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Creating Chrome Extensions (.crx) without Chrome and with Java - crxmake for Java
package de.devsurf.chrome.extensions;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
public class CrxWriter {
public static final String ALGORITHMN_ENCRYPT = "RSA";
public static final String ALGORITHMN_SIGNATURE = "SHA1withRSA";
public static final String CRX_BEGINNING = "Cr24";
public static final byte[] CRX_BEGINNING_BYTES = CRX_BEGINNING.getBytes();
public static final byte[] VERSION = new byte[]{2,0,0,0};
public void create(OutputStream crxFile, InputStream content, PrivateKey privateKey, PublicKey publicKey) throws Exception{
crxFile.write(CRX_BEGINNING_BYTES);
crxFile.write(VERSION);
byte[] publicKeyBytes = publicKey.getEncoded();
crxFile.write(new byte[]{(byte)publicKeyBytes.length,0,0,0});
byte[] zip = readBytes(content, 8192, true);
byte[] signature = createSignature(zip, privateKey);
crxFile.write(new byte[]{(byte)signature.length,0,0,0});
crxFile.write(publicKeyBytes);
crxFile.write(signature);
crxFile.write(zip);
crxFile.flush();
crxFile.close();
}
protected byte[] createSignature(byte[] dataToSign, PrivateKey privateKey) throws NoSuchAlgorithmException, InvalidKeyException, SignatureException{
Signature signer = Signature.getInstance(ALGORITHMN_SIGNATURE);
signer.initSign(privateKey); // PKCS#8 is preferred
signer.update(dataToSign);
return signer.sign();
}
protected byte[] readBytes(InputStream in, int bufferSize, boolean forceClose) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream(bufferSize);
try {
byte[] buffer = new byte[bufferSize];
for (;;) {
int len = in.read(buffer);
if (len < 0) {
break;
}
baos.write(buffer, 0, len);
}
baos.flush();
} finally {
if (forceClose) {
try {
in.close();
} catch (Exception e) {
// ignore
}
try {
baos.close();
} catch (Exception e) {
// ignore
}
}
}
return baos.toByteArray();
}
}
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