CIA Part 3 cheat sheet

Break-even units = fixed costs ÷ contribution margin per unit; break-even sales dollars = fixed costs ÷ contribution margin ratio.

Contribution margin = sales − all variable costs; it covers fixed costs first, and any remainder is operating income.

Relevant costs are future costs that differ among alternatives; exclude sunk costs and unavoidable allocated fixed costs, but include opportunity cost.

Predetermined overhead rate = estimated overhead ÷ estimated allocation base; actual overhead exceeding overhead applied means overhead is underapplied.

Materials price variance = (actual price − standard price) × actual quantity purchased; materials quantity variance = (actual quantity used − standard quantity allowed) × standard price.

Minimum transfer price = variable cost per unit + opportunity cost per unit of the transferred item; this preserves goal congruence when capacity is constrained.

Six Sigma uses DMAIC (define, measure, analyze, improve, control); TQM pursues continuous incremental improvement, while business process reengineering seeks radical redesign.

Maslow's hierarchy: physiological, safety, social, esteem, self-actualization; lower-level needs must be substantially satisfied before higher needs motivate.

Herzberg: hygiene factors (pay, policy, conditions) prevent dissatisfaction but do not motivate; motivators (achievement, recognition, responsibility, growth) drive satisfaction.

CIA triad: confidentiality via encryption and access control, integrity via hashing and reconciliation, availability via redundancy, backups, and DDoS protection.

Access control models: DAC (owner grants access), MAC (labels and clearance), RBAC (roles), ABAC (attributes); least privilege and need-to-know apply to all.

Authentication factors are knowledge (password), possession (token), inherence (biometric); MFA requires factors drawn from two or more different categories.

Symmetric encryption (AES) is fast for bulk data but has a key-distribution problem; asymmetric encryption (RSA, ECC) solves key exchange and enables signatures but is slow.

A digital signature is a message hash encrypted with the sender's private key; it gives integrity, authentication, and non-repudiation, but not confidentiality.

Hashing is one-way and collision-resistant; salting a password before hashing defeats precomputed rainbow tables; hashes detect alteration but do not conceal data.

Control types: preventive (firewall, encryption), detective (IDS, log review, reconciliation), corrective (restore, patch); defense in depth layers independent controls.

NIST Cybersecurity Framework functions: identify, protect, detect, respond, recover; ISO/IEC 27001 specifies ISMS requirements while 27002 provides control guidance.

Business continuity metrics: RTO is maximum tolerable downtime, RPO is maximum tolerable data loss; a hot site is near-immediate, a cold site provides space only.

OSI layers 1–7: physical, data link, network, transport, session, presentation, application; a switch operates at layer 2, a router at layer 3.

RAID 0 is striping with no redundancy; RAID 1 mirrors; RAID 5 stripes with distributed parity, usable capacity of n−1 disks, and tolerates one disk failure; RAID 6 tolerates two; RAID 10 combines mirroring and striping.

Cloud service models: IaaS (customer manages OS and above), PaaS (customer manages applications only), SaaS (provider manages everything); deployment models are public, private, hybrid, and community.

ITIL: incident management restores service quickly; problem management identifies root cause; change management assesses risk and authorizes changes; an SLA documents agreed service levels.

SDLC phases: planning, analysis, design, build, test, implement, maintain; agile delivers iterative increments; DevOps automates build, test, and deployment through CI/CD pipelines.

Database rules: ACID means atomicity, consistency, isolation, durability; normalization reduces redundancy and update anomalies; OLTP handles transactions while OLAP handles analytical queries.

Backup types: full (all data), incremental (changes since the last backup of any type), differential (changes since the last full); restoring incremental backups requires the last full plus every increment.

Virtualization: a Type 1 hypervisor runs on bare metal, a Type 2 hypervisor runs on a host OS; containers share the host kernel and are lighter than virtual machines.

Batch processing groups transactions for scheduled runs; online real-time processing updates immediately; RPA uses software bots to automate rule-based repetitive tasks.

Accounting equation: assets = liabilities + equity; every transaction preserves the balance under double-entry bookkeeping.

Liquidity: current ratio = current assets ÷ current liabilities; quick ratio = (cash + marketable securities + receivables) ÷ current liabilities.

DuPont: ROE = net profit margin × total asset turnover × equity multiplier, where equity multiplier = total assets ÷ total equity.

Efficiency: inventory turnover = COGS ÷ average inventory; days sales outstanding = (accounts receivable ÷ credit sales) × 365.

Leverage: debt ratio = total liabilities ÷ total assets; debt-to-equity = total debt ÷ equity; times interest earned = EBIT ÷ interest expense.

Capital budgeting: NPV = present value of inflows − initial outlay (accept if positive); IRR is the rate where NPV = 0 (accept if above cost of capital); profitability index = PV of inflows ÷ initial outlay.

WACC = (weight of debt × after-tax cost of debt) + (weight of equity × cost of equity); CAPM: cost of equity = risk-free rate + beta × (market return − risk-free rate).

Time value: PV = FV ÷ (1 + r)^n; present value of an ordinary annuity = PMT × [(1 − (1 + r)^−n) ÷ r].

Bonds sell at a premium when the coupon rate exceeds the market yield, at a discount when the coupon rate is lower, and at par when the two are equal.