✅Puzzle 5

DUP, MUL, PUSH, EQ, JUMPI

Puzzle

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# Puzzle 5 #
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00      34          CALLVALUE
01      80          DUP1
02      02          MUL
03      610100      PUSH2 0100
06      14          EQ
07      600C        PUSH1 0C
09      57          JUMPI
0A      FD          REVERT
0B      FD          REVERT
0C      5B          JUMPDEST
0D      00          STOP
0E      FD          REVERT
0F      FD          REVERT

? Enter the value to send: (0) 

Solution

Up until address 0x06, the program compares msg.value ** 2 with 0x100. Since we want JUMPI(0x0C, 1) in order to jump to address 0x0C, we need msg.value ** 2 == 0x100. 0x100 is 256 in decimal, so our input should be sqrt(256) = 16.