将得到的两种文本在线base64解码为图片,发现都失败
如果在chrome浏览器做,会发现得到的图片是透明的,说明确实是PNG文件,但信息损坏。 4.人工再检,正确文本
我们不禁怀疑,一开始S老师给出的文本中有错误。虽然经过几小时的检错后,我们已经将I和l的位置都审查结束,但在其他位置仍有可能存在错误。于是我们小组3人分工,一人负责900张左右的图片,对整个文本进行系统的再次检查(眼要瞎了...)
果然,发现存在五六处大小写错误,于是我们终于得到了最终的正确文本(I和l都设为I) iVBORw0KGgoAAAANSUhEUgAAA5gAAABUAQMAAADdxAqsAAAABGdBTUEAALGOfPtRkwAAACBjSFJNAAB6JQAAgIMAAPn/AACA6QAAdTAAAOpgAAA6mAAAF2+SX8VGAAAABIBMVEUAAAD///+I2Z/dAAAACXBIWXMAABJ0AAASdAHeZh94AAAFtkIEQVRo3u3YvW7cOBAH8BFYMIURurwigF5hyxSC+UouUywsLVzcY+RRwoUfwI9wBK5IGQJXWAszmvvPUNqVdu3LNfYBBy0MYyVR/PFjOKRN/P6f1VzN1VzN1VzN1VzN1fxvzLDxy5upId9Gv5Y7PzksS/h/WX/vf2UOjnk31ahmbLUB6SWzIye/67WdXochv3mwnGtcvWbSZJpEnGnRz8jkpFIzM45mQLGe2kCcqvKAOBiOBk9QE76SmcxMhNL3L5h4qT8zB5I+dHMzTCZ+JfKBRNAHxJ0Rq8OdNIQX5u5omnF2Bpg+nZmZjLzxgpmIImKGyfSdsFIagftM1dIMI6ZFyfiS2b9qxk2NukM1M9G50RyIXjPtaGaHuuT2wmwr6c3cpJkZstuPRZkfcTvgAqaUCHe+O8WQVnxp1pdmypjLI83+VTPhSV8j5tvwmomxzczfS3AjtA6pxfWj4QO+IqGMHA7MX5IRxUA8JD9wf1vMB10qT9rCWm5wH9VE02F6fmb+g3nPf53MAWb0iGPtJ5ocU4sGGwn5WMwDTDTEcu80oNLGo51pMmVZd1JbP5p4gg6q2TipwMg66U5mwIohm6maTEx35xA7mTxRqQ1mcEGXH+eNBAuWUDFrNVGWdcjFICc6zDA3WKVOFgOqq5emWZpk+6O5KybNzA5PjJox+wcJPIQ4mbVkr6NJZhCzFdMtzI+Ib5gYNpIIvzNISfhpxDSjafehIYWTbIHI22LKmjD5yuTPTs1o8jVSUSsTgICnnihf2YisY1HkaPZ062uTrmD2YmZDd/Y+XZn0sTEn8zf7ED0hYFJiCr6u1JTcZ2QeZEg5ikmTiRer3IB2JiDmXN66siCmnLBPXkykK9q6sHX76E302QXOo3mHjt3I95AGfUNNyVCUZTg0LbdBAkNMNAIp3vQOntInL22yJ9NOpIezcRFsaA3eFNMWU9ZdI9/3abAaIVM/TybSspWLqZ8nsy6mn5mpSi1YRI1JjUtisgmI/cjJ4WU1B5LAd/cpu+QxDamNmCksj8Zi37HBDegcSTtjO5CWcL2PMHcwa2mPm5mhimJiq4BZpy11xfSJY41gUDMX06gZxQwmfMEtjAwiPTiZhtGUTacr5u216T7UWLq0NKmKMrzomOnVpKOJfWk0QzGJPsGk0ZQkLSMjZnK6YNXsNXI7McI0WCYYxIV5M5mIsXNTJ2ZpXk1mtPvR/DKZcVvMsmG0k1nLbCzMBnHKCK6jWfPRHI8LuL5HOXIFzMaVGNoPxbz1VpYKVtLcrFjnU84HiBIve780W0x0Md3JrOPwz+ZuMItbDisSf0cT25oPM3O+Vpq6rE/MgsQt1oqaLSK9DIeaZjI/2VM/pe4bF7F+ynYVZ+YNNoVaTDnX4TB3Zu6KmWqpGDkBr5WccDQHa8r65Hh3MuU5rkPajmYY41ZiqJGNKJRsjwMkXuP52Faa+/bBh7A1tDV/pg9Ih8h9ut7FvHZV0NyHHYm6xIExN+6euKL0GSZSv6XBSB4KoUY1OJsY6t1jaHAWQBPme3ZDVZIcH+QUg5J3dMzxR5Nc2U3U1OwvWQW3SZJ0IjVruZB8K7udvCtbh+xIYtK5mYvZRqnBq6I72VZN5BmSFnXF7OhmNLGvIL8GoybBxHZp1WyITtIt0aULU9bnPuOnLsdj2rRydINzc+qnI59iSi/CtJfpkbY3rvQTh1unJfTMSdP+CbM3M/Mb88N3IkTcW4m3+CwHG/skKfswaLGfwiY95eCkgm8tJvZZnmAg5Rg1uK9aEEsU3T8wakId/HOQZddiwf3ALvD1ZOKDOz/uS4h+K3XJsemJZ59ngYd2asLp2aA/3/j8U1rL7VifFFmY2uJivuUnXpiDfWszLM0DNiLz1ma3NBPOA29u7s5M/J359Nbm46X5Tp+jqX/xvLOZ3+8/KOv/pFZzNVdzNVdzNVdzNVfz/2My/w0IEhI1v4hi9wAAAABJRU5ErkJggg==
将这个文本带入之前脚本的字符串变量a,再跑两次脚本,得到两组文本
然后在网站上在线分别将两组文本base64转图片(注意加上“data:image/png;base64,”的前缀),其中一个文本转为图片后得到flag
拿了个三血嘿嘿//