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