cleaned security sensitive data after usage

[dmytro-sheyko]

#1362 Crypt32Util.cryptProtectData leaves security sensitive information in memory
#1362

[dbwiddis]

Looks good from my end. This is probably worthy of a change log entry.

[dmytro-sheyko]

Slightly corrected previous commit:

1. CryptUnprotectData accepts null as pointer to description. We don't use it here, so I got rid of it.
2. Clear result byte array when LocalFree fails and hence CryptProtectData/CryptUnprotectData throws exception

[matthiasblaesing]

Also looks good to me. I agree with @dbwiddis though, this warrants an entry in the CHANGES.md file in the Bug Fixes section. For the synopsis I think something like:

Clear security sensitive data after usage in c.s.j.p.win32.Crypt32Util#cryptUnprotectData and #cryptUnprotectData.

As a rule of thumb: Changes that affect users should have an entry in the CHANGES.md- it basicly answers the question: "Why should I bother to update?".

[dmytro-sheyko]

Ok. I will change the commit message and also will try to write unit test for the issue (based on the program that demonstrates the problem).
And, just make it precise, may/should I add an entry in the CHANGES.md as well?

[dbwiddis]

Yes, the suggested blurb above should be in CHANGES.md in the Bug Fixes section, following the same format as the other entries.

[matthiasblaesing]

Looks good to me. Thank you.