(AutoIt) BIP39 Compute Binary Seed from Mnemonic

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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).

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

$oCrypt = ObjCreate("Chilkat.Crypt2")

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

; This is the 2nd test vector..
Local $sMnemonic = "legal winner thank year wave sausage worth useful legal winner thank yellow"
Local $sPassphrase = "TREZOR"
Local $sExpectedSeed = "2e8905819b8723fe2c1d161860e5ee1830318dbf49a83bd451cfb8440c28bd6fa457fe1296106559a3c80937a1c1069be3a3a5bd381ee6260e8d9739fce1f607"
Local $sExpectedMasterKey = "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.
$oBdSalt = ObjCreate("Chilkat.BinData")
$oBdSalt.AppendString("mnemonic","utf-8")
$oBdSalt.AppendString($sPassphrase,"utf-8")

Local $sComputedSeed = $oCrypt.Pbkdf2($sMnemonic,"utf-8","sha512",$oBdSalt.GetEncoded("hex_lower"),2048,512,"hex_lower")

ConsoleWrite("Expected: " & $sExpectedSeed & @CRLF)
ConsoleWrite("Computed: " & $sComputedSeed & @CRLF)

; 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
$oBdSeed = ObjCreate("Chilkat.BinData")
$oBdSeed.AppendEncoded($sComputedSeed,"hex_lower")
$oCrypt.EncodingMode = "hex_lower"
$oCrypt.HashAlgorithm = "sha512"
$oCrypt.SetMacKeyString("Bitcoin seed")
Local $sHmacSha512_hex = $oCrypt.MacBdENC($oBdSeed)

$oBdHmac = ObjCreate("Chilkat.BinData")
$oBdHmac.AppendEncoded($sHmacSha512_hex,"hex_lower")

$oBdXprv = ObjCreate("Chilkat.BinData")
$oBdXprv.AppendEncoded("0488ade4","hex_lower")
$oBdXprv.AppendEncoded("000000000000000000","hex_lower")
$oBdXprv.AppendEncoded($oBdHmac.GetEncodedChunk(32,32,"hex_lower"),"hex_lower")
$oBdXprv.AppendByte(0)
$oBdXprv.AppendEncoded($oBdHmac.GetEncodedChunk(0,32,"hex_lower"),"hex_lower")

; Double hash using SHA256
$oCrypt.EncodingMode = "hex_lower"
$oCrypt.HashAlgorithm = "sha256"

$oBdHash = ObjCreate("Chilkat.BinData")
$oBdHash.AppendEncoded($oCrypt.HashBdENC($oBdXprv),"hex_lower")
Local $secondHash = $oCrypt.HashBdENC($oBdHash)
$oBdHash.Clear()
$oBdHash.AppendEncoded($secondHash,"hex_lower")

; Append the 1st 4 bytes of the bdHash to bdXprv.
$oBdXprv.AppendEncoded($oBdHash.GetEncodedChunk(0,4,"hex_lower"),"hex_lower")

; Base58 encode bdXprv
Local $sComputedMasterKey = $oBdXprv.GetEncoded("base58")

ConsoleWrite("Expected Master Key: " & $sExpectedMasterKey & @CRLF)
ConsoleWrite("Computed Master Key: " & $sComputedMasterKey & @CRLF)