BTA CBSP key terms

A one-way mathematical function that converts any input into a fixed-length fingerprint. Changing even one character produces a completely different output, so it is used to detect tampering and link blocks.

A system using a matched key pair: a public key that others may see and a private key kept secret. It supports digital signatures and secure key exchange without sharing secrets beforehand.

Cryptographic proof created with a private key that anyone holding the matching public key can verify. It demonstrates authenticity and integrity of a transaction and supports non-repudiation.

The controls and procedures used to generate, store, back up, and restrict access to signing keys. Weak custody lets an attacker sign transactions as the owner, so it is a primary security concern.

A tamper-resistant device that generates and stores cryptographic keys and performs signing inside its boundary. Keys typically never leave the device in plaintext, reducing exposure to malware on general-purpose systems.

A scripted, witnessed procedure for generating and distributing cryptographic keys, with defined roles and recorded evidence. It reduces the risk of insider tampering during the most sensitive moment of a system's life.

A tree of hashes in which each parent summarizes its children, ending in a single root hash. It allows efficient proof that a transaction is included without revealing the entire dataset.

The single top hash of a Merkle tree, stored in the block header. Any change to a transaction alters the root, so it binds all transactions in a block to that header.

The metadata portion of a block, containing fields such as the previous block hash, Merkle root, timestamp, and a difficulty or consensus value. It is the compact data that nodes hash and compare.

The first block in a blockchain, hard-coded or agreed upon as the starting point of the chain. Every later block traces ancestry back to it, anchoring the ledger's history.

The protocol rule set by which distributed nodes agree on the next valid block and the canonical chain. Examples include proof of work and proof of stake, each with distinct attack and failure models.

A divergence in the blockchain where two or more competing versions of history exist. Soft forks tighten rules compatibly; hard forks change rules and can permanently split the network and its assets.

Replacement of one set of recent blocks by a longer or heavier competing chain. Deep reorganizations can reverse confirmed transactions, which matters for settlement assurance and exchange crediting policies.

An attack in which an entity controlling a majority of mining or staking power can exclude transactions and rewrite recent history. It generally cannot steal existing coins or forge signatures.

Program code deployed to a blockchain that executes automatically when invoked. Because deployed code is often immutable and handles value, flaws become permanently exploitable and are a major risk source.

A flaw where a contract calls an external address before updating its own state, letting the callee call back and repeat withdrawals. It is mitigated by checks-effects-interactions ordering and reentrancy guards.

A condition where an arithmetic result exceeds the storage range of a numeric type and wraps to an unexpected value. In token contracts it can mint or transfer incorrect balances unless checked arithmetic is used.

Attacking a contract by distorting the external data feed it trusts, often through a thin market price. Defenses include time-weighted averages and multiple independent sources.

An exploit using uncollateralized borrowed funds within a single transaction to manipulate prices or governance, then repay the loan. Because no capital is at risk, it lowers the barrier to large-scale manipulation.

The ability to alter a transaction's identifier without invalidating its signature. It can confuse systems that track payments by transaction ID and was addressed by segregated witness and related changes.

Reusing a valid signed message or transaction in a different context where it is still accepted, such as across forked chains. Defenses include chain identifiers and nonces bound into the signature.

A value used once to make each message or transaction unique. In accounts it prevents replay and orders transactions; in proof of work it is the variable miners adjust to find a valid block hash.

A consensus approach requiring participants to expend computational effort to produce a block hash below a target. Security derives from the cost of out-powering honest participants rather than from identity.

A consensus approach where validators lock economic value and are chosen to propose or attest blocks, with penalties for misbehavior. Security depends on the cost of acquiring stake and slashing conditions.

Creating many fake identities to gain disproportionate influence over a peer-to-peer network or vote. Proof-of-work and proof-of-stake resist it by tying influence to costly resources rather than identity count.

Isolating a node by monopolizing all its peer connections, so it sees only an attacker-controlled view of the network. The victim may accept false transactions or be tricked about the current chain tip.

Configuring a blockchain node to reduce attack surface, including restricted remote interfaces, firewalling, least-privilege accounts, and authenticated peer connections. It limits exposure to remote exploitation and unauthorized RPC use.

Leaving a node's management interface reachable by untrusted parties. Unauthenticated RPC access can allow fund movement, node shutdown, or information disclosure, so interfaces should bind locally and require authentication.

Software or hardware that manages keys and constructs transactions on a user's behalf. It does not hold coins; it holds the ability to authorize transfers, making wallet security equivalent to key security.

A wallet whose signing keys reside on an internet-connected system for convenience. It suits small operational balances but increases exposure to malware, phishing, and remote compromise.

Keeping signing keys offline on dedicated hardware or paper so no network path reaches them. Transactions are signed offline and broadcast separately, greatly reducing remote theft risk.

A control requiring several distinct keys to authorize a transaction, often expressed as m-of-n. It removes single points of key compromise and supports separation of duties in treasury operations.

Deceiving a user into revealing credentials or signing a malicious transaction through impersonation or lookalike sites. In blockchain contexts a single signed approval can irreversibly drain assets.

Manipulating people through trust, urgency, or authority to bypass technical controls. Attackers often target help desks and employees to obtain credentials or influence key holders.

The property that recorded data cannot be altered without detection or network-wide agreement. It is probabilistic rather than absolute, since deep reorganizations are theoretically possible and off-chain data is unaffected.

The classic triad of security objectives. Blockchain design strongly emphasizes integrity and availability, while confidentiality is often weak because ledger data is replicated and public by default.

A cryptographic method proving a statement is true without revealing the underlying data. It supports privacy-preserving transactions and selective disclosure while preserving verifiability on a public ledger.

A documented set of roles, escalation paths, and procedures for detecting, containing, eradicating, and recovering from security incidents. Blockchain incidents require added steps such as key rotation and on-chain monitoring.

The disciplined collection and analysis of evidence from systems and ledgers to reconstruct what happened. On-chain analysis can trace fund flows, while off-chain logs establish how keys or hosts were compromised.

Identity verification and risk screening of customers before and during a business relationship. It supports anti-money-laundering obligations and helps firms avoid servicing sanctioned or fraudulent actors.

A regulatory requirement that virtual asset service providers exchange originator and beneficiary information for qualifying transfers. It creates data-sharing and privacy obligations across counterparties in a transaction chain.

Integrating security activities such as threat modeling, code review, and testing into each phase of software delivery. For smart contracts it includes formal review and staged deployment before handling real value.

A structured exercise identifying assets, adversaries, and plausible attack paths early in design. It directs limited security effort toward the most consequential weaknesses before code is written.