Cryptocurrency Cheat Sheet 2026

The 30 highest-yield Cryptocurrency facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the function of 'Chainlink VRF' in smart contract development? → It validates that randomness used in a contract is provably fair and tamper-resistant
2. What is a 'sidechain' in blockchain architecture? → A separate blockchain that runs in parallel and is pegged to a main chain
3. What was the name of the well-known Japanese Bitcoin exchange that went bankrupt in 2014? → Mt. Gox
4. What risk does address reuse introduce in a cryptocurrency wallet? → Reduced privacy by linking transactions to one identity
5. What is the 'difficulty target' in Bitcoin mining, and how does hashing relate to it? → A threshold the block's SHA-256 hash must be numerically below to be accepted
6. Which of the following best describes the Diffie-Hellman key exchange? → Two parties derive a shared secret over a public channel without transmitting it directly
7. What is 'yield farming' in DeFi? → Lending or staking crypto assets to earn rewards or interest
8. Under the Travel Rule, what information must U.S. crypto businesses transmit when transferring funds over $3,000? → Sender and receiver identifying information
9. What is 'FOMO' and how does it typically affect crypto markets? → Fear Of Missing Out; it drives emotional buying during rallies, often inflating bubbles
10. What is the primary purpose of a crypto exchange's AML compliance program? → To detect, prevent, and report money laundering and terrorist financing
11. Which of the following best describes a 'smart contract'? → Self-executing code stored on a blockchain that runs when predefined conditions are met
12. What does the acronym 'dApp' stand for? → Decentralized Application
13. What does 'KYC' stand for in the context of cryptocurrency exchanges? → Know Your Customer
14. What is the 'Travel Rule' in the context of cryptocurrency compliance? → A requirement to transmit sender/receiver information for transfers above $3,000
15. What is the significance of 'support' and 'resistance' levels in crypto charting? → Historical price zones where buying or selling pressure has previously concentrated
16. What is 'impermanent loss' in DeFi? → A temporary loss experienced by liquidity providers when token prices diverge
17. What is a '51% attack' on a Proof-of-Work blockchain? → When a single entity controls the majority of hash rate and can rewrite recent history
18. What vulnerability is introduced when the same private key is used to sign two different messages with the same nonce in ECDSA? → The private key can be algebraically recovered from the two signatures
19. On the CoinDesk Bitcoin Price Index, what was the highest Bitcoin price ever? → $1,165
20. A BIP39 seed phrase typically consists of how many words? → 12 or 24
21. Which US regulatory framework requires cryptocurrency exchanges to implement AML and KYC programs? → Bank Secrecy Act
22. What is the risk of reusing Bitcoin addresses? → It can reduce privacy and potentially weaken cryptographic security over time
23. What is a 'seed phrase' (or recovery phrase) in crypto? → A series of words that can restore access to a crypto wallet
24. What is a flash loan in DeFi? → An uncollateralized loan that must be borrowed and repaid within a single transaction
25. What is the significance of using a cryptographically secure pseudo-random number generator (CSPRNG) in wallets? → It ensures private keys are generated with sufficient entropy and cannot be predicted
26. What is a 'stablecoin'? → A crypto asset designed to maintain a stable value, often pegged to a fiat currency
27. In Solidity, what does the 'view' function modifier indicate? → The function reads state but does not modify it
28. What is 'block finality' in blockchain systems? → The point at which a block is considered irreversible
29. What is the 'nothing-at-stake' problem in early proof-of-stake designs? → Validators could vote on multiple competing forks at no cost, undermining consensus
30. Which regulation requires U.S. taxpayers to report cryptocurrency transactions to the IRS? → Internal Revenue Code Section 6050I