I have a string:
RP581147238IN which gets encoded as A3294Fc0Mb0V1Tb4aBK8rw==
and another string:
RP581147239IN which gets encoded as A3294Fc0Mb1BPqxRDrRXjQ==
But after spending a day, I still cannot figure out what is the encoding process.
The encoded string looks like its base64 encoded.
But when I decode it, it looks like:
base64.decodestring("A3294Fc0Mb0V1Tb4aBK8rw==")
\x03}\xbd\xe0W41\xbdA>\xacQ\x0e\xb4W\x8d
The base 64 decoded string now is looking like a zlib compressed string
I've tried to further use zlib decompression methods but none of them worked.
import zlib, base64
rt = 'A3294Fc0Mb1BPqxRDrRXjQ=='
for i in range(-50, 50):
try:
print(zlib.decompress(base64.decodestring(rt), i));
print("{} worked".format(i))
break
except:
pass
But that did not produce any results either.
Can anybody figure out what is the encoding process used here. #Nirlzr, I am looking at you for the heroic answer you provided in Reverse Engineer HTTP request.
The strings seem to be Base64 encoded and the underlying decoded data seems to be encrypted. Encrypted data can not be directly represented as a string and it is common the Base64 encode encrypted data when a string is required.
If this is the case you need to decrypt the decoded data and ignorer to accomplish that you would need the encryption key.
Note: In general it is not productive to compress such short items.
If you put your data strings side by side:
RP581147238IN A3294Fc0Mb0V1Tb4aBK8rw==
RP581147239IN A3294Fc0Mb1BPqxRDrRXjQ==
You can see that source strings have only character difference, but encoded version contains 12 different characters:
----------8-- ----------0V1Tb4aBK8rw--
----------9-- ----------1BPqxRDrRXjQ--
Encoded data has similar paddings at the end as base64, but definitely it is not base64. Probably crypted with some SHA-like algorithm. With the data you provided, I would say that it is not possible to reverse-engineer the encoding process. Probably more data would not help much either.
Related
I'm reading emails with imaplib, and found out that some email contents are encoded base64, and some 7bits.
I tried to decode it with 'Content-Transfer-Encoding' value.
But even more, some have 'Content-Transfer-Encoding' header in message object, whereas some have it in message.get_payload()[0].
I can deal with these some cases, but I think there can be more cases that I haven't found.
Is there any better way to decode email contents, no matter how they are encoded?
Thanks :)
when using get_payload(), I added decode=True option, so that it can automatically decode if needed. link
And then, isinstance(content, bytes) tells you whether you have to uni-decode or not.
The Scenario:
I'm reading about JSON web tokens at this link (https://medium.com/vandium-software/5-easy-steps-to-understanding-json-web-tokens-jwt-1164c0adfcec). It outline how to create a JSON web token, you create a header and a payload, and then create a signature using the following pseudocode:
data = base64urlEncode( header ) + “.” + base64urlEncode( payload )
hashedData = hash( data, secret )
signature = base64urlEncode( hashedData )
My Question:
Why does the pseudocode use base64urlEncode when creating data and signature?
Scope Of What I Understand So Far:
Base64 allows you to express binary data using text characters from the Base64 set of 64 text characters. This is usually used when you have a set of data that you want to pass through some channel that might misinterpret some of the characters, but would not misinterpret Base64 characters, so you encode it using Base64 so that the data won't get misinterpreted. Base64 URL encoding, on the other hand, is analogous to Base64 encoding except that you use only a subset of the Base64 character set that does not include characters that have special meaning in URLs, so that if you use the Base64 URL encoded string in a URL, its meaning won't get misinterpreted.
Assuming my understanding there is correct, I'm trying to understand why base64urlEncode() is used in computing data and signature in the pseudocode above. Is the signature of a JSON web token going to be used somewhere in a URL? If so, why is data base64urlEncoded as well before hashing. Why not just encode the signature? Is there something about the hash function that would require its data parameter to be Base64 URL encoded?
When using the OAuth Implicit Grant, JWTs may be transferred as part of URL fragments.
That is just an example, but I guess in general it was presumed that JWTs might be passed through URLs, so base64urlEncodeing them makes sense.
The first line of the IETF JWT standard abstract even says:
JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties.
(Note that the OAuth Implicit Grant is no longer recommended to be used.)
When a file is selected or dropped, is it automatically converted to Base64 encoding?
I need to be able to take files, convert them to strings then pass them into POST requests to our backend.
Is ng-file-upload already converting the file? Or is this something I need to manually do by calling either the:
Upload.base64DataUrl(files).then(function(urls){...});
or
Upload.dataUrl(file, boolean).then(function(url){...});
methods?
I can post the relevant code but this seems relatively straightforward. Thanks for the help!
I'm using the GMail API to retrieve an email contents. I am getting the following base64 encoded data for the body: http://hastebin.com/ovucoranam.md
But when I run it through a base64 decoder, it either returns an empty string (error) or something that resembles the HTML data but with a bunch of weird characters.
Help?
I'm not sure if you've solved it yet, but GmailGuy is correct. You need to convert the body to the Base64 RFC 4648 standard. The jist is you'll need to replace - with + and _ with /.
I've taken your original input and did the replacement: http://hastebin.com/ukanavudaz
And used base64decode.org to decode it, and it was fine.
You need to use URL (aka "web") safe base64 decoding alphabet (see rfc 4648), which it doesn't appear you're doing. Using the standard base64 alphabet may work sometimes but not always (2 of the characters are different).
Docs don't seem to consistently mention this important detail. Here's one where it does though:
https://developers.google.com/gmail/api/guides/drafts
Also, if your particular library doesn't support the "URL safe" alphabet then you can do string substitution on the string first ("-" with "+" and "_" with "/") and then do normal base64 decoding on it.
I had the same issue decoding the 'data' fields in the message object response from the Gmail API. The Google Ruby API library wasn't decoding the text correctly either. I found I needed to do a url-safe base64 decode:
#data = Base64.urlsafe_decode64(JSON.parse(#result.data.to_json)["payload"]["body"]["data"])
Hope that helps!
There is an example for python 2.x and 3.x:
decodedContents = base64.urlsafe_b64decode(payload["body"]["data"].encode('ASCII'))
If you only need to decode for displaying purposes, consider using atob to decode the messages in JavaScript frontend (see ref).
I found whilst playing with the API result, once I had drilled down to the body I was given an option to decode in the available methods.
val message = mService!!.users().messages().get(user, id).setFormat("full").execute()
println("Message snippet: " + message.snippet)
if(message.payload.mimeType == "text/plain"){
val body = message.payload.body.decodeData() // getValue("body")
Log.i("BODY", body.toString(Charset.defaultCharset()))
}
The result:-
com.example.quickstart I/BODY: ISOLATE NORMAL: 514471,Fap, South Point Rolleston, 55 Faringdon Boulevard , Rolleston, 30 May 2018 20:59:21
I coped the base64 test to a file (b64.txt), then base64-decoded it using base64 (from coreutils) with the -d option (see http://linux.die.net/man/1/base64) and I got text that was perfectly readable. The command I used was:
cat b64.txt | base64 -d
I have created code which takes a string from a text field and calls a encrypting method for doing encryption of that text using the base64 encoding scheme. But I don't have any idea how to create the decryption method for decrypting whatever value I am getting from the method.
Save yourself some trouble and download the NSData Base64 category.
Then you can encode or decode using a single line.