Perl

BIP39 Compute Binary Seed from Mnemonic

See more Encryption Examples

Creates a binary seed from a mnemonic. Uses the PBKDF2 function with a mnemonic sentence (in UTF-8 NFKD) used as the password and the string "mnemonic" + passphrase (again in UTF-8 NFKD) used as the salt. The iteration count is set to 2048 and HMAC-SHA512 is used as the pseudo-random function. The length of the derived key is 512 bits (= 64 bytes). Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

my $crypt = Chilkat2::Crypt2->new;

# Test with the test vectors at https://github.com/trezor/python-mnemonic/blob/master/vectors.json

# This is the 2nd test vector..
my $mnemonic = 'legal winner thank year wave sausage worth useful legal winner thank yellow';
my $passphrase = 'TREZOR';
my $expectedSeed = '2e8905819b8723fe2c1d161860e5ee1830318dbf49a83bd451cfb8440c28bd6fa457fe1296106559a3c80937a1c1069be3a3a5bd381ee6260e8d9739fce1f607';
my $expectedMasterKey = 'xprv9s21ZrQH143K2gA81bYFHqU68xz1cX2APaSq5tt6MFSLeXnCKV1RVUJt9FWNTbrrryem4ZckN8k4Ls1H6nwdvDTvnV7zEXs2HgPezuVccsq';

# The mnemonic sentence (in UTF-8 NFKD) used as the password.
# The string "mnemonic" + passphrase (again in UTF-8 NFKD) used as the salt.
# The iteration count is set to 2048 and HMAC-SHA512 is used as the pseudo-random function.
# The length of the derived key is 512 bits (= 64 bytes).

# We want the computed seed to be lowercase hex, therefore our salt must also be hex.
# The seed is the keyword "mnemonic" + passphrase (in this case is "TREZOR") converted to hex.
my $bdSalt = Chilkat2::BinData->new;
$bdSalt->AppendString('mnemonic', 'utf-8');
$bdSalt->AppendString($passphrase, 'utf-8');

my $computedSeed = $crypt->Pbkdf2($mnemonic, 'utf-8', 'sha512', $bdSalt->GetEncoded('hex_lower'), 2048, 512, 'hex_lower');

print 'Expected: ', $expectedSeed, "\n";
print 'Computed: ', $computedSeed, "\n";

# To compute the hd_master_key, duplicate this Python code:

#     def to_hd_master_key(seed: bytes, testnet: bool = False) -> str:
#         if len(seed) != 64:
#             raise ValueError("Provided seed should have length of 64")
#
#         # Compute HMAC-SHA512 of seed
#         seed = hmac.new(b"Bitcoin seed", seed, digestmod=hashlib.sha512).digest()
#
#         # Serialization format can be found at: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#Serialization_format
#         xprv = b"\x04\x88\xad\xe4"  # Version for private mainnet
#         if testnet:
#             xprv = b"\x04\x35\x83\x94"  # Version for private testnet
#         xprv += b"\x00" * 9  # Depth, parent fingerprint, and child number
#         xprv += seed[32:]  # Chain code
#         xprv += b"\x00" + seed[:32]  # Master key
#
#         # Double hash using SHA256
#         hashed_xprv = hashlib.sha256(xprv).digest()
#         hashed_xprv = hashlib.sha256(hashed_xprv).digest()
#
#         # Append 4 bytes of checksum
#         xprv += hashed_xprv[:4]
#
#         # Return base58
#         return b58encode(xprv)

# First compute the HMAC-SHA512 of the computedSeed
my $bdSeed = Chilkat2::BinData->new;
$bdSeed->AppendEncoded($computedSeed, 'hex_lower');
$crypt->EncodingMode('hex_lower');
$crypt->HashAlgorithm('sha512');
$crypt->SetMacKeyString('Bitcoin seed');
my $hmacSha512_hex = $crypt->MacBdENC($bdSeed);

my $bdHmac = Chilkat2::BinData->new;
$bdHmac->AppendEncoded($hmacSha512_hex, 'hex_lower');

my $bdXprv = Chilkat2::BinData->new;
$bdXprv->AppendEncoded('0488ade4', 'hex_lower');
$bdXprv->AppendEncoded('000000000000000000', 'hex_lower');
$bdXprv->AppendEncoded($bdHmac->GetEncodedChunk(32, 32, 'hex_lower'), 'hex_lower');
$bdXprv->AppendByte(0);
$bdXprv->AppendEncoded($bdHmac->GetEncodedChunk(0, 32, 'hex_lower'), 'hex_lower');

# Double hash using SHA256
$crypt->EncodingMode('hex_lower');
$crypt->HashAlgorithm('sha256');

my $bdHash = Chilkat2::BinData->new;
$bdHash->AppendEncoded($crypt->HashBdENC($bdXprv), 'hex_lower');
my $secondHash = $crypt->HashBdENC($bdHash);
$bdHash->Clear();
$bdHash->AppendEncoded($secondHash, 'hex_lower');

# Append the 1st 4 bytes of the bdHash to bdXprv.
$bdXprv->AppendEncoded($bdHash->GetEncodedChunk(0, 4, 'hex_lower'), 'hex_lower');

# Base58 encode bdXprv
my $computedMasterKey = $bdXprv->GetEncoded('base58');

print 'Expected Master Key: ', $expectedMasterKey, "\n";
print 'Computed Master Key: ', $computedMasterKey, "\n";