{"id":203,"date":"2025-07-26T10:49:45","date_gmt":"2025-07-26T02:49:45","guid":{"rendered":"https:\/\/blog.llxyy.top\/?p=203"},"modified":"2025-07-26T10:49:45","modified_gmt":"2025-07-26T02:49:45","slug":"%e5%82%85%e9%87%8c%e5%8f%b6%e5%8f%98%e6%8d%a2-%e5%b9%85%e5%ba%a6%e8%b0%b1%e5%92%8c%e7%9b%b8%e4%bd%8d%e8%b0%b1","status":"publish","type":"post","link":"http:\/\/blog.llxyy.top\/index.php\/2025\/07\/26\/%e5%82%85%e9%87%8c%e5%8f%b6%e5%8f%98%e6%8d%a2-%e5%b9%85%e5%ba%a6%e8%b0%b1%e5%92%8c%e7%9b%b8%e4%bd%8d%e8%b0%b1\/","title":{"rendered":"\u5085\u91cc\u53f6\u53d8\u6362\u2014\u2014\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\">1.\u5085\u91cc\u53f6\u8f6c\u6362\u7684\u57fa\u7840\u6982\u5ff5<\/h3>\n\n\n\n<p>\u65f6\u57df\u4e0e\u9891\u57df\u7684\u5904\u7406\uff1a<\/p>\n\n\n\n<p>\u65f6\u57df\uff1a\u4fe1\u53f7\u968f\u65f6\u95f4\u53d8\u5316\u7684\u6837\u5b50\uff08\u6bd4\u5982\u5fc3\u8df3\u6ce2\u5f62\u3001\u58f0\u97f3\u7684\u632f\u52a8\uff09\u3002<\/p>\n\n\n\n<p>\u9891\u57df\uff1a\u4fe1\u53f7\u7531\u54ea\u4e9b\u9891\u7387\u7684\u6ce2\u7ec4\u6210\uff08\u6bd4\u5982\u4f4e\u97f3\u3001\u4e2d\u97f3\u3001\u9ad8\u97f3\u7684\u6bd4\u4f8b\uff09<\/p>\n\n\n\n<p>\u6838\u5fc3\u601d\u60f3\uff1a<\/p>\n\n\n\n<p>\u4efb\u4f55\u4fe1\u53f7\uff08\u6bd4\u5982\u58f0\u97f3\u3001\u56fe\u7247\uff09\u90fd\u53ef\u4ee5\u62c6\u89e3\u6210\u4e00\u5806\u4e0d\u540c\u9891\u7387\u7684\u201c\u6ce2\u201d\u7684\u7ec4\u5408\u3002<\/p>\n\n\n\n<p>\u6570\u5b66\u672c\u8d28\uff1a \u5085\u91cc\u53f6\u53d8\u6362\u7684\u516c\u5f0f\u672c\u8d28\u662f\u7528 \u6b63\u5f26\u6ce2\u548c\u4f59\u5f26\u6ce2\u7684\u53e0\u52a0 \u6765\u62df\u5408\u539f\u59cb\u4fe1\u53f7\u3002 \uff08\u516c\u5f0f\u53ef\u4ee5\u7b80\u5355\u7406\u89e3\u4e3a\uff1a\u4fe1\u53f7 = \u6ce21 + \u6ce22 + \u6ce23 + &#8230;\uff09<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">2.\u4ec0\u4e48\u662f\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31<\/h3>\n\n\n\n<p>\u9996\u5148\u6211\u4eec\u8981\u4e86\u89e3\u56fe\u7247\uff0c\u56fe\u7247\u7531\u50cf\u7d20\u7ec4\u6210\uff0c\u4e0e\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31\u6709\u5173\u7684\u5085\u91cc\u53f6\u53d8\u6362\uff0c\u5c31\u662f\u628a\u201c\u76f4\u63a5\u770b\u56fe\u201d\u8f6c\u6210\u201c\u5206\u6790\u6ce2\u201d\uff0c\u800c\uff1a<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>\u5e45\u5ea6\u8c31\uff1a\u8fd9\u4e9b\u6ce2\u7684\u201c\u5f3a\u5f31\u201d\uff08\u6bd4\u5982\u4f4e\u9891\u6ce2\u5f3a=\u56fe\u7247\u6574\u4f53\u504f\u4eae\uff09\uff1b<\/li>\n<\/ol>\n\n\n\n<p>\u4f4e\u9891\uff1a\u56fe\u50cf\u5e73\u6ed1\u533a\u57df\uff08\u5982\u5929\u7a7a\u3001\u4eba\u8138\uff09\u3002<\/p>\n\n\n\n<p>\u9ad8\u9891\uff1a\u56fe\u50cf\u8fb9\u7f18\u548c\u7ec6\u8282\uff08\u5982\u6587\u5b57\u3001\u7eb9\u7406\uff09<\/p>\n\n\n\n<ol start=\"2\" class=\"wp-block-list\">\n<li>\u76f8\u4f4d\u8c31\uff1a\u8fd9\u4e9b\u6ce2\u7684\u201c\u600e\u4e48\u62fc\u6210\u56fe\u201d\uff08\u51b3\u5b9a\u5f62\u72b6\u548c\u7ed3\u6784\uff09\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u76f8\u4f4d\u51b3\u5b9a\u56fe\u50cf\u7684\u8f6e\u5ed3\u548c\u5f62\u72b6\uff0c\u5373\u4f7f\u5e45\u5ea6\u8c31\u76f8\u540c\uff0c\u76f8\u4f4d\u4e0d\u540c\uff0c\u56fe\u50cf\u4e5f\u4f1a\u5b8c\u5168\u4e0d\u540c\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">3.\u4f8b\u9898<\/h3>\n\n\n\n<p>SQCTF:FFT IFFT<\/p>\n\n\n\n<p>\u9996\u5148\u67e5\u770b\u9898\u76ee\u4ee3\u7801\u5206\u6790\u52a0\u5bc6\u8fc7\u7a0b<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>import os\nimport cv2\nimport struct\nimport numpy as np\n\n\ndef mapping(data, down=0, up=255, tp=np.uint8):\n    data_max = data.max()\n    data_min = data.min()\n    interval = data_max - data_min\n    new_interval = up - down\n    new_data = (data - data_min) * new_interval \/ interval + down\n    new_data = new_data.astype(tp)\n    return new_data\n\n\ndef fft(img):\n    fft = np.fft.fft2(img)\n    fft = np.fft.fftshift(fft)\n    m = np.log(np.abs(fft))\n    p = np.angle(fft)\n    return m, p\n\n\nif __name__ == '__main__':\n    os.mkdir('m')\n    os.mkdir('p')\n    os.mkdir('frame')\n    os.system('ffmpeg -i secret.mp4 frame\/%03d.png')    #\u89c6\u9891\u62c6\u5206\u591a\u5f20\u7167\u7247\n\n    files = os.listdir('frame')\n    r_file = open('r', 'wb')\n\n    for file in files:\n        img = cv2.imread(f'frame\/{file}', cv2.IMREAD_GRAYSCALE)     #\u8bfb\u53d6\u6240\u6709\u5e27\n\n        m, p = fft(img)\n        r_file.write(struct.pack('!ff', m.min(), m.max()))\n\n        new_img1 = mapping(m)               #\u7ed8\u5236\n        new_img2 = mapping(p)               #\u7ed8\u5236\n\n        cv2.imwrite(f'm\/{file}', new_img1)\n        cv2.imwrite(f'p\/{file}', new_img2)\n\n    r_file.close()\n    os.system('ffmpeg -i m\/%03d.png -r 25 -vcodec png 1.mkv')\n    os.system('ffmpeg -i p\/%03d.png -r 25 -vcodec png 2.mkv')<\/code><\/pre>\n\n\n\n<p>\u8fd9\u6bb5\u4ee3\u7801\u7684\u4e3b\u8981\u529f\u80fd\u662f\u5bf9\u89c6\u9891\u6587\u4ef6\u8fdb\u884c\u5085\u91cc\u53f6\u53d8\u6362\u5904\u7406\uff0c\u5e76\u751f\u6210\u76f8\u5173\u7684\u56fe\u50cf\u548c\u89c6\u9891\u6587\u4ef6\uff0c\u5177\u4f53\u529f\u80fd\u5982\u4e0b\uff1a<\/p>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li>\u89c6\u9891\u5e27\u63d0\u53d6\uff1a\n<ol class=\"wp-block-list\">\n<li>\u00a0\u00a0\u4f7f\u7528<code>ffmpeg<\/code>\u5c06\u8f93\u5165\u7684<code>secret.mp4<\/code>\u89c6\u9891\u6587\u4ef6\u62c6\u5206\u6210\u4e00\u7cfb\u5217\u5e27\u56fe\u50cf\uff0c\u4fdd\u5b58\u5230<code>frame<\/code>\u6587\u4ef6\u5939\u4e2d<\/li>\n<\/ol>\n<\/li>\n\n\n\n<li>\u5085\u91cc\u53f6\u53d8\u6362\u5904\u7406\uff1a\n<ol class=\"wp-block-list\">\n<li>\u5bf9\u6bcf\u4e00\u5e27\u56fe\u50cf\u8fdb\u884c\u7070\u5ea6\u5904\u7406<ol start=\"1\"><li>\u00a0\u00a0\u6267\u884c\u4e8c\u7ef4\u5085\u91cc\u53f6\u53d8\u6362\uff0c\u5e76\u5c06\u9891\u8c31\u79fb\u5230\u4e2d\u5fc3<\/li><\/ol><ol start=\"1\"><li>\u00a0\u00a0\u8ba1\u7b97\u5085\u91cc\u53f6\u53d8\u6362\u7684\u5e45\u5ea6\u8c31\uff08<code>m<\/code>\uff09\u548c\u76f8\u4f4d\u8c31\uff08<code>p<\/code>\uff09<\/li><\/ol>\n<ol start=\"1\" class=\"wp-block-list\">\n<li>\u00a0\u00a0\u5e45\u5ea6\u8c31\u901a\u8fc7\u53d6\u5bf9\u6570\u8fdb\u884c\u5904\u7406\uff08<code>np.log(np.abs(fft))<\/code>\uff09<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/li>\n\n\n\n<li>\u6570\u636e\u6620\u5c04\u4e0e\u4fdd\u5b58\uff1a\n<ol class=\"wp-block-list\">\n<li>\u5c06\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31\u7684\u503c\u6620\u5c04\u5230 0-255 \u8303\u56f4\uff08\u4fbf\u4e8e\u53ef\u89c6\u5316\uff09\n<ol start=\"1\" class=\"wp-block-list\">\n<li>\u00a0\u00a0\u5c06\u6620\u5c04\u540e\u7684\u5e45\u5ea6\u8c31\u4fdd\u5b58\u5230<code>m<\/code>\u6587\u4ef6\u5939\uff0c\u76f8\u4f4d\u8c31\u4fdd\u5b58\u5230<code>p<\/code>\u6587\u4ef6\u5939<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/li>\n\n\n\n<li>\u751f\u6210\u7edf\u8ba1\u6570\u636e\uff1a\n<ol class=\"wp-block-list\">\n<li>\u00a0\u00a0\u521b\u5efa<code>r<\/code>\u6587\u4ef6\uff0c\u4ee5\u4e8c\u8fdb\u5236\u5f62\u5f0f\u5b58\u50a8\u6bcf\u5e27\u5e45\u5ea6\u8c31\u7684\u6700\u5c0f\u503c\u548c\u6700\u5927\u503c<\/li>\n<\/ol>\n<\/li>\n\n\n\n<li>\u751f\u6210\u8f93\u51fa\u89c6\u9891\uff1a\n<ol class=\"wp-block-list\">\n<li>\u4f7f\u7528<code>ffmpeg<\/code>\u5c06<code>m<\/code>\u6587\u4ef6\u5939\u4e2d\u7684\u5e45\u5ea6\u8c31\u56fe\u50cf\u5408\u6210\u4e3a<code>1.mkv<\/code>\u89c6\u9891\n<ol start=\"1\" class=\"wp-block-list\">\n<li>\u00a0\u00a0\u5c06<code>p<\/code>\u6587\u4ef6\u5939\u4e2d\u7684\u76f8\u4f4d\u8c31\u56fe\u50cf\u5408\u6210\u4e3a<code>2.mkv<\/code>\u89c6\u9891<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n\n\n\n<p>fft = np.fft.fft2(img) # \u5bf9\u56fe\u50cf\u505a\u4e8c\u7ef4\u5085\u91cc\u53f6\u53d8\u6362<\/p>\n\n\n\n<p>fft = np.fft.fftshift(fft) # \u5c06\u96f6\u9891\uff08\u4f4e\u9891\uff09\u79fb\u5230\u4e2d\u5fc3<\/p>\n\n\n\n<p>m = np.log(np.abs(fft)) # \u63d0\u53d6\u5e45\u5ea6\u8c31\uff0c\u7528\u5bf9\u6570\u538b\u7f29\u52a8\u6001\u8303\u56f4<\/p>\n\n\n\n<p>p = np.angle(fft) # \u63d0\u53d6\u76f8\u4f4d\u8c31<\/p>\n\n\n\n<p>\u90a3\u4e48\u6211\u4eec\u53ef\u4ee5\u7528\u811a\u672c\u6062\u590d\u4e00\u4e0b<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>import os\nimport cv2\nimport struct\nimport numpy as np\nimport shutil\n\n\ndef inverse_mapping(data, orig_min, orig_max, tp=np.float64):\n    <em>\"\"\"\u5c060-255\u8303\u56f4\u7684\u56fe\u50cf\u6620\u5c04\u56de\u539f\u59cb\u6570\u636e\u8303\u56f4\"\"\"<\/em>data = data.astype(np.float64)\n    new_data = data * (orig_max - orig_min) \/ 255 + orig_min\n    return new_data.astype(tp)\n\n\ndef ifft(m, p):\n    <em>\"\"\"\u4ece\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31\u8fdb\u884c\u9006\u5085\u91cc\u53f6\u53d8\u6362\"\"\"<\/em># \u7ec4\u5408\u5e45\u5ea6\u548c\u76f8\u4f4d\u4e3a\u590d\u6570\n    fft_complex = np.exp(m) * np.exp(1j * p)  # \u5e45\u5ea6\u8c31\u9700\u8981\u6307\u6570\u8fd8\u539f\uff08\u539f\u5904\u7406\u7528\u4e86log\uff09\n    # \u9006\u79fb\u4f4d\u548c\u9006\u5085\u91cc\u53f6\u53d8\u6362\n    fft_shift = np.fft.ifftshift(fft_complex)\n    img = np.fft.ifft2(fft_shift)\n    # \u53d6\u5b9e\u90e8\u5e76\u8f6c\u6362\u4e3a\u7070\u5ea6\u503c\u8303\u56f4\n    img = np.abs(img)\n    return img\n\n\ndef decrypt():\n    # \u521b\u5efa\u8f93\u51fa\u76ee\u5f55\n    os.makedirs('recovered_frame', exist_ok=True)\n\n    # \u8bfb\u53d6\u5e45\u5ea6\u8c31\u7684min\/max\u6570\u636e\n    with open('r', 'rb') as f:\n        data = f.read()\n    # \u89e3\u6790\u4e8c\u8fdb\u5236\u6570\u636e\uff08\u6bcf\u4e2a\u5e27\u5bf9\u5e94\u4e24\u4e2afloat\u503c\uff1amin\u548cmax\uff09\n    frame_count = len(data) \/\/ 8  # \u6bcf\u4e2afloat\u53604\u5b57\u8282\uff0c\u6bcf\u4e2a\u5e272\u4e2afloat\n    min_max_list = &#91;struct.unpack('!ff', data&#91;i * 8:(i + 1) * 8]) for i in range(frame_count)]\n\n    # \u83b7\u53d6\u5e76\u6392\u5e8f\u6240\u6709\u5e27\u6587\u4ef6\n    m_files = sorted(os.listdir('m'), key=lambda x: int(x.split('.')&#91;0]))\n    p_files = sorted(os.listdir('p'), key=lambda x: int(x.split('.')&#91;0]))\n\n    # \u9010\u5e27\u6062\u590d\n    for i, (m_file, p_file) in enumerate(zip(m_files, p_files)):\n        # \u8bfb\u53d6\u5e45\u5ea6\u8c31\u548c\u76f8\u4f4d\u8c31\u56fe\u50cf\n        m_img = cv2.imread(f'm\/{m_file}', cv2.IMREAD_GRAYSCALE)\n        p_img = cv2.imread(f'p\/{p_file}', cv2.IMREAD_GRAYSCALE)\n\n        # \u83b7\u53d6\u5f53\u524d\u5e27\u7684\u5e45\u5ea6\u8c31\u539f\u59cbmin\u548cmax\n        m_min, m_max = min_max_list&#91;i]\n\n        # \u5c06\u56fe\u50cf\u6620\u5c04\u56de\u539f\u59cb\u5085\u91cc\u53f6\u53d8\u6362\u7684\u5e45\u5ea6\u548c\u76f8\u4f4d\n        m = inverse_mapping(m_img, m_min, m_max)\n        p = inverse_mapping(p_img, -np.pi, np.pi)  # \u76f8\u4f4d\u8303\u56f4\u662f&#91;-\u03c0, \u03c0]\n\n        # \u9006\u5085\u91cc\u53f6\u53d8\u6362\u6062\u590d\u56fe\u50cf\n        recovered_img = ifft(m, p)\n\n        # \u6620\u5c04\u52300-255\u7070\u5ea6\u8303\u56f4\u5e76\u4fdd\u5b58\n        recovered_img = ((recovered_img - recovered_img.min()) \/\n                         (recovered_img.max() - recovered_img.min()) * 255).astype(np.uint8)\n        cv2.imwrite(f'recovered_frame\/{m_file}', recovered_img)\n        print(f'\u5df2\u6062\u590d\u5e27 {i + 1}\/{len(m_files)}')\n\n    # \u7528ffmpeg\u5c06\u6062\u590d\u7684\u5e27\u5408\u6210\u4e3a\u89c6\u9891\n    os.system('ffmpeg -i recovered_frame\/%03d.png -r 25 -vcodec libx264 recovered.mp4')\n    print('\u89e3\u5bc6\u5b8c\u6210\uff0c\u8f93\u51fa\u89c6\u9891\uff1arecovered.mp4')\n\n\nif __name__ == '__main__':\n    # \u6e05\u7406\u4e4b\u524d\u7684\u6062\u590d\u7ed3\u679c\uff08\u53ef\u9009\uff09\n    if os.path.exists('recovered_frame'):\n        shutil.rmtree('recovered_frame')\n    decrypt()<\/code><\/pre>\n\n\n\n<p>\u89e3\u5bc6\u6210\u529f\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/blog.llxyy.top\/wp-content\/uploads\/2025\/07\/0f197147-aaf8-4082-ac68-266c6403b49f.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"1059\" height=\"941\" data-original=\"https:\/\/blog.llxyy.top\/wp-content\/uploads\/2025\/07\/0f197147-aaf8-4082-ac68-266c6403b49f.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-204\"  sizes=\"auto, (max-width: 1059px) 100vw, 1059px\" \/><\/div><\/figure>\n\n\n\n<p>SQCTF{HELLO}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>1.\u5085\u91cc\u53f6\u8f6c\u6362\u7684\u57fa\u7840\u6982\u5ff5 \u65f6\u57df\u4e0e\u9891\u57df\u7684\u5904\u7406\uff1a \u65f6\u57df\uff1a\u4fe1\u53f7\u968f\u65f6\u95f4\u53d8\u5316\u7684\u6837\u5b50\uff08\u6bd4\u5982\u5fc3\u8df3\u6ce2\u5f62\u3001\u58f0\u97f3\u7684\u632f\u52a8\uff09\u3002 \u9891\u57df\uff1a [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-203","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/posts\/203","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/comments?post=203"}],"version-history":[{"count":1,"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/posts\/203\/revisions"}],"predecessor-version":[{"id":205,"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/posts\/203\/revisions\/205"}],"wp:attachment":[{"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/media?parent=203"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/categories?post=203"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blog.llxyy.top\/index.php\/wp-json\/wp\/v2\/tags?post=203"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}