1 files changed, 41 insertions, 0 deletions
diff --git a/implementations/vhdl/add_vhdltbc/encrypt/inner_sbox_b.vhd b/implementations/vhdl/add_vhdltbc/encrypt/inner_sbox_b.vhd
new file mode 100644
index 0000000..46f757e
--- /dev/null
+++ b/implementations/vhdl/add_vhdltbc/encrypt/inner_sbox_b.vhd
@@ -0,0 +1,41 @@
+library IEEE;
+library work;
+use IEEE.std_logic_1164.all;
+
+entity inner_sbox_b is
+  port(
+    sbox_i  : in  std_logic_vector(3 downto 0);
+    sbox_o : out std_logic_vector(3 downto 0)
+    );
+end inner_sbox_b;
+
+
+architecture inner_sbox_b_arch of inner_sbox_b is
+
+signal a,b,c,d,x,y,z,t 	:std_logic;
+signal c1,d1				:std_logic;
+
+begin
+
+a <= sbox_i(3);
+b <= sbox_i(2);
+c <= sbox_i(1);
+d <= sbox_i(0);
+
+
+c1 <= c xor (a and d);
+d1 <= b xor (d and c);
+
+
+x <= d xor (a and d1);
+y <= d1;
+z <= a xor (c1 and d1);
+t <= c1;
+
+sbox_o(3) <= x;
+sbox_o(2) <= y;
+sbox_o(1) <= z;
+sbox_o(0) <= t;
+                              
+end;
+