如何反哈希值或者知道如何生成随机数类似的公式

也不知道这个是不是哈希得来的，希望兄弟们可以帮忙看看，出出主意。

https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-07/1002_0953_20160802100400_0c37f9.jpg 

以上是一个图片链连， 1002_0953_20160802100400_0c37f9.jpg

1002 0953 是不变的，代表摄像头吧

20160802100400 代表 YYYYMMDDHHMMSS

0c37f9 是个随机生成的 6 位字符串或者哈希值，

现在如果我能够了解这个值是如何得来的，就可以直接去 AWS 下载图片了，兄弟们有没有高见？可以把时间戳和摄像头哈希成 6 位的字符么？我用的哈希都是比这个 6 位数长的，不好意思，对这个不熟。

API 文档在 这里

以下是 API 的输出，可以看到所以图片的链接都是有个随机数在后面的。

 "odata.metadata": "http://datamall2.mytransport.sg/ltaodataservice/$metadata#CameraImageSet", "value": [ { "CameraID": "1001", "Latitude": 1.29531332, "Longitude": 103.871146, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1001_1008_20160802101200_9d8b5b.jpg" }, { "CameraID": "1002", "Latitude": 1.319541067, "Longitude": 103.8785627, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1002_0953_20160802101200_36a753.jpg" }, { "CameraID": "1003", "Latitude": 1.323957439, "Longitude": 103.8728576, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1003_0953_20160802101000_93254d.jpg" }, { "CameraID": "1004", "Latitude": 1.319535712, "Longitude": 103.8750668, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1004_0953_20160802101201_b172d8.jpg" }, { "CameraID": "1005", "Latitude": 1.363519886, "Longitude": 103.905394, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1005_1008_20160802101201_9c9636.jpg" }, { "CameraID": "1006", "Latitude": 1.357098686, "Longitude": 103.902042, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1006_1003_20160802101001_74ae66.jpg" }, { "CameraID": "1501", "Latitude": 1.27414394350065, "Longitude": 103.851316802547, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1501_1003_20160802101201_09c088.jpg" }, { "CameraID": "1502", "Latitude": 1.27135090682664, "Longitude": 103.861828440597, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1502_1003_20160802101201_504789.jpg" }, { "CameraID": "1503", "Latitude": 1.27066408655104, "Longitude": 103.856977943394, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1503_1003_20160802101200_52cdb2.jpg" }, { "CameraID": "1504", "Latitude": 1.29409891409364, "Longitude": 103.876056196568, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1504_0938_20160802101201_37aa6b.jpg" }, { "CameraID": "1505", "Latitude": 1.2752977149006, "Longitude": 103.866390381759, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1505_1008_20160802101201_8d709f.jpg" }, { "CameraID": "1701", "Latitude": 1.323604823, "Longitude": 103.8587802, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1701_1006_20160802101300_46a943.jpg" }, { "CameraID": "1702", "Latitude": 1.34355015, "Longitude": 103.8601984, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1702_1009_20160802101300_66674d.jpg" }, { "CameraID": "1703", "Latitude": 1.32814722194857, "Longitude": 103.862203282048, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1703_1010_20160802101201_b2799f.jpg" }, { "CameraID": "1704", "Latitude": 1.28569398886979, "Longitude": 103.837524510188, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1704_1011_20160802101300_43bee7.jpg" }, { "CameraID": "1705", "Latitude": 1.375925022, "Longitude": 103.8587986, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1705_1011_20160802101300_0221c2.jpg" }, { "CameraID": "1706", "Latitude": 1.38861, "Longitude": 103.85806, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1706_1010_20160802101300_53ef7e.jpg" }, { "CameraID": "1707", "Latitude": 1.28036584335876, "Longitude": 103.830451146503, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1707_1010_20160802101300_96145f.jpg" }, { "CameraID": "1709", "Latitude": 1.31384231654635, "Longitude": 103.845603032574, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1709_1012_20160802101300_236a5c.jpg" }, { "CameraID": "1711", "Latitude": 1.35296, "Longitude": 103.85719, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/1711_1011_20160802101300_6509c5.jpg" }, { "CameraID": "2701", "Latitude": 1.447023728, "Longitude": 103.7716543, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/2701_1009_20160802101300_17b27a.jpg" }, { "CameraID": "2702", "Latitude": 1.445554109, "Longitude": 103.7683397, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/2702_1012_20160802101300_cebe1b.jpg" }, { "CameraID": "2703", "Latitude": 1.35047790791386, "Longitude": 103.791033581325, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/2703_1010_20160802101201_0645b0.jpg" }, { "CameraID": "2704", "Latitude": 1.429588536, "Longitude": 103.769311, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/2704_1008_20160802101202_c013c4.jpg" }, { "CameraID": "2705", "Latitude": 1.36728572, "Longitude": 103.7794698, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/2705_1010_20160802101201_b45a63.jpg" }, { "CameraID": "3702", "Latitude": 1.33831, "Longitude": 103.98032, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3702_1010_20160802101202_70004b.jpg" }, { "CameraID": "3704", "Latitude": 1.2958550156561, "Longitude": 103.880314665981, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3704_1010_20160802101201_ddf222.jpg" }, { "CameraI": "3705", "Latitude": 1.32743, "Longitude": 103.97383, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3705_1010_20160802101202_940482.jpg" }, { "CameraID": "3793", "Latitude": 1.309330837, "Longitude": 103.9350504, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3793_1010_20160802101201_0495a2.jpg" }, { "CameraID": "3795", "Latitude": 1.30145145166066, "Longitude": 103.910596320237, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3795_1010_20160802101202_9389b3.jpg" }, { "CameraID": "3796", "Latitude": 1.297512569, "Longitude": 103.8983019, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3796_1010_20160802101201_0671e8.jpg" }, { "CameraID": "3797", "Latitude": 1.29565733262976, "Longitude": 103.885283049309, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3797_1011_20160802101202_a8da2c.jpg" }, { "CameraID": "3798", "Latitude": 1.29158484, "Longitude": 103.8615987, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/3798_1010_20160802101201_c0e278.jpg" }, { "CameraID": "4701", "Latitude": 1.2871, "Longitude": 103.79633, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4701_1008_20160802101202_5f569e.jpg" }, { "CameraID": "4702", "Latitude": 1.27237, "Longitude": 103.8324, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4702_1010_20160802101201_525f4c.jpg" }, { "CameraID": "4703", "Latitude": 1.348697862, "Longitude": 103.6350413, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4703_1009_20160802101300_245a7e.jpg" }, { "CameraID": "4704", "Latitude": 1.27877, "Longitude": 103.82375, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4704_1009_20160802101201_5c9ee1.jpg" }, { "CameraID": "4705", "Latitude": 1.32618, "Longitude": 103.73028, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4705_1010_20160802101202_2c2111.jpg" }, { "CameraID": "4706", "Latitude": 1.29792, "Longitude": 103.78205, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4706_1010_20160802101202_17ab81.jpg" }, { "CameraID": "4707", "Latitude": 1.33344648135658, "Longitude": 103.652700847056, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4707_1009_20160802101203_c6fd1e.jpg" }, { "CameraID": "4708", "Latitude": 1.29939, "Longitude": 103.7799, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4708_1010_20160802101202_f1882b.jpg" }, { "CameraID": "4710", "Latitude": 1.32153, "Longitude": 103.75273, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4710_1012_20160802101300_2d8028.jpg" }, { "CameraID": "4712", "Latitude": 1.341244001, "Longitude": 103.6439134, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4712_1010_20160802101202_afb948.jpg" }, { "CameraID": "4713", "Latitude": 1.347645829, "Longitude": 103.6366955, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4713_1011_20160802101300_8bb9c7.jpg" }, { "CameraID": "4714", "Latitude": 1.31023, "Longitude": 103.76438, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4714_1009_20160802101203_690d16.jpg" }, { "CameraID": "4716", "Latitude": 1.32227, "Longitude": 103.67453, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4716_1010_20160802101203_0d7160.jpg" }, { "CameraID": "4798", "Latitude": 1.25999999687243, "Longitude": 103.823611110166, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4798_1011_20160802101204_f7538b.jpg" }, { "CameraID": "4799", "Latitude": 1.26027777363278, "Longitude": 103.823888890049, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/4799_1010_20160802101204_db2424.jpg" }, { "CameraID": "5794", "Latitude": 1.3309693, "Longitude": 103.9168616, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/5794_1010_20160802101204_7725e4.jpg" }, { "CameraID": "5795", "Latitude": 1.326024822, "Longitude": 103.905625, "ImageLink": "https://s3-ap-southeast-1.amazonaws.com/mtpdm/2016-08-02/10-15/5795_1010_20160802101204_a61365.jpg" }