Crypto has its own vocabulary, and a lot of it is jargon dressed up to sound complicated. This glossary explains the terms you will meet inside B28 in plain language, with a note on why each one matters and where it can bite you. B28 is a non-custodial wallet: your keys and recovery phrase live on your own device, we never hold or control your funds, and on-chain transactions are final and cannot be reversed.
The essentials
Non-custodial
A wallet where you, and only you, hold the keys to your money. B28 is non-custodial. We never hold, control, or access your funds, and we cannot move them for you. The upside is full ownership. The responsibility is that securing your recovery phrase is down to you, and if you lose it, no one can restore your access.
Custodial
The opposite of non-custodial. A custodial service holds your funds and keys on your behalf, the way an exchange or a traditional app might. They can freeze, move, or recover the account, which is convenient until it is not. B28 is not custodial: we do not hold your funds and cannot freeze or reverse anything.
Self-custody
The practice of holding your own crypto with your own keys, rather than trusting a company to hold it for you. Self-custody is the model B28 is built on. You are your own bank, which means both the control and the safekeeping sit with you.
Private key
The secret code that controls your crypto. Anyone who has your private key can move your funds. In B28 your keys are generated and stored on your device, behind your device biometrics, and never leave it. We never see them. Never share a private key with anyone, including anyone claiming to be B28 support.
Public key
The counterpart to your private key. It can be shared safely and is used to derive your wallet address so people can send you crypto. Sharing a public key or address does not let anyone spend your funds. Sharing a private key does.
Recovery phrase (seed phrase)
A list of 12 to 24 ordinary words that is the master key to your entire wallet. Whoever holds your recovery phrase can recreate your wallet and take everything in it. B28 does not store it and cannot recover it for you. Write it down, keep it offline, and never type it into a website, a message, or a support chat. Storing it as a photo, a note, or a file in the cloud increases the risk that it is stolen.
Mnemonic / BIP-39
The technical name for a recovery phrase. BIP-39 is the widely used standard that turns a string of random data into a memorable list of words drawn from a fixed wordlist. When people say mnemonic, seed phrase, or recovery phrase, they usually mean the same thing.
Wallet address
The string of letters and numbers you share to receive crypto, similar in spirit to an account number. Each network has its own address format. Always double-check the address before you send, character by character, because a transaction sent to the wrong address cannot be reversed.
Biometrics
Your fingerprint or face used to unlock your device and authorise actions in B28. The biometric check happens on your device using its built-in security and is never sent to us. It is what protects your keys from anyone who picks up your phone.
How blockchains work
Blockchain
A shared, public record of transactions maintained by a network of computers rather than a single company. Once something is recorded, it is extremely hard to change, which is what makes crypto transactions final. B28 does not operate any blockchain and cannot approve, alter, or reverse what happens on them.
On-chain
Anything that has been recorded on the blockchain itself, such as a confirmed send. On-chain activity is public and permanent. B28 cannot cancel, edit, or undo an on-chain transaction once it is submitted.
Network (L1)
A Layer 1, or L1, is a base blockchain that settles its own transactions, such as Bitcoin, Ethereum, or Solana. B28 supports 16 networks. Each network is separate, so sending an asset on the wrong network can mean it does not arrive.
Layer 2 (L2)
A network built on top of a Layer 1 to make transactions faster and cheaper while still relying on the base chain for security. Arbitrum, Optimism, Base, and Polygon are examples B28 supports. The same token can exist on several networks, so always confirm you are on the right one.
Gas / network fee
The fee paid to the network to process your transaction. It goes to the network, not to B28, and the amount changes with how busy the network is. If you do not have enough of the network's native coin to cover gas, the transaction will not go through. B28 does not control or set these fees.
Token
An asset that lives on top of an existing blockchain rather than being the network's own native coin. Most stablecoins are tokens. The same token can appear on multiple networks under the same name, which is why checking the network matters.
Stablecoins and converting
Stablecoin
A crypto token designed to track the value of a regular currency, usually the US dollar, so its price stays roughly steady. Stablecoins are not risk-free and are not insured. The issuer and the network both carry risk, and no stablecoin is guaranteed to hold its value.
USDC
A widely used US-dollar stablecoin. B28 supports USDC on several networks. The same name on a different network is a different token, so confirm the network before sending or receiving.
USDT
Another widely used US-dollar stablecoin, sometimes called Tether. As with USDC, the network matters, and decimals and contract details differ between networks.
Swap / convert
Exchanging one crypto asset for another, for example converting one token into a stablecoin. In B28 the in-app convert feature shows a live-rate preview and is rolling out. The swap itself is carried out through a third-party provider, and you authorise it yourself with biometrics. B28 does not execute trades on your behalf or give investment advice.
On-ramp
Buying crypto with regular money, such as a card payment. B28's buy-with-card flow uses a third-party on-ramp partner. Any identity checks and fees on that step are handled by the partner under their own terms, not by B28.
Off-ramp
The reverse of an on-ramp: turning crypto back into regular money. Where this is offered, it runs through a third-party partner rather than B28 itself.
Mid-market rate
The midpoint between the buy and sell price of a currency pair, often treated as the fair reference rate. Real conversions usually differ from it once fees and spread are included, so a quoted rate and the mid-market rate are not the same thing.
Spread
The gap between the price to buy and the price to sell an asset. A wider spread means a worse effective rate. When comparing convert options, the spread matters as much as any headline fee.
Slippage
The difference between the price you saw when you started a swap and the price you actually get when it settles, because the market can move in those seconds. Larger trades and less liquid tokens tend to have more slippage. A live-rate preview is an estimate, not a locked-in guarantee.
Staying safe
Sentinel (B28's scam-shield)
B28's built-in safety layer. Before you sign, Sentinel screens addresses and tokens for known scam patterns, such as look-alike addresses, honeypot tokens, and risky approvals, and warns you. It is a safety aid, not a guarantee. You still sign every transaction yourself, and you remain responsible for what you approve.
Address poisoning
A scam where an attacker sends you a tiny transaction from an address crafted to look almost identical to one you use, hoping you later copy it from your history and send funds to them by mistake. Always verify the full address, not just the first and last few characters. Sentinel helps flag look-alike addresses.
Honeypot
A token designed so you can buy it but cannot sell it, trapping your money. The price may look like it is rising while you are quietly unable to exit. Sentinel screens for honeypot patterns and warns you before you interact.
Drainer / malicious approval
A scam where a website or token asks you to approve a permission that, once signed, lets an attacker pull tokens out of your wallet. The dangerous step is signing the approval, not visiting the site. Read what you are approving, and heed Sentinel's warnings before you sign.
Seed-phrase phishing
Any attempt to trick you into revealing your recovery phrase or private key, through fake support agents, fake apps, fake giveaways, or fake security checks. There is no legitimate reason to enter your recovery phrase anywhere except when restoring your own wallet. B28 and its partners will never ask for it.
Hot wallet
A wallet on an internet-connected device, such as a phone. It is convenient for everyday use but more exposed than an offline option. B28 is a hot wallet, which is why device security and biometrics matter.
Cold wallet
A wallet kept offline, such as a dedicated hardware device, used to reduce exposure for funds you do not move often. Cold storage trades convenience for a smaller online attack surface.
Identity, access, and other terms
KYC (Know Your Customer)
Identity checks that some regulated services require. The B28 non-custodial wallet itself does not require KYC to hold, send, or receive. Where identity checks apply, such as a third-party on-ramp or the coming card, they are run by that partner under their own terms, and B28 does not retain that data.
Sanctions screening
Blocking access from certain countries and restricted parties to comply with sanctions law. B28 applies a server-side geoblock for Cuba, Iran, North Korea, Syria, Russia, and Belarus.
ENS (Ethereum Name Service)
A human-readable name that maps to a wallet address on Ethereum, so a memorable name can stand in for a long string of characters. It can make sending easier, but you should still confirm the underlying address resolves to who you expect.
Smart contract
Self-executing code stored on a blockchain that runs automatically when its conditions are met. Tokens, swaps, and approvals all involve smart contracts. They are only as safe as their code, which is why screening and reading approvals before signing matters.
Irreversibility
The fact that once a transaction is confirmed on-chain, it is final. It cannot be cancelled, reversed, refunded, or frozen by anyone, including B28. This is why checking the address, network, and amount before you send is so important.
Volatility
How sharply a crypto asset's price can move, sometimes a lot in a short time. Crypto is volatile and uninsured, and you can lose money. Nothing in B28 is financial or investment advice.
The card (coming)
B28 has described an instant-convert card for spending. It is coming, not live. Any reference to a card in B28 today describes a planned feature, not a service you can use yet. We have committed to publishing an independent security review before the card launches.
A note on advice
This glossary explains terms in plain language. It is not financial, investment, legal, or tax advice. B28 provides technology, not recommendations. You control your keys, you sign every transaction yourself, and you are responsible for the decisions you make. If you are unsure, take your time and verify before you act.