YanoSecCourse / Concepts
Concepts
One idea per entry: a one-line definition and the lessons that teach it.
19 short entries
- 01CIAConfidentiality, integrity and availability: limiting unauthorized disclosure, preventing improper changes, and keeping systems and data available when needed.
- 02PortA number from 0 to 65535 that, together with an IP address and a protocol such as TCP or UDP, identifies a network endpoint.
- 03DNS recordA typed piece of Domain Name System data. For example, an A record associates a domain name with an IPv4 address.
- 04CookieA name and value stored by a browser and sent on requests that match its rules. Servers can set cookies with the Set-Cookie response header.
- 05SessionA way for an application to recognize related requests, often through an identifier in a cookie. It can maintain a signed-in state.
- 06HashA fixed-length value, called a digest, computed from input. A cryptographic hash is designed to make recovering input from a digest impractical; guesses can still be tested.
- 07EncodingA reversible way to represent data, such as Base64 or hex. These formats need no secret key and do not provide confidentiality.
- 08EncryptionA transformation that uses a key to protect data from unauthorized reading. Its protection depends on the scheme, key handling and correct use.
- 09Same-origin policyBrowser restrictions on scripts accessing data from a different origin: scheme, host and port. Cross-origin resource sharing (CORS) can allow some reads; sending a request is a separate question.
- 10SUIDSet-user-ID: a permission bit that can give an eligible executable its file owner's effective user identity. System rules can prevent that change.
- 11SubnetA block of addresses that share a prefix, written as an address, a slash and a prefix length.
- 12TCP handshakeThe usual SYN, SYN-ACK, ACK exchange used to establish a TCP connection. These messages synchronize the two endpoints' connection state.
- 13Magic bytesA recognizable byte pattern, often at the start of a file, that suggests its format. A match is a clue, not proof that the whole file is valid.
- 14XORExclusive or: a bit is 1 when exactly one input bit is 1. Applying the same key twice gives the input back.
- 15RSAA public-key construction with related public and private keys. The lesson uses tiny prime numbers to explain the arithmetic; real encryption and signatures need secure schemes and suitable keys.
- 16Domain controllerA server that holds directory data for a Windows domain and helps authenticate domain accounts. A domain can have several controllers.
- 17FlagThe answer string submitted for a capture-the-flag challenge. Acceptance shows that the string matches the challenge's expected answer; your notes explain how you found it.
- 18WriteupA written account of a challenge's evidence, steps and reasoning. Share it only when the event's rules allow publication.
- 19ScopeThe written limits of permission: which targets, which actions, and when.