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Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function?

Cross-posted to 2 groups.

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On 19.06.18 22:18, Lothar Kimmeringer wrote:
> Karl.Frank wrote:
>
>> The amount of byte to read is exactly defined by
>>
>>     int BuffSize = System.in.available();
>>     byte[] pwByte = new byte[BuffSize];
>>     System.in.read(pwByte, 0, BuffSize);
>>
>> How would the program read more byte than necessary?
>
> InputStream.available only returns the number of bytes that
> can be read without blocking. Dependent on how the data ends
> up there there still might be data left to read that you
> missed because of that.
>
> What you're doing here is a common programming error.
>
>
> Cheers, Lothar

Well, well, well. The posted listing is just a short test program in
order to figure out why the results of the Java function were wrong.
It clearly does not expext a huge file being passed over by stdin.

Obviously in a program that need to handle large scale data one would
read in the data byte in chunks and process them subsequently like in
this short snipped


---------------------------------------8<----------

   int BuffSize = 8192;

   byte[] inByte  = new byte[BuffSize];
   byte[] outByte = new byte[BuffSize];

   int inB, outB, bufferRead;

   System.in.flush();
   System.out.flush();

   while ((bufferRead = System.in.read(inByte, 0, BuffSize)) != -1) {
     for (int i=0; i<bufferRead; i++){
       /*
         do something useful here
         for example XOR the byte

         inB  = (int)inByte[i];
         outB = (inB ^ *some CSPRNG byte output*) & 0xff;
         outByte[i] = (byte)outB;

         or similar...
       */
     }
     System.out.write(outByte, 0, bufferRead);
   }

   System.in.flush();
   System.out.flush();

   System.in.close();
   System.out.close();

--------------------------------------->8----------

So nothing to be worried about in regards of any unprocessed data left ;-)

Cheers,
Karl


-- 
cHNiMUBACG0HAAAAAAAAAAAAAABIZVbDdKVM0w1kM9vxQHw+bkLxsY/Z0czY0uv8/Ks6WULxJVua
zjvpoYvtEwDVhP7RGTCBVlzZ+VBWPHg5rqmKWvtzsuVmMSDxAIS6Db6YhtzT+RStzoG9ForBcG8k
G97Q3Jml/aBun8Kyf+XOBHpl5gNW4YqhiM0=

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Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? "Karl.Frank" <Karl.Frank@Freecx.co.uk> - 2018-05-15 23:37 +0200
  Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? "Karl.Frank" <Karl.Frank@Freecx.co.uk> - 2018-05-16 15:58 +0200
  Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? Robert Klemme <shortcutter@googlemail.com> - 2018-06-18 18:41 +0200
    Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-06-18 13:33 -0700
    Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? "Karl.Frank" <Karl.Frank@Freecx.co.uk> - 2018-06-19 12:54 +0200
      Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? Lothar Kimmeringer <news201705@kimmeringer.de> - 2018-06-19 22:18 +0200
        Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? Robert Klemme <shortcutter@googlemail.com> - 2018-06-19 23:20 +0200
        Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? "Karl.Frank" <Karl.Frank@Freecx.co.uk> - 2018-06-19 23:23 +0200
      Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? Robert Klemme <shortcutter@googlemail.com> - 2018-06-19 23:15 +0200
        Re: Why is Java 7 converting the Password toCharArray instead of Byte in it's PBKDF2 function? "Karl.Frank" <Karl.Frank@Freecx.co.uk> - 2018-06-20 00:03 +0200

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