使用 PEM 私钥对字符串进行签名

Question

我有一个PEM编码的私钥，我需要用它签署一个字符串。但是代码不断崩溃并出现异常：

java.security.spec.InvalidKeySpecException: java.lang.RuntimeException: error:0c0890ba:ASN.1 encoding routines:asn1_check_tlen:WRONG_TAG

密钥字符串：

-----BEGIN ENCRYPTED PRIVATE KEY-----
MIICxjBABgkqhkiG9w0BBQ0wMzAbBgkqhkiG9w0BBQwwDgQI4P/+9mJV6RwCAggA 
MBQGCCqGSIb3DQMHBAg/ZWGXeLHgeASCAoAhExhFxfcikmIKbFP0rgAlJuj1r999 
... and so on...
hlgzM2p71FdC6NDVyyxbit/IzbimtJyhkRwOAnZ98yqtXWUEOx2v7CcUqiU8dSLA 
K0PsaxNTUeUcQV+Z7yJk/8HxfE1ya3u2CgPXCZsWWmbxQG/+awE0eEnZ 
-----END ENCRYPTED PRIVATE KEY-----

我尝试了很多变体，查看了许多答案，但结果是一样的

编辑：在James K Polk的帮助下，我设法获得了私钥字节，但现在我得到了java.security.NoSuchAlgorithmException: SecretKeyFactory PBES2 implementation not found.修改的代码：

private String sign(String dataString, String pkString, String privateKeyPass) throws Exception {
pkString = pkString.replace("-----BEGIN ENCRYPTED PRIVATE KEY-----", "");
pkString = pkString.replace("-----END ENCRYPTED PRIVATE KEY-----", "");
pkString = pkString.replaceAll("\s+","");
byte[] privateKeyBytes = decryptPrivateKey(Base64.decode(pkString, Base64.DEFAULT), privateKeyPass);
KeyFactory kf = KeyFactory.getInstance("RSA");
PrivateKey privateKey = kf.generatePrivate(new PKCS8EncodedKeySpec(privateKeyBytes));
Signature instance = Signature.getInstance("SHA1withRSA");
instance.initSign(privateKey);
instance.update(dataString.getBytes(UTF_8));
return Base64.encodeToString(instance.sign(), Base64.DEFAULT);
}
public static byte[] decryptPrivateKey(byte[] key, String pass) throws Exception {
PBEKeySpec passKeySpec = new PBEKeySpec(pass.toCharArray());
EncryptedPrivateKeyInfo encryptedKey = new EncryptedPrivateKeyInfo(key);
Timber.w("encryptedKey.getAlgName(): %s", encryptedKey.getAlgName());
SecretKeyFactory keyFac = SecretKeyFactory.getInstance(encryptedKey.getAlgName());//PBES2
SecretKey passKey = keyFac.generateSecret(passKeySpec);
// Create PBE Cipher
Cipher pbeCipher = Cipher.getInstance(encryptedKey.getAlgName());
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.DECRYPT_MODE, passKey, encryptedKey.getAlgParameters());
// Decrypt the private key
return pbeCipher.doFinal(encryptedKey.getEncryptedData());
}

编辑：我最终使用了 http://commandlinefanatic.com/cgi-bin/showarticle.cgi?article=art050 类：

PrivateKey privateKey = KeyImport.readPrivateKeyFile(pkFileName, privateKeyPass);

我将keyString保存到一个文件中，然后将其提供给readPrivateKeyFile

Answer 1

您的私钥是根据PKCS#8加密的，因此您需要使用EncryptedPrivateKeyInfo类等。此堆栈溢出问题包含一个示例，演示如何检索它。我在下面把它变成了一个更完整的例子：

import javax.crypto.Cipher;
import javax.crypto.EncryptedPrivateKeyInfo;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.Base64;
import java.util.List;
public class Main {
private static byte [] pemFileToBytes(String filename) throws IOException {
// read in PEM file, throw away the begin and end lines
List<String> pemLines = Files.readAllLines(Paths.get(filename), StandardCharsets.US_ASCII);
pemLines.remove(0);
pemLines.remove(pemLines.size() - 1);
String pem = String.join("", pemLines);
// base64 decode and return the result.
return Base64.getDecoder().decode(pem);
}
private static PrivateKey parsePrivateKey (String filename, char [] password) throws Exception{
PBEKeySpec passKeySpec = new PBEKeySpec(password); //my password
EncryptedPrivateKeyInfo encryptedKey = new EncryptedPrivateKeyInfo(pemFileToBytes(filename));
SecretKeyFactory keyFac = SecretKeyFactory.getInstance(encryptedKey.getAlgName());
SecretKey passKey = keyFac.generateSecret(passKeySpec);
// Create PBE Cipher
Cipher pbeCipher = Cipher.getInstance(encryptedKey.getAlgName());
// Initialize PBE Cipher with key and parameters
pbeCipher.init(Cipher.DECRYPT_MODE, passKey, encryptedKey.getAlgParameters());
// Decrypt the private key
byte [] encodedPrivateKey = pbeCipher.doFinal(encryptedKey.getEncryptedData());
PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(encodedPrivateKey);
KeyFactory kf = KeyFactory.getInstance("RSA");
return kf.generatePrivate(privateKeySpec);
}
public static void main(String[] args) throws Exception {
PrivateKey pk = parsePrivateKey("x.pk8", "pass".toCharArray());
}
}

最后一行return new String(instance.sign(), UTF_8);没有任何意义，因为Signature.sign()返回一个字节数组，该数组不太可能是任何字符集中的有效字符串。如果必须将签名转换为字符串，则标准方法是对其进行base64编码。