Cisco Cisco Web Security Appliance S170 Guia Do Utilizador

(Optional) Import custom root certificates. Optionally, you can import one or more custom root 
certificates so the Web Proxy can recognize additional trusted root certificate authorities used by 
HTTPS servers. For more information, see 

When the HTTPS Proxy is disabled, the Web Proxy passes through explicit HTTPS connections and it 
drops transparently redirected HTTPS requests. The access logs contain the CONNECT requests for 
explicit HTTPS connections, but no entries exist for dropped transparently redirected HTTPS requests. 

This book uses many terms from digital cryptography. This book also includes sections with background 
information about HTTPS and digital cryptography for reference only. For a list of the terms and 
definitions used in this book, see 

. For an overview of HTTPS the 

protocol, see 

. 

To understand how encryption and decryption works, you need to understand a little bit about 
cryptographic encoding techniques. 

 describes some terms used in cryptography that are 

discussed in this chapter. 

Certificate authority

An entity which issues digital certificates for use by other parties. 

Certificate authorities are sometimes referred to as trusted third parties. 
Certificate authorities are typically commercial companies that charge for 
their services. However, some institutions and governments have their own 
certificate authorities, and some offer their services for free.

Cipher

An algorithm used for encoding and decoding text to make it unreadable to 
any system without the appropriate key. 

Ciphers work with keys to encode or decode text. 

Ciphertext

Encoded text after a cipher has been applied to it.

Digital certificate

An electronic document that identifies and describes an organization that has 
been verified and signed by a trusted organization called a certificate 
authority. 

A digital certificate is similar in concept to an “identification card.” SSL uses 
certificates to authenticate servers.

For more information about digital certificates, see 

Digital signature

A checksum that verifies that a message was created by the stated author and 
was not altered since its creation.

Key

A numeric parameter used by a cipher to encode or decode text.

Plaintext or cleartext

Message text in its original form, before it gets encoded by a cipher.