This is a general overview of the type of security available,
encrypted message exchange, and a sample use of public key
encryption.
Secure systems on an
open network rely on encryption and authentication to
provide transaction security.
Secure servers, such as your Purveyor
Encrypt WebServer, support both secure and standard Web
transactions.
Internet Security actually consists of three
distinct services: access security, transaction security, and
authentication.
Access security refers to a
corporation's ability to protect its computers, memory, disk,
printers and other computing equipment from unauthorized use.
Commonly referred to as access controls, this type of security
allows you to control user access to files and directories.
The Purveyor Encrypt WebServer family provides
access control to files and directories via its access control
options.
The Secure Socket Layer (SSL) is a protocol for
transaction security on the World Wide Web.
Transaction security or communications security
refers to the ability of two entities on the Internet to conduct
a transaction privately, and with authentication and digital
signatures if required. Commerce on the Internet and the World
Wide Web fundamentally depends on transaction security.
Authentication is the process of verifying the
identity of someone or something. For example, authentication
can ensure the identity of parties on each end of a communication.
Authentication techniques require that a person or
program prove its identity, usually by using a password, key card,
fingerprints, or a "digital" signature. Whichever is used,
it must be unique to only that person.
Authentication techniques can be quite simple,
very complex, or somewhere in-between. The traditional use of
passwords or pass phrases is a middle of the road example of an
authentication method.
The Secure Socket Layer (SSL)
protocol provides transaction security between two communicating
applications (a browser and server). The protocol authenticates
the server and, optionally, the browser.
SSL can layer on top of any transport protocol,
such as TCP/IP, but SSL is not TCP/IP dependent. SSL runs under
application protocols such as HTTP and FTP.
TCP/IP is the communications protocol for most
Internet applications, such as e-mail, Netnews, and the Web.
TCP/IP provides reliable transport between two parties on the
Internet.
With SSL, security properties are attached
to the link or channel of communication between two parties,
not to the documents themselves.
An SSL server:
SSL makes the channel between a
browser and a server:
SSL provides for private
communications. SSL with HTTP can include usernames and
passwords in encrypted messages for authentication purposes.
Because SSL and HTTP use different port numbers
(443 and 80 respectively, by default), your Purveyor Encrypt
WebServer can handle secure and standard browsers simultaneously.
This means that the server provides some browsers
unencrypted information and others with encrypted information. You
can identify SSL by a URL that begins with https://. Some browsers
display security icons that indicate whether a transaction is secure.
Secure systems on an open network rely
on encryption, authentication, and integrity support to
provide transaction security. Encryption ensures against
eavesdroppers, authentication ensures against impostors,
and integrity ensures against modified messages.
Encryption
transforms data into a form that can be read only by persons who
have a key to decrypt the data. Encryption ensures privacy by
keeping information hidden from anyone for whom the information
is not intended.
For example, the Widget Works company might have
an opportunity to provide super widgets for a large trade show and
wants to submit a bid over the public network. Widget Works also
wants to hide this information from any rivals. The company decides
to use encryption. Figure 32 shows
what happens.
Figure 32 Data Encryption
Internet Security Services
Access Security
Transaction Security
Authentication
What is SSL?
SSL Approach to Security
SSL mandates the channel of communication
between two parties as private and authenticated and encrypts
the entire data stream between the browser and server. There
is no negotiation between browsers and servers concerning
applying security characteristics to individual documents.
Relative Advantages of SSL
Transaction Security on an Open Network
Encryption Support
The Purveyor Encrypt WebServer provides extended access control to files and directories on the server. The Remote Server Management (RSM) features let you set encryption requirements to access files and directories. The WebServer also verifies the integrity of digitally signed documents (usually queries) when it receives them.
Authentication takes place by using agreed-upon keys to generate and verify the message digest. The message digest consists of summary information that is transmitted with the message and is uniquely derived from the message contents. The WebServer uses the:
Authentication lets the receiver of a message verify that the sender is indeed who they purport to be. Using a digital signature is one method of authentication.
A digital signature is a unique group of random pieces of data. A digital signature serves as a signature for an electronic message in the same way that a handwritten signature serves as a signature for a printed message.
An authentication system consists of two parts, providing a method to:
Digital signatures can be neither forged nor repudiated. Anyone applying their digital signature to a message cannot later disown it by claiming forgery.
SSL uses X.509 certificates for authentication, RSA as its public-key cipher, and one of RC4-128, RC2-128, or DES as its bulk symmetric cipher.
The Purveyor Encrypt WebServer provides for the management of multiple keys. The server stores keys locally and they are accessible with a user-specified password.
On some client systems, you can select from keys of the appropriate type for a given transaction.
In public-key systems, each party has a key pair; a public key and an associated private key. The owner of a key pair distributes the public key to any sender that wants to communicate with the owner. However, the owner keeps the private key absolutely secret.
The sender of a message uses the receiver’s public key to encrypt the message (Figure 33). The receiver uses the private key to decrypt the message.
For example, Widget Works wants to let customers use their credit card numbers to order products over the Web. They want their customers to know that no one else can read the credit card information. To accomplish this, Widget Works generates a public and private key pair. The public key is made known, but Widget Works stores the encrypted private key only on its system.
Figure 33 Using Public Key Encryption
In public-key systems, users share only half of the encryption mechanism (the public key) among the parties to a communication. The private key never leaves the possession of its owner. Neither key is of any value without the other.
Encryption protects against eavesdroppers and impostors. The server encrypts messages sent to a browser and decrypts messages sent from a browser.
With public key encryption, you can exchange encrypted messages in both directions between server and client. There is no need for a browser public key.
Key Requirements
Data is encrypted with session key. The session key is in turn encrypted with public key cryptography for transmission.
A secure server can support a number of functions including:
Purveyor supports the use of one private key per virtual server. You store this private key and its matching public key on the local machine. You provide key security by encrypting the server’s private key using a Webmaster or system administrator-specified password.
You can use an SSL compatible secure browser or a program provided with a secure server to generate the public/private key pair and initiate the corresponding public key certificate process (see Figure 34). An RSA public key can be from 512 to 1024 bits long.
Figure 34 Public/Private Key Generation
Local security configuration files and CGI
programs generate secure message headers. They also configure
the server to specify the encryption properties required for a
query response.
There are several SSL security-related
CGI environment variables. These allow application developers
to integrate a secure server, such as Purveyor, with their CGI
programs. These variables let the CGI programs learn:
A Distinguished Name is
a collection of attributes (country, state, company name,
etc.) assigned to an entity for use in electronic commercial
applications. The term is originally defined in the CCITT X.500
protocol.
Part III contains information specific to
installing and managing your Purveyor Encrypt WebServer for
OpenVMS. The chapters included in this part are
Encryption and Signature Control
Security-Related CGI Environment
Variables
