B4X

HOTP Algorithm: HMAC-Based One-Time Password Algorithm

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Demonstrates how to generate an HMAC one-time password (HOTP) as specified in RFC 4226.

Note: This example requires Chilkat v9.5.0.77 or greater.

B4X

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

Dim crypt As ChilkatCrypt2
crypt.Initialize("crypt")

'  Duplicate the following results from RFC 4226

'  Appendix D - HOTP Algorithm: Test Values
'  
'    The following test data uses the ASCII string
'    "12345678901234567890" for the secret:
'  
'    Secret = 0x3132333435363738393031323334353637383930
'  
'                      Truncated
'    Count    Hexadecimal    Decimal        HOTP
'    0        4c93cf18       1284755224     755224
'    1        41397eea       1094287082     287082
'    2         82fef30        137359152     359152
'    3        66ef7655       1726969429     969429
'    4        61c5938a       1640338314     338314
'    5        33c083d4        868254676     254676
'    6        7256c032       1918287922     287922
'    7         4e5b397         82162583     162583
'    8        2823443f        673399871     399871
'    9        2679dc69        645520489     520489

Dim secret As String = "12345678901234567890"
Dim count As Int
For count = 0 To 9
    Dim counterHex As String = crypt.EncodeInt(count, 8, False, "hex")
    Dim hotp As String = crypt.Hotp(secret, "ascii", counterHex, 6, -1, "sha1")
    Log(count & "  HOTP = " & hotp)
Next

'  Output is:
'  0  HOTP = 755224
'  1  HOTP = 287082
'  2  HOTP = 359152
'  3  HOTP = 969429
'  4  HOTP = 338314
'  5  HOTP = 254676
'  6  HOTP = 287922
'  7  HOTP = 162583
'  8  HOTP = 399871
'  9  HOTP = 520489