Hello!
I have the same problem.
Encoded (with JAVA) public key in a file and no chance to import the
key with crypto++
Please help
On 5 Sep. 2003, 19:53, Scott Barnhart <[EMAIL PROTECTED]>
wrote:
> Hi,
>
> I am trying to use CryptoPP 5.1 to decode files encoded with the Java crypto
> classes using Diffie-Hellman keys and DESede encryption (CBC mode, PKCS5
> padding). The problem I can not figure out at this point is how to load a
> 1024-bit Diffie-Hellman public or private key from a file, where the public
> key is in X509 format, and the private key is PKCS#8 format. The DH::Agree()
> method wants byte* arguments for the keys, in (I assume) an un-encoded
> format. I am getting totally lost in how to use all the different template
> classes and arguments to template classes to construct what I want. All the
> DH sample code shows generating keys, and then using those same keys
> immediately to do the DH agreement. But I can't find any code which shows
> how to load DH keys from a file system.
>
> Can someone please show me some code or some pointers in the right direction
> on how to do this? I have used CryptoPP for some other stuff
> (DefaultEncryptorWithMAC), and I understand Sources, Sinks, and
> Transformations pretty well, but I can NOT figure this out. Anyhelpwould be
> greatly appreciated.
>
> Here is the Java code I use to generate and save the DH keys:
>
> DHParameterSpec dhSkipParamSpec = new DHParameterSpec(skip1024Modulus,
> skip1024Base);
> KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("DH");
> keyPairGen.initialize(dhSkipParamSpec);
> KeyPair keyPair = keyPairGen.generateKeyPair();
>
> writeKey(keyPair.getPublic(), "Public.bin");
> writeKey(keyPair.getPrivate(), "Private.bin");
>
> private void writeKey(Key key, String strName) throws Exception
> {
> FileOutputStream fKey = new FileOutputStream(strName);
> fKey.write(key.getEncoded()); // java getEncoded() returns X509
> format for public key, PKCS#8 for private
> fKey.close();
> }
>
> The java code to encode looks like:
>
> private void run(String strPriFile, String strPubFile, String
> strFileToEncode) throws Exception
> {
> KeyFactory facDH = KeyFactory.getInstance("DH");
> KeySpec pubKeySpec = new X509EncodedKeySpec(getRawKey(strPubFile));
> KeySpec priKeySpec = new PKCS8EncodedKeySpec(getRawKey(strPriFile));
>
> PublicKey pubKey = facDH.generatePublic(pubKeySpec);
> PrivateKey priKey = facDH.generatePrivate(priKeySpec);
>
> KeyAgreement keyAgree = KeyAgreement.getInstance("DH");
> keyAgree.init(priKey);
> keyAgree.doPhase(pubKey, true);
> SecretKey keySecret = keyAgree.generateSecret("DESede"); //
> Transforms the DH agreed secret value into a 168-bit 3DES key.
>
> Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");
> cipher.init(Cipher.ENCRYPT_MODE, keySecret);
>
> FileInputStream fIn = new FileInputStream(strFileToEncode);
> DataOutputStream fOut = new DataOutputStream(new
> FileOutputStream(strFileToEncode + ".enc"));
>
> byte[] iv = cipher.getIV(); // get the initialization vector
> fOut.write(iv); // write IV
>
> // Read from the input and write to the encrypting output stream
> byte[] buffer = new byte[BUFSIZE];
> int bytesRead;
> while((bytesRead = fIn.read(buffer)) != -1)
> {
> fOut.write(cipher.update(buffer, 0, bytesRead));
> }
> fOut.write(cipher.doFinal());
> fOut.close();
> fIn.close();
> }
>
> private byte[] getRawKey(String strFile) throws Exception
> {
> File keyfile = new File(strFile);
> DataInputStream in = new DataInputStream(new
> FileInputStream(keyfile));
> byte[] rawkey = new byte[(int)keyfile.length()];
> in.readFully(rawkey);
> in.close();
> return rawkey;
> }
>
> Thanks,
> Scott Barnhart
> [EMAIL PROTECTED]
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