Binary Bomb Phase 5. What is the key phrase, to the assembly code?

I'm trying to figure out was is the keyphrase to this Phase5, From the beginning of the code it looks like the keyphrase is

a string of 6 chracters, then it loops 6 times on the string, and modifies it. But Im not sure what numbers are used in the modification.

Thank you.

(gdb) disas Dump of assembler code for function phase_5: => 0x00000000004011b8 <+0>: push %rbx 0x00000000004011b9 <+1>: mov %rdi,%rbx 0x00000000004011bc <+4>: callq 0x401431 0x00000000004011c1 <+9>: cmp $0x6,%eax 0x00000000004011c4 <+12>: je 0x4011cb 0x00000000004011c6 <+14>: callq 0x40171e 0x00000000004011cb <+19>: mov %rbx,%rax 0x00000000004011ce <+22>: lea 0x6(%rbx),%rdi 0x00000000004011d2 <+26>: mov $0x0,%ecx 0x00000000004011d7 <+31>: movzbl (%rax),%edx 0x00000000004011da <+34>: and $0xf,%edx 0x00000000004011dd <+37>: add 0x402780(,%rdx,4),%ecx 0x00000000004011e4 <+44>: add $0x1,%rax 0x00000000004011e8 <+48>: cmp %rdi,%rax 0x00000000004011eb <+51>: jne 0x4011d7 0x00000000004011ed <+53>: cmp $0x35,%ecx 0x00000000004011f0 <+56>: je 0x4011f7 0x00000000004011f2 <+58>: callq 0x40171e 0x00000000004011f7 <+63>: pop %rbx 0x00000000004011f8 <+64>: retq End of assembler dump.