XProfan

def cryptacquirecontext(5) !"Advapi32.dll","CryptAcquireContextA"
def cryptcreatehash(5) !"Advapi32.dll","CryptCreateHash"
def cryptdecrypt(6) !"Advapi32.dll","CryptDecrypt"
def cryptderivekey(5) !"Advapi32.dll","CryptDeriveKey"
def cryptdestroyhash(1) !"Advapi32.dll","CryptDestroyHash"
def cryptdestroykey(1) !"Advapi32.dll","CryptDestroyKey"
def cryptencrypt(7) !"Advapi32.dll","CryptEncrypt"
def crypthashdata(4) !"Advapi32.dll","CryptHashData"
def cryptreleasecontext(2) !"Advapi32.dll","CryptReleaseContext"

proc encode

    parameters txt$,schl$
    declare erg$,hh&,hk&,hp&,len&,puffer#
    cryptacquirecontext(addr(hp&),0,0,1,0)
    len&=len(txt$)
    dim puffer#,len&+2+128
    string puffer#,0=txt$

    if hp&

        cryptcreatehash(hp&,32771,0,0,addr(hh&))

        if hh&

            crypthashdata(hh&,addr(schl$),len(schl$),0)
            cryptderivekey(hp&,26625,hh&,1,addr(hk&))

            if hk&

                cryptencrypt(hk&,0,1,0,puffer#,addr(len&),len(txt$)*2+128)
                cryptdestroykey(hk&)

            endif

            cryptdestroyhash(hh&)

        endif

        cryptreleasecontext(hp&,0)

    endif

    erg$=encode64(char$(puffer#,0,len&))
    dispose puffer#
    return erg$

endproc

proc decode

    parameters txt$,schl$
    declare erg$,hh&,hk&,hp&,len&,puffer#,tmp$
    cryptacquirecontext(addr(hp&),0,0,1,0)
    tmp$=decode64(txt$)
    len&=len(tmp$)
    dim puffer#,len&*2+128
    string puffer#,0=tmp$

    if hp&

        cryptcreatehash(hp&,32771,0,0,addr(hh&))

        if hh&

            crypthashdata(hh&,addr(schl$),len(schl$),0)
            cryptderivekey(hp&,26625,hh&,1,addr(hk&))

            if hk&

                if cryptdecrypt(hk&,0,1,0,puffer#,addr(len&))

                    erg$=string$(puffer#,0)

                endif

                cryptdestroykey(hk&)

            endif

            cryptdestroyhash(hh&)

        endif

        cryptreleasecontext(hp&,0)

    endif

    dispose puffer#
    return erg$

endproc

print decode(encode("INHALT","PASSWORT"),"PASSWORT")
waitinput