Software Encryption Methods Quiz

12 Questions

What is the primary purpose of a Hardware Security Module (HSM) mentioned in the text?

Accelerating symmetric and asymmetric encryption

Which technology is associated with verifying a sender's identity to the receiver?

Digital Certificate

What function does Public Key Infrastructure (PKI) serve according to the text?

Managing public keys in digital certificates

Which protocol is considered somewhat obsolete and used mostly for web servers and browsers?

Secure Sockets Layer (SSL)

What is the main purpose of Secure/Multipurpose Internet Mail Extensions (S/MIME) mentioned in the text?

Encrypting email communication

What is the primary function of Bastille as mentioned in the text?

Proactively configuring an operating system for increased security

Which type of Intrusion Detection System relies more on baselines than signatures?

Anomaly-based IDS

What is the main focus of Nessus and OpenVAS as mentioned in the text?

Conducting vulnerability scanning from a remote host

Which type of IDS uses rules or patterns of known malicious traffic to detect threats?

Signature-based IDS

What is the essential role of penetration testers as mentioned in the text?

Discover security weaknesses that may lead to system compromise

Which aspect is considered crucial for good Linux security according to the text?

Detecting malicious activity

What distinguishes Anomaly-based IDS from Signature-based IDS?

'Anomaly-based IDS uses baselines, while Signature-based IDS relies on patterns of known malicious traffic.

Study Notes

Hash Algorithms

Common hash algorithms include MD5, SHA, RIPEMD, and HMAC

Symmetric Cryptographic Algorithms

Use the same single key to encrypt and decrypt data
Common symmetric cryptographic algorithms include DES, 3DES, AES, RC, IDEA, Blowfish, and Twofish

Asymmetric Cryptographic Algorithms (Public Key Cryptography)

Use two keys (key pairs): public key and private key
Public key is known to everyone and can be freely distributed
Private key is known only to the individual to whom it belongs
Common asymmetric cryptographic algorithms include RSA, ECC, and DSA

Cryptography Basics

Cryptography: scrambling information so that only authorized individuals can use it
Encryption: process of changing original data into scrambled data
Decryption: process of changing scrambled data back to its original state
Plaintext: unencrypted data that is the input for encryption or the output of decryption
Ciphertext: scrambled and unusable output of encryption
Cleartext: usable (unencrypted) data that is transmitted or stored and is not intended to be encrypted
Cipher (or Algorithm): procedures based on a mathematical formula to encrypt and decrypt the data
Key: mathematical value entered into a cipher to produce the ciphertext
Cryptoanalysis: sophisticated statistical analysis on ciphertext to try to discover the underlying key to the cryptographic algorithm

Steganography

Hiding the existence of data
Divides data into smaller pieces and hides them in unused portions of a file

Implementing Encryption

Through software: Microsoft’s EFS (Encrypting File System), Apple’s FileVault, and PGP (Pretty Good Privacy)
Through hardware: USB Device Encryption, Self-Encrypting Drives (SEDs), and Trusted Platform Module (TPM)

Network Security

Firewalls provide an essential layer of security
All network services require a port number to communicate
IANA (Internet Assigned Numbers Authority) contains a list of port numbers and their uses
System Ports (0 to 1023): well-known ports used by system processes
User Ports (1024 to 49,151): registered ports assigned by IANA for specific service
Dynamic and/or Private Ports (49,152 to 65,535): used for private or customized services
Linux systems use a Packet-Filtering Firewall system
Netfilter is integrated into all Linux kernels and offers packet filtering, network address translation, and port translation
Front-ends for netfilter’s firewall functionality include iptables, firewalld, and UFW (Uncomplicated Firewall)

Firewall Configuration

iptables: standard firewall included in most Linux distributions
firewalld: updated version of iptables, used in Red Hat based distributions
UFW (Uncomplicated Firewall): simpler to use than iptables
Zones in firewalld: block, public, and private network zones

Encrypting Partitions and Volumes

Usually done when Linux is installed through kernel-space tools
dm_crypt: the most common Linux kernel module that handles encryption at the kernel level
LUKS (Linux Unified Key Setup): command line front-end for dm_crypt

Encrypting Files and Directories

Used after Linux is installed through user-space tools
PGP (Pretty Good Privacy): common command line tool for encrypting files and directories
GPG (GNU Privacy Guard or GnuPG): implementation of OpenPGP for encrypting files and folders
GnuPG Shell and GPA (GNU Privacy Assistant): GUI front-ends for GPG