Obfunge

Obfunge is a Befunge-93 derivative invented by User:None1, it is Befunge-93 but obfuscated.

Instructions

Befunge-93 has the following commands:

Cmd	Description
!	Addition: Pop two values a and b, then push the result of a+b
"	Subtraction: Pop two values a and b, then push the result of b-a
#	Multiplication: Pop two values a and b, then push the result of a*b
$	Integer division: Pop two values a and b, then push the result of b/a, rounded down. According to the specifications, if a is zero, ask the user what result they want.
%	Modulo: Pop two values a and b, then push the remainder of the integer division of b/a.
&	Logical NOT: Pop a value. If the value is zero, push 1; otherwise, push zero.
'	Greater than: Pop two values a and b, then push 1 if b>a, otherwise zero.
(	PC direction right
)	PC direction left
*	PC direction up
+	PC direction down
,	Random PC direction
-	Horizontal IF: pop a value; set direction to right if value=0, set to left otherwise
.	Vertical IF: pop a value; set direction to down if value=0, set to up otherwise
/	Toggle stringmode (push each character's ASCII value all the way up to the next /)
0	Duplicate top stack value
1	Swap top stack values
2	Pop top of stack and discard
3	Pop top of stack and output as integer
4	Pop top of stack and output as ASCII character
5	Bridge: jump over next command in the current direction of the current PC
6	A "get" call (a way to retrieve data in storage). Pop two values y and x, then push the ASCII value of the character at that position in the program. If (x,y) is out of bounds, push 0
7	A "put" call (a way to store a value for later use). Pop three values y, x and v, then change the character at the position (x,y) in the program to the character with ASCII value v
8	Get integer from user and push it
9	Get character from user and push it
:	End program
;<=>?@ABCD	Equivalent to Befunge-93's 0 to 9

Do you think that's all? No! The program must be decrypted first!

Encryption is done using the following method:

e[i][j]=(a[i][j]+3*a[i][j-1]+5*a[i-1][j]-7*a[i-1][j-1])%94

Where e[i][j] stands for the encrypted character, a[i][j] stands for the original character, using this encoding:

(space)!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~

Decryption can be done like this:

a[i][j]=(e[i][j]-3*a[i][j-1]-5*a[i-1][j]+7*a[i-1][j-1])%94