if you want to encrypt the file *securely*

Heres a little theory/tutorial for EASY encryption and incredibly hard decryption (for hackers).

//----------------------------------------------------------------------------

GCC MATH IS GREAT

= 0

a = 1

b = 2

c = 3

d = 4

e = 5

f = 6

g = 7

h = 8

i = 9

j = 10

k = 11

l = 12

m = 13

n = 14

o = 15

p = 16

q = 17

r = 18

s = 19

t = 20

u = 21

v = 22

w = 23

x = 24

y = 25

z = 26

message (dimension arbitrary) = [M]

[(7 3 3)

(0 13 1)

(20 8 0)

(9 19 0)

(7 18 5)

(1 20 0)]

encoder = [E]

[(1 -2 2)

(-1 1 3)

(1 -1 -4)]

coded = [M]*[E] = [C]

[(7 -14 11)

(-12 12 35)

(12 -32 64)

(-10 1 75)

(-6 -1 48)

(-19 18 62)]

decoder = [E]^-1

[(-1 -10 -8)

(-1 -6 -5)

(0 -1 -1)]

decoded = [M]*[E]*[E]^-1 = [C]*[E]^-1 => [M]*[I] = [C]*[E]^-1 => [M] = [C]*[E]^-1

[(7 3 3)

(0 13 1)

(20 8 0)

(9 19 0)

(7 18 5)

(1 20 0)]

//------------------------------------------------------------------------------

Your message matrix determines your encryption matrix, specifficaly the COLUMNS (vertical). If your message matrix is 2x6 then your encryption matrix would be a 6x6 matrix.

Keep in mind the larger your encryption matrix is, the less likely it can be brute forced. Also, use Sparse number in odd ranges, 1 -235 3000000000 888 are good ranges, while 1 3 9 and 7 would be likely to be found in a brute force program.

Also note that you encryption matrix MUST, i repeat MUST have an inverse matrix, to check, get out a graphing calculator, enter the matrix and press inverse key followed by enter and copy that down.