Text Encryption-Decryption

[ahenry3068]

A better way to do that is with a Seeded Random value and XOR ing the bytes.   It's pretty simple and the Random Number seed is the required key for decryption 

Code: (Select All)

Print

Print "ENTER A STRING TO ENCRYPT"

Line Input X$

Print

Print "STARTING STRING"

Print X$

Print



GETSEED:

Input "ENTER A SEED VALUE"; SEED



If SEED = 0 Then Print "INVALID SEED TRY AGAIN": Print: GoTo GETSEED

If SEED > 0 Then SEED = SEED * -1

X = Rnd(SEED)



CRYPT$ = ""

For I = 1 To Len(X$)

    MASK = Int(Rnd(1) * 255) + 1

    C$ = Mid$(X$, I, 1)

    C = Asc(C$)

    CRYPTBYTE = (C Or MASK) And Not (C And MASK): Rem XOR

    CRYPT$ = CRYPT$ + Chr$(CRYPTBYTE)

Next



Print "ENCRYPTED"

Print

Print CRYPT$

Print

X$ = ""



GETSEED2:

Input "ENTER THE SAME SEED TO DECRYPT"; NEWSEED



If NEWSEED = 0 Then Print "INVALID SEED TRY AGAIN": Print: GoTo GETSEED2

If NEWSEED > 0 Then NEWSEED = NEWSEED * -1



X = Rnd(NEWSEED)



For I = 1 To Len(CRYPT$)

    MASK = Int(Rnd(1) * 255) + 1

    C$ = Mid$(CRYPT$, I, 1)

    C = Asc(C$)

    CRYPTBYTE = (C Or MASK) And Not (C And MASK): Rem XOR

    X$ = X$ + Chr$(CRYPTBYTE)

Next



Print "DECRYPTED"

Print

Print X$

Print