Encryption/Decryption Function

[loudar]

Hey everyone! Wrote two little functions that will encrypt/decrypt any given string with the two keys rawkey$ (it will be redefined after completing the first encryption). The two encryptions on top of each other also make bruteforcing pretty much impossible.
The code generated is different each time, even with the same input and the same keys.

Use this for your programs when saving passwords or other data you don't want to be read out ;)

I also wrote a program that will do the same, but you'll have a little menu to navigate around and can easily copy/paste data to/from clipboard if you don't want to automatically write files but e.g. send messages or similar:
https://loudar.myportfolio.com/cara

Code: QB64: [Select]

1. 'variables for encryption
2. length = 1000
3. DIM rndlet(length) AS INTEGER
4. DIM addlet(length) AS STRING
5. DIM finalASC(length) AS INTEGER
6. DIM toadd(length) AS STRING
7. DIM keyasc(length) AS INTEGER
8. DIM rawlet(length) AS STRING
9.  
10. 'variables for decryption
11. DIM findpos(length) AS INTEGER
12. DIM number(length) AS STRING
13. DIM ascvalue(length) AS INTEGER
14. DIM cryptletter(length) AS STRING

Code: QB64: [Select]

1. FUNCTION encrypt$ (rawdata$)
2.     encrun = 0
3.     DO
4.         encrun = encrun + 1
5.         IF encrun = 1 THEN
6.             rawkey$ = "enter the first key here"
7.         ELSE
8.             rawkey$ = "enter the second key here"
9.         END IF
10.         length = LEN(rawdata$)
11.         DIM rndlet(length) AS INTEGER
12.         DIM addlet(length) AS STRING
13.         DIM keyasc(length) AS INTEGER
14.         DIM rawlet(length) AS STRING
15.         DIM finalASC(length) AS INTEGER
16.         DIM toadd(length) AS STRING
17.         c = 0
18.         DO
19.             c = c + 1
20.  
21.             genRNDLET:
22.             rndlet(c) = INT(RND * 90) + 32
23.             IF rndlet(c) > 47 THEN
24.                 IF rndlet(c) < 68 THEN
25.                     GOTO genRNDLET
26.                 END IF
27.             END IF
28.             addlet$(c) = CHR$(rndlet(c))
29.  
30.             genFINALASC:
31.             l = 0
32.             DO
33.                 l = l + 1
34.                 keylet$ = MID$(rawkey$, l, 1)
35.                 keyasc(c) = keyasc(c) + ASC(keylet$)
36.             LOOP UNTIL l = LEN(rawkey$)
37.             rawlet$(c) = MID$(rawdata$, c, 1)
38.             finalASC(c) = ASC(rawlet$(c)) + keyasc(c) + rndlet(c)
39.  
40.             toadd$(c) = addlet$(c) + MID$(STR$(finalASC(c)), 2, LEN(STR$(finalASC(c) - 1)))
41.             edata$ = edata$ + toadd$(c)
42.         LOOP UNTIL c = LEN(rawdata$)
43.         IF encrun = 1 THEN
44.             rawdata$ = edata$
45.         ELSE
46.             encrypt$ = edata$
47.         END IF
48.         rawkey$ = ""
49.     LOOP UNTIL encrun = 2
50. END FUNCTION

Code: QB64: [Select]

1. FUNCTION decrypt$ (edata$)
2.     decrun = 0
3.     DO
4.         decrun = decrun + 1
5.         IF decrun = 1 THEN
6.             rawkey$ = "enter the second key from encrypt$ here"
7.         ELSE
8.             rawkey$ = "enter the first key from encrypt$ here"
9.         END IF
10.         u = 0
11.         DO
12.             u = u + 1
13.             number$(u) = ""
14.         LOOP UNTIL u = LEN(edata$)
15.         l = 0
16.         DO
17.             l = l + 1
18.             keyasc(l) = 0
19.         LOOP UNTIL l = LEN(rawkey$)
20.  
21.         c = 0
22.         letpos = 0
23.         DO
24.             letpos = letpos + 1
25.             IF ASC(MID$(edata$, letpos, 1)) > 32 THEN
26.                 IF ASC(MID$(edata$, letpos, 1)) < 48 OR ASC(MID$(edata$, letpos, 1)) > 57 THEN
27.                     c = c + 1
28.                     rndlet(c) = ASC(MID$(edata$, letpos, 1))
29.                     findpos(c) = letpos
30.                     endsearch = 0
31.                     DO
32.                         letpos = letpos + 1
33.                         IF letpos = LEN(edata$) + 1 THEN
34.                             GOTO endsearch
35.                         END IF
36.                         IF ASC(MID$(edata$, letpos, 1)) > 47 THEN
37.                             IF ASC(MID$(edata$, letpos, 1)) < 58 THEN
38.                             ELSE
39.                                 endsearch = 1
40.                             END IF
41.                         ELSE
42.                             endsearch = 1
43.                         END IF
44.                     LOOP UNTIL endsearch = 1
45.                     endsearch:
46.                     letpos = letpos - 1
47.                     numbers = letpos - findpos(c)
48.                     u = 0
49.                     DO
50.                         u = u + 1
51.                         number$(c) = number$(c) + MID$(edata$, findpos(c) + u, 1)
52.                     LOOP UNTIL u = numbers
53.                     ascvalue(c) = VAL(number$(c))
54.                     l = 0
55.                     DO
56.                         l = l + 1
57.                         keylet$ = MID$(rawkey$, l, 1)
58.                         keyasc(c) = keyasc(c) + ASC(keylet$)
59.                     LOOP UNTIL l = LEN(rawkey$)
60.                     cryptletter$(c) = CHR$(ascvalue(c) - keyasc(c) - rndlet(c))
61.                     rawdata$ = rawdata$ + cryptletter$(c)
62.                 END IF
63.             END IF
64.             continue:
65.         LOOP UNTIL letpos = LEN(edata$)
66.         IF decrun = 1 THEN
67.             edata$ = rawdata$
68.         ELSE
69.             decrypt$ = rawdata$
70.         END IF
71.         rawdata$ = ""
72.     LOOP UNTIL encrun = 2
73. END FUNCTION