Bug 18524 - Base64 encoding bug
Summary: Base64 encoding bug
Status: RESOLVED FIXED
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: marcos.henrich
URL:
Depends on:
Blocks:
 
Reported: 2014-03-21 16:39 UTC by Craig
Modified: 2014-09-02 12:04 UTC (History)
2 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Craig 2014-03-21 16:39:21 UTC
The code below produces an incorrect result for variables s and b.  The results do not match what is produced in standard .NET.

  byte[] b = Convert.FromBase64String("UBo3FDjs8DabAbDhVwzqqQ==");
  string s = Encoding.UTF8.GetString(b) + "WQ3cgGvwGI10jSZoQQTTGsdk3nFH2xTVUvOXIV1JVM0=";
  b = Encoding.UTF8.GetBytes(s);
  s = Convert.ToBase64String(b);
  b = Convert.FromBase64String(s);

Expected Result:
  s = UBo3FDjvv73vv70277+9Ae+/ve+/vVcM77+9V1EzY2dHdndHSTEwalNab1FRVFRHc2RrM25GSDJ4VFZVdk9YSVYxSlZNMD0=
  b = 71

Actual Result:
  s = UBo3FDjvv73vv70277+9Ae+/ve+/vVcM77+977+9V1EzY2dHdndHSTEwalNab1FRVFRHc2RrM25GSDJ4VFZVdk9YSVYxSlZNMD0=
  b = 74
Comment 1 Craig 2014-03-21 16:43:59 UTC
The above code may actually be a problem with UTF8 Encoding rather than Base64 encoding.  Regardless, there seems to be a problem.
Comment 2 Craig 2014-03-21 17:09:21 UTC
This may be part of my problem, although I still wonder why it produces a different result than .NET:

"Not every byte sequence represents an Unicode string encoded in UTF-8 or UTF-16.

Not every Unicode string represents a byte sequence encoded in Base64."
Comment 3 marcos.henrich 2014-09-02 11:40:03 UTC
Hi Craig,

Thank you for the detailed bug report.

The pull request for this issue can be found in the link below.
https://github.com/mono/mono/pull/1251
Comment 4 marcos.henrich 2014-09-02 12:04:07 UTC
Fixed in master b5fcd926f8ee870e107cf534c1f9592586b8a0e9.
https://github.com/mono/mono/commit/b5fcd926f8ee870e107cf534c1f9592586b8a0e9