Accounts & keys

Key type

Every BKC account is an ML-DSA-65 key pair (FIPS 204, security category 3).

	Bytes
Seed	32
Public key	1,952
Private key (expanded)	4,032
Signature	3,309

The chain accepts no other account key. secp256k1 and ed25519 signers are rejected by the ante handler (error code 1101); the node's keyring refuses to create them (unsupported signing algo); there is no Ledger support because no hardware wallet implements ML-DSA.

Funds sent to a pre-quantum address are lost

An address carries no key type. If you send BKC to an address derived from a secp256k1 key (for example an address copied from MetaMask), the chain accepts the transfer — and nothing can ever sign for that address.

Addresses

An address is the first 20 bytes of SHA-256(public key). It has two spellings:

Spelling	Example	Used by
bech32, prefix bkc	bkc1n8knf9x56r3dxc4rmvxd2u7tad82kcnwtsrqnm	Cosmos SDK, CLI, REST, wallets
hex (EIP-55)	0x99ED3494D4D0E2D362A3DB0CD573CBEB4EAB626E	EVM, Solidity, explorer

Both are the same account. Convert with the SDK:

import { toEvmAddress, toBech32Address } from "@bkc-network-lib/sdk";

toEvmAddress("bkc1n8knf9x56r3dxc4rmvxd2u7tad82kcnwtsrqnm"); // 0x99ED…626E (checksummed)
toBech32Address("0x99ED3494D4D0E2D362A3DB0CD573CBEB4EAB626E"); // bkc1n8kn…rqnm

or with the node binary: BKCd debug addr bkc1….

From a mnemonic to a key

BKC keeps BIP-39 mnemonics, but does not use BIP-32 derivation — BIP-32 is defined for elliptic curves. Instead:

bip39Seed = BIP39(mnemonic, passphrase)                       64 bytes
mldsaSeed = HKDF-SHA256(ikm  = bip39Seed,
                        salt = "BKC/ML-DSA-65",
                        info = "m/44'/118'/0'/0/0",            the HD path, as a string
                        len  = 32)
keypair   = ML-DSA-65.KeyGen(mldsaSeed)

Consequences worth knowing:

• The same mnemonic gives a different address on BKC than on any secp256k1 chain. That is expected.
• The HKDF salt is chain-specific. A wallet using another salt derives another account from the same words.
• m/44'/118'/0'/0/0 is the default path (coin type 118). Change the account or index and you get an independent key.
• Tools that take a seed (BKC_SEED in Hardhat, BkcSigner.fromSeed) want the 32-byte mldsaSeed, not a secp256k1 private key and not the 64-byte BIP-39 seed.

Creating an account

Hardhat

npx hardhat bkc-new-account
# prints a 32-byte seed and its bkc1… / 0x… addresses

SDK

import { DirectMldsa65HdWallet } from "@bkc-network-lib/sdk";

const wallet = await DirectMldsa65HdWallet.generate(24, { prefix: "bkc" });
const [account] = await wallet.getAccounts();
console.log(account.address, wallet.mnemonic);

Node CLI

BKCd keys add alice                    # --key-type defaults to mldsa65
BKCd keys add alice --recover          # from an existing mnemonic

An account exists on chain only after it first receives funds — get some from the faucet.

Sequence and nonce

A Cosmos account has a sequence that increases by one with every transaction it signs. Wrapped EVM calls use it as their nonce: call_nonce must equal the sequence the transaction is signed with. Contract accounts inside the EVM keep ordinary EVM nonces, which is why CREATE addresses come out exactly as Ethereum tooling predicts. See Transactions & EVM calls.