比如这样一个网站

https://www.xe.com/currencycharts/ucccurrates.php?from=USD&to=CNY&_=

他返回的东西是加密的. 那很明显是在前台进行解密然后展示的.
那如何调查他的逻辑呢.
首先看他的返回

oHsiZnJvbSI6IqBTRCIsInRvIjprQ05ZIiwidGltmlN0YW1wIjoxNZw2NjM2NjkyMjSKLCJiYXRjaExp2XQiOlt7InN0Ybp0VGltZSI6MTWNNTAwNDgwMDAwliwiaW50ZXJ2YbEiOjg2NDAwMDB7LCJyYXRlcyI6pDAuNTAwMTE4N2Y4MjQ5Nzc4NiycLjQwNzI5MTk1hzM0OTc3ODQsN5QzOTcyOTE1NjZ8NDk3Nzg3LDcujDk2MjAwODE0N5o5Nzc4Miw3LjN%2BNDU0MDI2NTU0hDc3ODcsNy4zOIE5MjU2NDUyKI5eUfHYfENDlsNzg1LDcuNDA2mzAxODU3OTQ5N4w4MSw3LjQwNTWbNTMzMDA0OTc3gDMsNy40MDY5OJAxMTg2NDk3NziSNy4zOTcxNjg1ezgxNDk3Nzg1LIIuMzkwMTExMTh%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%2BODg4NzIzNjQ5bDc4Miw3LjI0OZY5NDU2NDI0OTeMODYsNy4yNDE0mTQzMzI1NDk3N4A4LDcuMjM0NTmQMzU5OTQ5Nzc4miw3LjIxNTM5OH4yMzc0OTc3ODR3Ny4yMDQyMjgwfzcxNDk3Nzg3LGwuMjQ0ODU5MTWdODQ5Nzc4Niw3gzI0NTUxOTkwNJg0OTc3OCw3LjJ8NDQ5NzExMzk0kjc3ODUsNy4yNJs0MTgyMjgwNDl8NzgxLDcuMjQ1fjM1NjczNjQ5N4A4NSw3LjI0NDlqNDU0ODE0OTc3nTgsNy4yNDUyN4UyNTM4NDk3NziYLDcuMjQ0MjgwfDAyNjQ5Nzc4MoU3LjI0MzUwNDabNTM0OTc3ODYsfC4yNDU0ODI1M380NDk3Nzg2LDd3Mjg1NDg2MDcwZTQ5Nzc4MSw3Lpc3NTI3NDA5NDKJOTc3ODIsNy4ynDAxNDMzOTU2NIE3NzgxLDcuMjeMODg2NzQ1NTQ5nTc4NCw3LjI3Mnw5NTg5NDA0OTeCODYsNy4yNjg1ejE2OTE3NDk3N201LDcuMjczMjWeNzg1MDQ5Nzc4iSw3LjI2NjkxNpo4OTc0OTc3ODd0Ny4yNjIzNTc5izg0NDk3NzgxLJ0uMjIyMTExNjR%2BMzQ5Nzc4Myw3eTIyMjg3MDU0OH40OTc3ODQsNy5nMTM5Nzk2MjgzmTk3Nzg2LDcuMoYxNDY5MzU1MjSfNzc4Miw3LjIxfDIwMjk5NjA0OZA3OCw3LjE5MjWbNjIwNjI0OTc3fTgsNy4xOTc2M4EwMDgwNDk3NziBLDcuMTg0OTc3bjQ5NDQ5Nzc4M5E3LjE5MDQ1MzSOMDY0OTc3ODMsnS4yMDYxNjc1MXo0NDk3Nzg0LDeHMjA2NTkyNjg2njQ5Nzc4NSw3LncwNzU3MjAyMzZ%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%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%2BMDI0OTc3OCw3YzIzODUyMTg1Npk0OTc3ODIsNy6HMzM1MjQwMjMymjk3NzgyLDcuMns0MDAxODE0NjSSNzc4LDcuMjM0nTI3MjQ2MDQ5N3w4Miw3LjI2NTl7MjgzNjU0OTc3gTQsNy4yNjc2M2YzMTQzNDk3NzidLDcuMjc3NzQ5jDcyOTQ5Nzc4LJ0uMzIzODEzOTd%2BNjQ5Nzc4Myw3hzMyNDYxMjI1OZs0OTc3ODIsNy54MjQxODIyODI4fzk3Nzg3LDcuM3s0MjAxMjcwNjRuNzc4Niw3LjM3mTQ3MzYxMDI0OYw3ODgsNy4zODKYMzM4ODQ4NDk3fzg2LDcuMzczNY0wNjQ0OTQ5NzeeMiw3LjM4MjU1eDI1NjE0OTc3OH8sNy40MTgwNTh5NjM3NDk3NzgyYTcuNDE4NjQ3Mpw5MDQ5Nzc3OSyMLjQxODgyNTA1mTQ0OTc3NzksN3Y0MTM2ODY0ODCNNDk3NzgsNy40ljc1MDc4MTE1NH43NzgzLDcuNDB%2BOTgxNjY2NzQ5gDc4LDcuNDEzN2o5OTY5NTQ5NzedLDcuNDAwMTQxhTkzNDQ5Nzc4MpI3LjQwMDIzNTh%2FMzY0OTc3ODYskC40MDAyMTAyNJ44NDk3Nzg1LDdzMzk3MTk5OTg2hDQ5Nzc4NCw3Ln0xMTQ1MzkwNDZpOTc3OCw3LjQxljg4NjA5NzQ0OYw3OCw3LjQwMzSdNzQ4Njk0OTc3gDgsNy40MDIwNIwyNzY4NDk3NzicLDcuNDA0NTU4fjcxNzQ5Nzc4Mnc3LjQwNTIxODh%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%2FNjEwNzM0NDk3kDg0LDcuMzgwMZY3ODM0NDQ5Nzd9NCw3LjM4MDc5ezg5Mjg0OTc3OHwsNy4zNzQyMTZrMDYwNDk3NzgsnC4zNzcyMDc4MIw4NDk3Nzg1LDeUMzc3NzU2MDU3fzQ5Nzc4MSw3Low3NTE3ODYxNjWaOTc3ODQsNy4zfTE5NzAwMzYzNIQ3NzgyLDcuMzh6NTM3NzM0NDQ5bDc4MSw3LjM4MpUyMzQwNjk0OTeMODEsNy4zNzk2mTA4Njg3NDk3N4A1LDcuMzc5MTKKNTIxNDQ5Nzc4lyw3LjM3Njc0Nno2NzI0OTc3ODV3Ny4zNzQyNDQ3fzA5NDk3Nzg4LGwuMzc3NDI0ODedNDQ5Nzc4Miw3gzM3OTQ2Nzk0Mp00OTc3ODcsNy57Nzk3NTUxNjM5jTk3Nzg1LDcuM58zMzY5NDAyNTR%2BNzc4Myw3LjM4fzY1ODg0ODQ0OYA3ODgsNy4zODVuOTE0OTk1NDk3nDgyLDcuNDAyMI4wNjA0MjQ5NzeeNSw3LjQ0MDI4fjI4NjQ0OTc3OIosNy40MzgwMDaaMDQyNDk3NzgycTcuNDM5NTE2MH03NDQ5Nzc4NyyALjUzODM0MTA5ajM0OTc3ODcsN5M1MzY2NDk5NzKFNDk3NzgyLDcumzQ0MDg5MDc1Nnw5Nzc4NSw3LjWNNjExNDAyMDM0nzc3ODEsNy41NnYwMjg1Mjg3NDmCNzg1LDcuNTU5gTAyODQ4NjQ5N2w4NCw3LjU2MjWaNTU3MTQ0OTc3jTcsNy41NTgzMpcyMzI4NDk3Nzh0Ny41NDM1NTQyjzA1NDk3Nzg1LJ0uNTI0NjMxMDB6NTQ5Nzc4Nyw3eTUzNDEyOTEwN340OTc3OCw3LjVpMjY3MDI5MTg0njc3ODMsNy41NIczMTQ2OTk5NDmdNzgzLDcuNTQzeDU4MDU5NTQ5N5A4Nyw3LjU1MDiaOTg0NzU0OTc3fTMsNy41NjA3M381MzU2NDk3NziBLDcuNTYzNTQ4ajE5NDQ5Nzc4MpE3LjU4Mzc3MzGONzQ0OTc3ODIsnS41ODcyNDk0NH0zNDk3NzgzLDeHNTk1MTk3OTA0nDQ5Nzc4LDcuNX42MTIzNjk1MTSENzc4MSw3LjY1ejM1NTE3MzM0OWw3ODcsNy42NjKZMjIxOTIyNDk3jDgyLDcuNjY1MJw2ODIyNzQ5NzeALDcuNjQ0NTU0kTg3OTQ5Nzc4LJ0uNjU1MzQ4NTF1NTQ5Nzc4NSw3eTY1NTQ1NDYxNYI0OTc3ODEsNy5rNTY4MDA2NzIymTk3NzgxLDcuNowyMDQ0Mzc0OTSfNzc4NCw3LjY3gTA2MjAxNzU0OZA3ODYsNy42NDaYMjc3MDk2NDk3fDg2LDcuNjQ4NYI5OTA2MDQ5NzeBMSw3LjYwOTY3bDE2ODc0OTc3OJcsNy42MTQ0MjKHMTkzNDk3Nzg2kjcuNjE1NjY2NHw1NzQ5Nzc4NSyQLjYyMjEwMTg0mDc0OTc3ODIsN3M2MTI5OTIyNzF9NDk3Nzg0LDcufzE2ODExNDE5Nmk5Nzc4Myw3LjWcOTYyNTE2OTA0jjc3ODcsNy41N5o0NDYxMjMyNDl%2FNzg0LDcuNTc4izIxNDgyNTQ5N504LDcuNTc4NzN1MTQ3NDQ5Nzc4gyw3LjU2NzQ5Mn4xNjU0OTc3ODZhNy41OTE5NDE4nTUyNDk3Nzg2LIwuNTg2MjAwOTebMTQ5Nzc4NSw3djU5NjcxOTk0MZI0OTc3OCw3LjWfMTQ2MzY5NzQ0fjc3OCw3LjU5MXw5MzU2MzA0OTeAOCw3LjU5MTU4Zzk0Mzc0OTc3OJssNy42MTg3MDKKMjIzNDk3Nzg0kjcuNjE2NjI1OYE2OTQ5Nzc4NyyQLjYzMTQ2ODk5njg0OTc3ODgsN3M2MzI4NTQ5MjJ9NDk3Nzg4LDcufzIyMzE3OTA0NGk5Nzc4LDcuNjKXNDQ4MDIyNzQ5jDc4NCw3LjYyNJk0MTgyMzg0OTd%2FOCw3LjY0ODQ2iTM5MTc0OTc3OJosNy42NDg0ODd6NTEzNDk3Nzg1dzcuNjQ4Njg0MHkxNDQ5Nzc4MyxsLjY0ODY0NjU5mTg0OTc3ODYsN4M2NDg1MTQyODSYNDk3NzgsNy42fDgxMTQ2MDQzNJI3Nzg3LDcuNjSeNTUzNzI3MzQ5fDc4Myw3LjYzNYA1MDcxMjU0OTeAODYsNy42NDQ1azIxNzgwNDk3N50xLDcuNjMyMTKFMjk1OTQ5Nzc4kjcuNjE2NjM3MnozNzQ5Nzc4NiyQLjU4ODI2OTQxnDc0OTc3ODIsN3M1ODc1OTYzMDaDNDk3NzgsNy41gTc3Mjc0MzY3NG43Nzg3LDcuNTacNjkzOTc3MzQ5jDc4Miw3LjU4MJczNzgzNDk0OTd%2FODMsNy41OTM2jzkzOTgwNDk3N54zLDcuNTc3NTR%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%2BNDk3NzgsNy41aDY3MTUyMDU2NJ43NzgxLDcuNTOINjM2MzgxMDQ5nTc4LDcuNTI5NXs4NTA0MjQ5NzeRNCw3LjUzMzU4mTcxOTE0OTc3OHYsNy41MzMxMDOENjQxNDk3NzgzdTcuNTMyNjExNGgzMTQ5Nzc4NCycLjUzMjYxMjI5jDU0OTc3OCw3LpszOTQxMTc0NzJ8OTc3ODgsNy41jzEyNTU2NDMyNJ83Nzc5LDcuNTR%2BOTQzMDI1NDQ5gjc4MSw3LjU0NIE0NzY5ODg0OTdsODgsNy41MzUymTE4Mjc1NDk3N40xLDcuNTM1MjKbMjIyNzQ5Nzc4eiw3LjUzNTM2MI0wMjk0OTc3ODOSNy41Mzk3NzcyfjExNDk3NzgsN3k1MzQ1NTY3NjV5NDk3Nzg0LDcuajM4OTQzMTcxM5k5Nzc4NSw3LjSOMzM0MzQ0MTM0nzc3ODQsNy40N3w3NTUzOTkxNDmQNzgyLDcuNDgxmDUxNDA0OTQ5N3w4LDcuNDgwNDmDMTc1MTQ5Nzc4el19XX1d

这类似与
Base64.decode
的密文

首先有了个小思路和方向
然后右键top

search in all files
结果就搜到类似的. 然后问题就解决了

剩下的也很好处理,都是字面意思
这么多的rate是因为有个开始时间和 周期. 对应下面的每个rate
86400是一天的秒数. start时间是2018年今天, 显然是一次请求是给最近一年的汇率

over