[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [iaik-jce] Question about ConstructorSignedAndEnvelopedDataStream(java.io.InputStream is,AlgorithmID contentEA)



The constructor does not process the data. It generates the temporary
content encryption key and setups the cipher for encryption. This may last
longer the first time due ro random number generator initialization.You may
initially create a new thread to initiate the Random generator. The data
encryption actually is performed during the encoding phase - initiated by
finally calling the writeTo method - where the data is piped through a
cipher stream.

Dieter Bratko

----- Original Message -----
From: Betty <ahyan@doramail.com>
To: <iaik-jce@iaik.tu-graz.ac.at>
Cc: <cutepang@net.polyu.edu.hk>
Sent: Monday, August 30, 1999 6:40 AM
Subject: [iaik-jce] Question about
ConstructorSignedAndEnvelopedDataStream(java.io.InputStream is,AlgorithmID
contentEA)


> Dear all,
>
> I'm going to ask about the Constructor
> SignedAndEnvelopedDataStream(java.io.InputStream is,
>                              AlgorithmID contentEA)
> --------------------------------------------------------------
> The input parameter that I pass as follows:
> is = an InputStream with carrying 50 bytes PlainText
> contentEA = AlgorithmID.des_EDE3_CBC
> When I start my program....    (with using Celeron 433 computer)
>     In the first time, it takes 120 seconds to create the above
>                        new object.
>     In the second time, I create such kind of object again.
>     It takes 70 seconds.
> ---------------------------------------------------------------
> The input parameter that I pass as follows:
> is = an InputStream with carrying 25000 bytes PlainText
> contentEA = AlgorithmID.des_EDE3_CBC
> When I start my program....    (with using Celeron 433 computer)
>     In the first time, it takes 120 seconds to create the above
>                        new object.
>     In the second time, I create such kind of object again.
>     It takes 70 seconds.
> ---------------------------------------------------------------
> I would like to ask:
> 1) Why there is a different between the first time and second time.
> 2) Why does it take the same time to create a new object with
>    a large different size of PlainText.
> 3) In the class SignedAndEnvelopedDataStream, which method is
>    performing the encryption of PlainText. Alternatively,
>    is it performed in the Constructor?
>
> Regards
> Betty Pang
>
>
> Get your free email from http://www.doramail.com with 10 Megs of free
diskspace
>
>
> powered by OutBlaze
> --
> Mailinglist-archive at
http://jcewww.iaik.tu-graz.ac.at/mailarchive/iaik-jce/maillist.html
>
> To unsubscribe send an email to listserv@iaik.tu-graz.ac.at with the
folowing content: UNSUBSCRIBE iaik-jce
>
>
>


smime.p7s