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List:       bouncycastle-crypto-dev
Subject:    Re: [dev-crypto] PROBLEM WITH MESSAGE DIGEST CALCULATION
From:       David Hook <dgh () bund ! com ! au>
Date:       2007-05-20 1:39:42
Message-ID: 1179625182.3506.37.camel () echidna
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On Sat, 2007-05-19 at 15:14 +0530, Joyson Machado wrote:
> Dear All,
> 
>  
> 
> I am going through the source code of Boncy castle crypto API to
> understand the steps for calculating the Message Digest (Hash value).
> As I went through the code I feel, it is MimeBodyPart which takes the
> content with headers and calculates the Message Digest in BC. I was
> expecting the Message Digest will be calculated by
> CMSSignedDataStreamGenerator class.
> 
>  
> 
> Can any one help me to understand these below points.
> 
>  
> 
> Which class calculates the message digest in BC?

Usually there are two, although the second one is embedded in a
signature. You can find the end construction in
CMSSignedDataGenerator.SignerInf.toSignerInfo.

> 
> What is the input provided to calculate message digest (content +
> headers)?

Everything in the mime body part being signed. See
SMIMEGenerator.makeContentBodyPart for details.

> 
> What is the format of input content?
> 

It depends on the content-transfer encoding of the body part.

Regards,

David



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