base62 | Base62 monkeypatches Integer to add an Integer | Hashing library

I'm reading an online document that explains how to design a url shortening service. The website is https://www.educative.io/courses/grokking-the-system-design-interview .

In the section, Encoding actual URL, they said -> "We can compute a unique hash (e.g., MD5 or SHA256, etc.) of the given URL. The hash can then be encoded for displaying. This encoding could be base36 ([a-z ,0-9]) or base62 ([A-Z, a-z, 0-9]) and if we add ‘+’ and ‘/’ we can use Base64 encoding. A reasonable question would be, what should be the length of the short key? 6, 8, or 10 characters."

"If we use the MD5 algorithm as our hash function, it’ll produce a 128-bit hash value. After base64 encoding, we’ll get a string having more than 21 characters (since each base64 character encodes 6 bits of the hash value).Since we only have space for 8 characters per short key, how will we choose our key then? We can take the first 6 (or 8) letters for the key. This could result in key duplication, to resolve that, we can choose some other characters out of the encoding string or swap some characters."

I used online MD5 hash generator (http://onlinemd5.com/) and Base64 encoder (https://www.base64encode.org/) to verify the above. I used "www.yahoo.com" as the input string for MD5 hash and output is 1B03577ED104F16AADC00A639D33CB44 . Then I Base64 encoded it and got MUIwMzU3N0VEMTA0RjE2QUFEQzAwQTYzOUQzM0NCNDQ= with UTF-8 destination charset and Unix newline seperator.

Can anyone explain if I'm doing it correctly? I see the number of characters are way more than 21.

I want to encrypt and decrypt recursively any key which ends with id or _id.

It should loop through all the key inside passed array or object or array of objects to search for the key and encrypt it. Finally it will return encrypted data.

I tried below function, but it's not working.

I am creating a python script for base62 encoding. However, for some reason, my code doesn't produce the correct answer. Correct answer is LpuPe81bc2w, but i get LpuPe81bc0w. If you can review my code and see if I can do any different. Please let me know. I can't use pybase62.

I really want to know why my code doesn't work because I want to understand fundamental. Preferably

NO PyBASE62 and I am a beginner.

I'm trying to shorten UUID values (stored in DB as UUID, not string) to be embedded in URLs. I'm aware of Base64 for URL, but trying to see if I can make it without dash and underscore characters. So I would like to convert UUID to base62. After a lot of googling I found:

1. There's not a standard for this (something like RFC2045), am I right?

2. Most importantly there's no proper implementation for it. I found a lot of snippets on how to do it, but with some sort of note that "this is a naive implementation" or something. Is there a proper implementation (I don't mind the exact interpretation how the mapping should be done as long as it's done properly)?

3. There are some base classes in Apache Commons Codec and Guava which are extended for Base32 and Base64, but I didn't find it easy to extend it for Base62. Is it even possible to do it (considering the fact that the mapping is fundamentally different)?
   Thanks.

I can not reproduce this example although I have changed db name and password.Tree structure

My Docker container builds fine on OSX:

I have obtained following code to convert an Integer to a Base62 character of length 3. Is there a way I could reverse this to obtain back the initial Integer?

Example: Following code converts the Integer 238328 to "zzz" which is what I want. Is there a way I could use back "zzz" and get back the Integer 238328?

I found some code to encode a Base10-String with to a custom BaseString:

I have Clojure function generate-id.

Source code: