binhexa

Description

Solution

1. Step 1Understand the challenge
   Each run gives a series of six questions that perform operations on two binary numbers. The values below are from one walkthrough; your connection will use different operands. Use the Binary Calculator tool for most of these conversions since it handles AND/OR/XOR, addition, and bit shifts without mistakes.
   Learn more

   Binary is base-2 notation - numbers are represented using only the digits 0 and 1. Every bit position represents a power of 2 (1, 2, 4, 8, 16, ...), just as every digit in decimal represents a power of 10. Understanding binary arithmetic is foundational to all of computing: CPUs operate in binary at the hardware level, and bitwise operations are used everywhere from networking (subnet masks) to cryptography (XOR ciphers) to data compression.

   The six operations in this challenge cover the core bitwise and arithmetic operations:

   • AND (&) - outputs 1 only when both input bits are 1. Used for masking: isolating specific bits by ANDing with a mask.
   • OR (|) - outputs 1 when at least one input bit is 1. Used for setting bits: forcing specific positions to 1.
   • Left shift (<<) - shifts all bits left by N positions, appending zeros on the right. Equivalent to multiplying by 2^N.
   • Right shift (>>) - shifts all bits right by N positions, discarding the rightmost bits. Equivalent to integer division by 2^N.
   • Addition (+) - standard binary addition with carry propagation, identical in principle to decimal addition.
   • Multiplication (*) - binary long multiplication; equivalent to repeated addition and shifting.

   The final step asks you to convert the result to hexadecimal. Hex(base-16) is a compact representation of binary: each hex digit maps exactly to 4 binary bits (a "nibble"). Programmers use hex because it is far more readable than long binary strings - a 32-bit value needs 32 binary digits but only 8 hex digits.

1. Step 1Bitwise AND (&)

   Compute 11010100 & 00100001

   Answer: 00000000

   Any overlapping 1 bits survive the AND; otherwise the result bit is 0.

2. Step 2Bitwise OR (|)

   Compute 11010100 | 00100001

   Answer: 11110101

   OR preserves 1s from either operand. RapidTables' binary calculator makes this trivial.

3. Step 3Binary multiplication (×)

   Multiply 11010100 * 00100001

   Answer: 1101101010100

   Binary multiplication mirrors base-10 long multiplication: stack the numbers and shift addends.

4. Step 4Left shift (<<)

   Shift 11010100 left by 1 bit

   Answer: 110101000

   Appending a single 0 on the right multiplies the number by two.

5. Step 5Addition (+)

   Compute 11010100 + 00100001

   Answer: 11110101

   Binary addition carries just like decimal math, so watch the carry chain in the middle bits.

6. Step 6Right shift (>>)

   Shift 00100001 right by 1 bit

   Answer: 10000

   A right shift divides by two, chopping the least-significant bit.

Helpful resources

• Binary Calculator
• Bit Shift Calculator
• Binary → Hex Converter

Related guides

Flag

picoCTF{b1tw^3se_0p3eR@tI0n_su33essFuL_aea...}

After answering all six prompts correctly, the service asks for the hexadecimal form of the final value (10000₂ = 0x10). Submit that answer to receive the flag above.