In the first section, we discussed how to generate the key, which describes how to use this key to encrypt and decrypt a string.
The following code is the function that can implement this function at the same time
crypt.asp file
<%
Dim G_key
Const G_cryptthis = "Now is"
All good men to come to the aid of their country.
Const g_keylocation = "C:key.txt"
G_key = Mid (Readkeyfromfile (g_keylocation), 1,len (G_cryptthis))
Response.Write "<p>original STRING:" & g_cryptthis & "<p>"
Response.Write "<p>key VALUE:" & G_key & "<p>"
Response.Write "<p>encrypted cyphertext:" & EnCrypt (g_cryptthis) & "<p>"
Response.Write "<p>decrypted cyphertext:" & DeCrypt (EnCrypt (g_cryptthis)) & "<p>"
Function EnCrypt (Strcryptthis)
Dim Strchar, Ikeychar, Istringchar, I
For I = 1 to Len (strcryptthis)
Ikeychar = ASC (Mid (g_key,i,1))
Istringchar = ASC (Mid (strcryptthis,i,1))
' * * * * Uncomment below to encrypt with addition,
' Icryptchar = Istringchar + Ikeychar
Icryptchar = Ikeychar Xor Istringchar
strencrypted = strencrypted & Chr (Icryptchar)
Next
EnCrypt = strencrypted
End Function
Function DeCrypt (strencrypted)
Dim Strchar, Ikeychar, Istringchar, I
For I = 1 to Len (strencrypted)
Ikeychar = (ASC (mid g_key,i,1))
Istringchar = ASC (Mid (strencrypted,i,1))
' * * * * Uncomment below to decrypt with subtraction
' Idecryptchar = Istringchar-ikeychar
Idecryptchar = Ikeychar Xor Istringchar
strdecrypted = strdecrypted & Chr (Idecryptchar)
Next
DeCrypt = strdecrypted
End Function
Function Readkeyfromfile (strFileName)
Dim KeyFile, FSO, F
Set fso = Server.CreateObject ("Scripting.FileSystemObject")
Set F = fso. GetFile (strFileName)
Set ts = F.openastextstream (1,-2)
