Security essentials
The principles, threats, cryptography, and Linux skills everything builds on.
Access control
Understand subjects, resources, permissions, and enforcement through a shared-drive example, including how access changes over time.
Adversary in the middle
An intermediary may observe or alter a communication path.
AES
A symmetric block cipher whose safe use depends on its mode and implementation.
Asymmetric cryptography
Explore public and private keys, encryption, signatures, and key agreement without confusing their different purposes.
Authentication
Understand how authentication verifies an account, how login sessions work, and why recovery and multifactor methods matter.
Authorization
Learn how applications check permission for individual resources and actions, with an invoice example and practical access tests.
Availability
Make the required service accessible to authorized users when it is needed.
Bell–LaPadula model
A formal model focused on confidentiality across classification levels.
Biba integrity model
Protect trusted information from less trustworthy inputs.
Botnets
A coordinated set of compromised systems can perform distributed activity.
Brute-force attacks
Try candidates until a valid secret or answer is found.
Caesar ciphers
A historical substitution demonstrates why simple secrecy schemes fail.
Careers in cybersecurity
Security includes technical, investigative, and business-focused work.
Chinese Wall model
Restrict access dynamically to manage conflicts of interest.
Clark–Wilson model
Protect business integrity through controlled transactions and separate duties.
Confidentiality
Limit information disclosure to the people and systems that should receive it.
Credential stuffing
Reused credentials can turn a breach elsewhere into access here.
Credentials from Password Stores
Password-store access targets credentials retained by operating systems or applications.
Cryptanalysis
Study weaknesses in cryptographic schemes and their use.
Cryptographic hashing
Explore cryptographic digests, file comparisons, collisions, and trusted reference values through an evidence-copy example.
Cryptographic randomness
Keys and unpredictable challenges depend on suitable random generation.
Cryptography
Understand encryption, hashing, and digital signatures through a software-update example, with clear guidance on keys and trust.
CrypTool
Explore cryptographic ideas through educational demonstrations.
CyberChef
Transform data with a clear understanding of the operation and sensitivity.
Defense in depth
Use complementary protections so one failure does not decide the outcome.
Denial of service
Exhaust or disrupt a service so legitimate users cannot use it.
Digital certificates and PKI
Bind a public key to an identity within a trust system.
Digital signatures
Learn what digital signatures verify, why trusted public keys matter, and what a valid signature cannot prove about software safety.
Drive-by downloads
Visiting or interacting with content can initiate unwanted download or execution paths.
ECB and block-cipher modes
A cipher needs a construction suited to the data and protection goal.
Elliptic-curve cryptography
Public-key operations using elliptic-curve mathematics.
Email validation and verification
Email validation checks whether an address meets the application's supported format, while verification checks control of the mailbox through an appropriate flow.
End-to-end encryption
Protect message content between the intended endpoints, while recognizing other exposure.
Exploitation for Credential Access
Exploitation for credential access uses a vulnerability to obtain authentication material.
Forced Authentication
Forced authentication induces a system to send authentication material to an unintended party.
Forge Web Credentials
Forged web credentials exploit a trust relationship used to create accepted authentication material.
Frequency analysis
Repeated patterns can reveal structure in classical ciphers.
Input Capture
Input capture observes user-entered information through software or deceptive interfaces.
Insider threats
Legitimate access can still be misused or cause harm.
Integrity
Keep information and actions consistent with authorized, trustworthy states.
IPsec
Protect IP traffic through negotiated security associations.
JSON Web Token (JWT) security
JWTs carry claims in a standardized token format.
JWT expiration and revocation
JWT revocation addresses how a service stops accepting a token before its nominal expiration.
Key agreement
Establish a shared secret without sending that secret as plain data.
Key management
Follow cryptographic keys from creation to retirement, including access, rotation, recovery, and the risks of deleting old keys.
Least privilege
Design access around necessary actions, resources, and duration, with examples of service permissions and temporary administration.
Legacy cryptography
Understand historical algorithms without treating them as current defaults.
Linux file permissions
Read, write, and execute rights apply differently to files and directories.
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