GCHQ - The grid

exe:
011572A8 EB 04                jmp         exe+6 (11572AEh)
011572AA AF                   scas        dword ptr es:[edi]
011572AB C2 BF A3             ret         0A3BFh
011572AE 81 EC 00 01 00 00    sub         esp,100h
011572B4 31 C9                xor         ecx,ecx
011572B6 88 0C 0C             mov         byte ptr [esp+ecx],cl
011572B9 FE C1                inc         cl
011572BB 75 F9                jne         exe+0Eh (11572B6h)
011572BD 31 C0                xor         eax,eax
011572BF BA EF BE AD DE       mov         edx,0DEADBEEFh
011572C4 02 04 0C             add         al,byte ptr [esp+ecx]
011572C7 00 D0                add         al,dl
011572C9 C1 CA 08             ror         edx,8
011572CC 8A 1C 0C             mov         bl,byte ptr [esp+ecx]
011572CF 8A 3C 04             mov         bh,byte ptr [esp+eax]
011572D2 88 1C 04             mov         byte ptr [esp+eax],bl
011572D5 88 3C 0C             mov         byte ptr [esp+ecx],bh
011572D8 FE C1                inc         cl
011572DA 75 E8                jne         exe+1Ch (11572C4h)
011572DC E9 5C 00 00 00       jmp         exe+95h (115733Dh)
011572E1 89 E3                mov         ebx,esp
011572E3 81 C3 04 00 00 00    add         ebx,4
011572E9 5C                   pop         esp
011572EA 58                   pop         eax
011572EB 3D 41 41 41 41       cmp         eax,41414141h
011572F0 75 43                jne         exe+8Dh (1157335h)
011572F2 58                   pop         eax
011572F3 3D 42 42 42 42       cmp         eax,42424242h
011572F8 75 3B                jne         exe+8Dh (1157335h)
011572FA 5A                   pop         edx
011572FB 89 D1                mov         ecx,edx
011572FD 89 E6                mov         esi,esp
011572FF 89 DF                mov         edi,ebx
01157301 29 CF                sub         edi,ecx
01157303 F3 A4                rep movs    byte ptr es:[edi],byte ptr [esi]
01157305 89 DE                mov         esi,ebx
01157307 89 D1                mov         ecx,edx
01157309 89 DF                mov         edi,ebx
0115730B 29 CF                sub         edi,ecx
0115730D 31 C0                xor         eax,eax
0115730F 31 DB                xor         ebx,ebx
01157311 31 D2                xor         edx,edx
01157313 FE C0                inc         al
01157315 02 1C 06             add         bl,byte ptr [esi+eax]
01157318 8A 14 06             mov         dl,byte ptr [esi+eax]
0115731B 8A 34 1E             mov         dh,byte ptr [esi+ebx]
0115731E 88 34 06             mov         byte ptr [esi+eax],dh
01157321 88 14 1E             mov         byte ptr [esi+ebx],dl
01157324 00 F2                add         dl,dh
01157326 30 F6                xor         dh,dh
01157328 8A 1C 16             mov         bl,byte ptr [esi+edx]
0115732B 8A 17                mov         dl,byte ptr [edi]
0115732D 30 DA                xor         dl,bl
0115732F 88 17                mov         byte ptr [edi],dl
01157331 47                   inc         edi
01157332 49                   dec         ecx
01157333 75 DE                jne         exe+6Bh (1157313h)
01157335 31 DB                xor         ebx,ebx
01157337 89 D8                mov         eax,ebx
01157339 FE C0                inc         al
0115733B CD 80                int         80h
0115733D 90                   nop
0115733E 90                   nop
0115733F E8 9D FF FF FF       call        exe+39h (11572E1h)