by Luis Mariscal (11 Submissions)
Category: Encryption
Compatability: VB 6.0
Difficulty: Unknown Difficulty
Originally Published: Mon 20th December 2004
Date Added: Mon 8th February 2021
Rating: 
(1 Votes)
How to verify a Valid Credit Card Number
API Declarations
' [email protected]
'###############################################################
dim n$(2000)
VBcoders
If card = "" Or Len(card) > 16 Or Len(card) < 16 Then
card = "1111111111111111"
End If
dos = 2
nueve = 9
'lee el numero de la tarjeta
For i = 1 To Len(card)
n$(i) = Mid$(card, i, 1)
a = Val(n$(1))
a = a * dos
If a > nueve Then
a = a - nueve
End If
b = Val(n$(2))
c = Val(n$(3))
c = c * dos
If c > nueve Then
c = c - nueve
End If
d = Val(n$(4))
e = Val(n$(5))
e = e * dos
If e > nueve Then
e = e - nueve
End If
f = Val(n$(6))
g = Val(n$(7))
g = g * dos
If g > nueve Then
g = g - nueve
End If
h = Val(n$(8))
j = Val(n$(9))
j = j * dos
If j > nueve Then
j = j - nueve
End If
k = Val(n$(10))
l = Val(n$(11))
l = l * dos
If l > nueve Then
l = l - nueve
End If
m = Val(n$(12))
r = Val(n$(13))
r = r * dos
If r > nueve Then
r = r - nueve
End If
o = Val(n$(14))
p = Val(n$(15))
p = p * dos
If p > nueve Then
p = p - nueve
End If
q = Val(n$(16))
Next
final = a + b + c + d + e + f + g + h + j + k + l + m + r + o + p + q
If final < 150 Then
tarjeta = 9999
End If
caca = final / 10
fr$ = Str$(caca) & "0"
ght = Val(fr$)
xc = final - ght
If xc = 0 Then
' registrada
valid = "Valid"
End If
If xc <> 0 Or final > 150 Then
' no registrada
valid = "Invalid"
End If
