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From "Yuri Dolgov" <dolgov.g.y...@gmail.com>
Subject Re: [classlib][security]How to discard padding data after decryption.
Date Wed, 14 Nov 2007 15:23:07 GMT
Hello Leo,

For "no padding" modes there is no padding added to the data encrypted.
Though
you have to encrypt only data aligned to cipher block size.

Thanks,
Yuri

On 11/14/07, Leo Li <liyilei1979@gmail.com> wrote:
>
> Here is an exmple:
>
>     byte[] data = ...; // data encrypted with DES-CBC-CRC
>     byte[] keyBytes = ...;  // the DES key used to encrypt data.
>     final byte[] iv = new byte[]
>         { ( byte ) 0x00, ( byte ) 0x00, ( byte ) 0x00, ( byte ) 0x00, (
> byte
> ) 0x00, ( byte ) 0x00, ( byte ) 0x00,
>             ( byte ) 0x00 };
>     Cipher cipher = Cipher.getInstance( "DES/CBC/NoPadding" );
>     SecretKey key = new SecretKeySpec( keyBytes, "DES" );
>     AlgorithmParameterSpec paramSpec = new IvParameterSpec( iv );
>     cipher.init( Cipher.DECRYPT_MODE, key, paramSpec );
>     byte[] decryptedData = cipher.doFinal( data );
>
>     Has the decryptedData got here already discarded the padding bytes? If
> not, how to discard these data?
>
>    Is there somebody familar with this?
>    Thanks in advance.
>
> --
> Leo Li
> China Software Development Lab, IBM
>

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