NKN Wallet JSON Format (v2)

Wallet is encrypted by user specified password and stored in JSON format:

{
    "Version": <integer>,
    "IV": <string>,
    "MasterKey": <string>,
    "SeedEncrypted": <string>,
    "Address": <string>,
    "Scrypt": {
        "Salt": <string>,
        "N": <integer>,
        "R": <integer>,
        "P": <integer>,
    },
}

• Version the verison of this wallet.
• IV Initialization Vector of AES-CBC encryption algorithm, encoded as hex string.
• MasterKey a key encrypted by passwordkey. It's used to encrypt Ed25519 secret seed, encoded as hex string.
• SeedEncrypted the Ed25519 secret seed encrypted by unencrypted MasterKey. It's used to sign the transactions, encoded as hex string.
• Address NKN address of this wallet, encoded in base58. Wallet address always starts with letter "NKN".
• Scrypt scrypt parameters used to derive key from password.

Wallet creating algorithm

Input: password, seed
Output: wallet.json
1. PasswordKey <- scrypt(password, salt, N, r, p, keyLen=32)
2. MasterKeyUnencrypted <- random_bytes(32)
3. IV <- random_bytes(16)
4. MasterKey <- aes_cbc_enc256(MasterKeyUnencrypted, PasswordKey, IV)
5. SeedEncrypted <- aes_cbc_enc256(seed, MasterKeyUnencrypted, IV)
6. PublicKey <- ed25519_pubkey_from_seed(seed)
7. SignatureScript <- {0x20||publickey||0xAC}
8. ProgramHash <- ripemd160(sha256(SignatureScript))
9. Address <-base58check_encode(0x02b825||ProgramHash||sha256(sha256(0x02b825||ProgramHash))[0:4])
10. Version <- 2
11. Save {Version, IV, MasterKey, SeedEncrypted, Address, Scrypt} to wallet.json

Terms and definitions

• sha256(msg) SHA-256 cryptographic hash algorithm.
• random_bytes(len) random bytes with size len.
• aes_cbc_enc256(data, key, iv) AES-256-CBC encryption algorithm.
• ed25519_pubkey_from_seed(seed) Derive Ed25519 public key from seed.
• ripemd160(msg) RIPEMD-160 cryptographic hash algorithm.
• base58check_encode(msg) Base58Check encoding algorithm.
• scrypt(password, salt, N, r, p, keyLen) Scrypt key derivation function.

Reference Implementation

https://github.com/nknorg/nkn/tree/master/vault