Re: [GNU Crypto] GNU Crypto and OpenSSL

[Ben]

Thanks a bunch for pointing me in the right direction on this.  I fixed
up my code and thought I had it down, but now I am having another
problem.  Only the first 8 bytes (1 block) of my data is being
encrypted, the rest is just 0's.  I have 16 bytes total, and CBC mode is
supposed to encrypt multiples of 8 bytes right?  Here is my encryption
function:

  public byte[] encPayload(byte[] data, String keyStr) {
    byte[] encData = new byte[data.length];
    byte[] ivec = new byte[8];
    Map attrib = new HashMap();

    /* Set ivec to all 0's */
    for(int i = 0; i < ivec.length; i++)
      ivec[i] = 0;

    IMode blowfish_cbc = ModeFactory.getInstance(Registry.CBC_MODE,
      Registry.BLOWFISH_CIPHER, 8);
    attrib.put(IMode.IV, ivec); 
    attrib.put(IMode.KEY_MATERIAL, keyStr.getBytes()); 
    attrib.put(IMode.STATE, new Integer(IMode.ENCRYPTION));
    try {
      blowfish_cbc.init(attrib);
    } 
    catch (InvalidKeyException e) {
      System.out.println("ERROR: "+e.toString());
      System.exit(1);
    }
    blowfish_cbc.update(data, 0, encData, 0);
    return encData;
  }

What am I doing wrong here?
Thanks again,
Ben

On Sun, 2004-01-04 at 00:16, Casey Marshall wrote:
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> >>>>> "Ben" == Ben  <address@hidden> writes:
> 
> Ben> Hi, I am trying to write a Java program that exchanges
> Ben> Blowfish-encrypted data with a C program.  The C program uses the
> Ben> OpenSSL libraries (BF_cbc_encrypt() specifically) to do the
> Ben> encryption/decryption, and the Java program is using the GNU
> Ben> Crypto Blowfish class.  It isn't working.  I am thinking this
> Ben> might be because of the initialization vector.  BF_cbc_encrypt
> Ben> requires an initialization vector, which I have set to 0, but I
> Ben> can't find a way to set this or even see that it exists in GNU
> Ben> Crypto.  Is it possible to make these two libraries work
> Ben> together?
> 
> You need to use the mode API for CBC. The cipher API is a low-level,
> ECB-only one.
> 
> Your Java application would look something like this:
> 
> ===
> import gnu.crypto.Registry;
> import gnu.crypto.IMode;
> import gnu.crypto.ModeFactory;
> 
> ...
> 
> Map attrib = ...;
> IMode blowfish_cbc = ModeFactory.getInstance(Registry.CBC_MODE,
>   Registry.BLOWFISH_CIPHER, 8);
> 
> attrib.put(IMode.IV, your_iv); // byte[]
> attrib.put(IMode.KEY_MATERIAL, your_key); // byte[]
> attrib.put(IMode.STATE, new Integer(IMode.ENCRYPTION));
> 
> blowfish_cbc.init(attrib);
> 
> // in and out are byte[], offsets are int.
> blowfish_cbc.update(in, in_offset, out, out_offset);
> 
> ...
> ===
> 
> Also note that our CBC mode does not allow the input buffer to be the
> same as the output buffer. This will probably change eventually.
> 
> Cheers.
> 
> - -- 
> Casey Marshall || address@hidden
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-- 
Ben <address@hidden>