public Key” is displayed

8. Click on “Subject's Public Key”

Let's Look at Encryption

Go to the class web site http://reliablescribe.com/class

In the Internet Cloud click on “Test Encryption” A new page will display Type any text you wish in the field Click on “Submit” The display will show a simple encoding with a

fixed known key.