R3CTF2025 Writeup

R3的题还是太顶了，题量大但只会签到（

Forensics

The R3 Pig Problem

打开可以看到很多tcp流，这些tcp流的时间戳存在规律

提取出来，计算时间差，接近0.02的记为0，接近0.1的记为1

def classify_time_diff(diff):
    if abs(diff - 0.02) < abs(diff - 0.1):
        return '0'
    else:
        return '1'
def process_file(filename):
    with open(filename, 'r') as f:
        lines = f.readlines()

    result = []

    i = 1 
    while i < len(lines)-1:
        try:
            current = float(lines[i+2].strip())
            previous = float(lines[i].strip())
            diff = current - previous
            bit = classify_time_diff(diff)
            result.append(bit)
        except ValueError:
            print(f"跳过无效行: 第 {i+1} 行")
        i += 2 

    return ''.join(result)

if __name__ == '__main__':
    input_file = 'output.txt' 
    binary_string = process_file(input_file)
    print(binary_string)