我正在尝试验证文件的签名。我按照以下说明生成证书：
// generate a private key with size of 2048 bits
openssl genrsa -out private_key.pem 2048
// derive a public key from the above private key
openssl rsa -in private_key.pem -out public_key.pem -outform PEM -pubout
// iOS will not import PEM encoded data so it needs to be converted to DER encoded data
openssl rsa -pubin -inform PEM -outform DER -in public_key.pem -out public_key.der
// generate a self-signed certificate for testing
openssl req -new -x509 -key private_key.pem -out test_cert.pem -days 1095
// show the content of the original certificate
openssl x509 -in test_cert.pem -text -noout
// convert the certificate to DER format
openssl x509 -in test_cert.pem -outform der -out test_cert.der
// show the content of the new certificate
openssl x509 -in test_cert.der -inform der -text -noout
我用的例子是这个链接 https://web.archive.org/web/20160330194058/www.codealias.info/technotes/openssl_rsa_sign_and_verify_howto对一些数据进行哈希处理并验证一切是否正常（我执行了步骤 2 - 5）。
现在我正在尝试将 .der 文件、签名文件和数据文件放入 Android 应用程序中，并基本上验证一切是否正常。我没有收到任何错误，但我没有出错。下面是我编写的代码：
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Base64;
import android.util.Log;
import android.widget.TextView;
import java.io.*;
import java.security.*;
import java.security.cert.CertificateFactory;
import java.security.cert.Certificate;
// Most of the below is taken from:
// http://www.herongyang.com/JDK/Digital-Signature-JcaVerify-Signature-Verification-Program.html
public class MyActivity extends Activity {
String input = Environment.getExternalStorageDirectory() + "/data.txt";
String signFile = Environment.getExternalStorageDirectory() + "/signature";
String signAlgo = "SHA1withRSA";
int keyFile = R.raw.test_cert_josh;
String TAG = "VERIFY";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView textView = (TextView) findViewById(R.id.textView);
try {
PublicKey pubKey = readPublicKey(keyFile);
byte[] sign = readSignature(signFile);
textView.setText(verify(input, signAlgo, sign, pubKey) + "");
} catch (Exception e) {
e.printStackTrace();
}
}
PublicKey readPublicKey(int cert_id) throws Exception {
InputStream in = MyActivity.this.getResources().openRawResource(cert_id);
byte[] buff = new byte[4000];
int bytesRead;
ByteArrayOutputStream out = new ByteArrayOutputStream();
while((bytesRead = in.read(buff)) != -1) {
out.write(buff, 0, bytesRead);
Log.i(TAG, "bytes read: " + bytesRead);
}
byte[] publicKeyBytes = out.toByteArray();
CertificateFactory cf = CertificateFactory.getInstance("X509");
Certificate cert = cf.generateCertificate(new ByteArrayInputStream(publicKeyBytes));
PublicKey pubKey = cert.getPublicKey();
Log.i(TAG, "Public Key Info: ");
Log.i(TAG, "Algorithm = " + pubKey.getAlgorithm());
Log.i(TAG, "toString = " + pubKey.toString());
return pubKey;
}
byte[] readSignature(String input) throws Exception {
FileInputStream signStream = new FileInputStream(input);
byte[] signBytes = new byte[signStream.available()];
signStream.read(signBytes);
signStream.close();
return signBytes;
}
boolean verify(String input, String algorithm, byte[] sign, PublicKey pubKey) throws Exception {
Signature sg = Signature.getInstance(algorithm);
sg.initVerify(pubKey);
Log.i(TAG, "Signature Object Info: ");
Log.i(TAG, "Algorithm = "+sg.getAlgorithm());
Log.i(TAG, "Provider = "+sg.getProvider());
FileInputStream in = new FileInputStream(input);
byte[] buff = new byte[in.available()];
in.read(buff);
sg.update(buff);
boolean ok = sg.verify(sign);
Log.i(TAG, "Verify Processing Info: ");
Log.i(TAG, "Verification result = "+ok);
return ok;
}
}
我读过的所有内容都表明我的代码是正确的。我认为有关获取公钥的部分是正确的，因为模数与实际 .der 文件中的模数相匹配。
请帮忙！
EDIT:我认为这与我读取签名文件或数据文件的方式有关。我很确定我正确地获取了有关公钥的所有信息，因为我打印了有关它的附加信息并且它与openssl 输出
EDIT根据下面 Nikolay 的建议，我尝试使用以下代码在 Android 应用程序中签署与我在 openssl 中登录的相同数据：
// testing code to sign it myself
// read the data file in
FileInputStream dataStream = new FileInputStream(input);
byte[] dataBytes = new byte[dataStream.available()];
dataStream.read(dataBytes);
dataStream.close();
// hash the data file, like i do with openssl
// per Nikolay's comments, this is not needed
MessageDigest digest = MessageDigest.getInstance("SHA-1");
// digest.update(dataBytes, 0, dataBytes.length);
// dataBytes = digest.digest();
Log.i(TAG, "data from file: " + new String(dataBytes));
// read the private key in
FileInputStream fis = new FileInputStream(Environment.getExternalStorageDirectory() + "/phaero/private_key.pem");
byte[] keyBytes = new byte[fis.available()];
fis.read(keyBytes);
fis.close();
// clean up the private key and decode it
String temp = new String(keyBytes);
Log.i(TAG, "private key: " + temp);
String privKeyPEM = temp.replace("-----BEGIN RSA PRIVATE KEY-----\n", "");
privKeyPEM = privKeyPEM.replace("-----END RSA PRIVATE KEY-----", "");
byte[] decoded = Base64.decode(privKeyPEM.getBytes(), Base64.DEFAULT);
// create the private key object from the private key data
PKCS8EncodedKeySpec private_spec = new PKCS8EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance("RSA");
PrivateKey privateKey = kf.generatePrivate(private_spec);
// set up for signing
Signature signer = Signature.getInstance(signAlgo);
signer.initSign(privateKey);
signer.update(dataBytes, 0, dataBytes.length);
// sign, and hash again so i can compare against openssl output
byte[] signed = signer.sign();
digest.update(signed, 0, signed.length);
Log.i(TAG, new BigInteger(1, digest.digest()).toString(16));
快速注意：在 Jelly Bean 中使用上述代码，您必须在创建 KeyFactory 时指定“BC”。
然后我对签名结果进行哈希处理，看看它是否与使用 openssl 生成的签名文件的哈希值相匹配，但它们不匹配..所以我不知道这意味着什么，但我知道这意味着什么！我假设在 openssl 中创建签名文件时需要指定某种附加选项？
EDIT:
根据下面 Nikolay 的评论，我将测试代码更新为不签名，但是在 java 中创建的签名的哈希值仍然与使用 openssl 创建的签名文件的哈希值不匹配...不知道出了什么问题，Java、OpenSSL 还是我。
