Visual FoxPro

HOTP Algorithm: HMAC-Based One-Time Password Algorithm

See more Encryption Examples

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.

Visual FoxPro

LOCAL loCrypt
LOCAL lcSecret
LOCAL lnCount
LOCAL lcCounterHex
LOCAL lcHotp

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

loCrypt = CreateObject('Chilkat.Crypt2')

*  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

lcSecret = "12345678901234567890"

FOR lnCount = 0 TO 9
    lcCounterHex = loCrypt.EncodeInt(lnCount,8,0,"hex")
    lcHotp = loCrypt.Hotp(lcSecret,"ascii",lcCounterHex,6,-1,"sha1")
    ? STR(lnCount) + "  HOTP = " + lcHotp
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

RELEASE loCrypt