Parsing encrypted PKCS#8 encoded pem file programatically

I am having trouble figuring out how to properly read a private key of a pem file. I have gone through different topics on stackoverflow, but I couldn’t find the solution for it. What I want to achieve is reading an encrypted private key in pkcs#8 encoding file from a classpath and load it as a key-entry in a in memory keystore. Below is an example private key which I try to parse, the password is secret. It is purely created for sharing here, so it is not a private key which is used on a production machine.

I created it from a p12 file with the following command: openssl pkcs12 -in key-pair.p12 -out key-pair.pem

Valid example (throw-away) key-pair

-----BEGIN ENCRYPTED PRIVATE KEY-----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-----END ENCRYPTED PRIVATE KEY-----

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

I know BouncyCastle is able to parse it, but I want to avoid using additional libraries. So I am wondering if it is possible with just plain jdk or with some other lightweight libraries.

I am already able to parse private key with the following header/footer:

-----BEGIN PRIVATE KEY-----
           *
-----END PRIVATE KEY-----

and

-----BEGIN RSA PRIVATE KEY-----
           *
-----END RSA PRIVATE KEY-----

I already use the following snippet to accomplish that:

import com.hierynomus.asn1.ASN1InputStream;
import com.hierynomus.asn1.encodingrules.der.DERDecoder;
import com.hierynomus.asn1.types.ASN1Object;
import com.hierynomus.asn1.types.constructed.ASN1Sequence;
import com.hierynomus.asn1.types.primitive.ASN1Integer;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPrivateCrtKeySpec;
import java.util.Base64;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.UUID;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

class App {

    private static final String KEYSTORE_TYPE = "PKCS12";
    private static final String KEY_FACTORY_ALGORITHM = "RSA";
    private static final String CERTIFICATE_TYPE = "X.509";

    private static final Pattern CERTIFICATE_PATTERN = Pattern.compile("-----BEGIN CERTIFICATE-----(.*?)-----END CERTIFICATE-----", Pattern.DOTALL);
    private static final Pattern PRIVATE_KEY_PATTERN = Pattern.compile("-----BEGIN PRIVATE KEY-----(.*?)-----END PRIVATE KEY-----", Pattern.DOTALL);
    private static final Pattern ENCRYPTED_PRIVATE_KEY_PATTERN = Pattern.compile("-----BEGIN ENCRYPTED PRIVATE KEY-----(.*?)-----END ENCRYPTED PRIVATE KEY-----", Pattern.DOTALL);
    private static final Pattern RSA_PRIVATE_KEY_PATTERN = Pattern.compile("-----BEGIN RSA PRIVATE KEY-----(.*?)-----END RSA PRIVATE KEY-----", Pattern.DOTALL);

    private static final String NEW_LINE = "n";
    private static final String EMPTY = "";

    public static void main(String[] args) throws CertificateException, NoSuchAlgorithmException, KeyStoreException, IOException, InvalidKeySpecException {
        String privateKeyContent = "";
        String certificateContent = "";

        PrivateKey privateKey = parsePrivateKey(privateKeyContent);
        Certificate[] certificates = parseCertificate(certificateContent).values()
                .toArray(new Certificate[]{});

        KeyStore keyStore = createEmptyKeyStore();
        keyStore.setKeyEntry("client", privateKey, null, certificates);
    }

    private static KeyStore createEmptyKeyStore() throws KeyStoreException, IOException, NoSuchAlgorithmException, CertificateException {
        KeyStore keyStore = KeyStore.getInstance(KEYSTORE_TYPE);
        keyStore.load(null, null);
        return keyStore;
    }

    private static PrivateKey parsePrivateKey(String identityContent) throws NoSuchAlgorithmException, InvalidKeySpecException, IOException {
        KeySpec keySpec = null;

        Matcher privateKeyMatcher = PRIVATE_KEY_PATTERN.matcher(identityContent);
        if (privateKeyMatcher.find()) {
            String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
            keySpec = new PKCS8EncodedKeySpec(decodedPrivateKeyContent);
        }

        privateKeyMatcher = RSA_PRIVATE_KEY_PATTERN.matcher(identityContent);
        if (privateKeyMatcher.find()) {
            String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
            keySpec = getKeySpecFromAsn1StructuredData(decodedPrivateKeyContent);
        }

        privateKeyMatcher = ENCRYPTED_PRIVATE_KEY_PATTERN.matcher(identityContent);
        if (privateKeyMatcher.find()) {
            String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
            keySpec = null; //TODO
        }

        Objects.requireNonNull(keySpec);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM);
        return keyFactory.generatePrivate(keySpec);
    }

    private static KeySpec getKeySpecFromAsn1StructuredData(byte[] decodedPrivateKeyContent) throws IOException {
        try(ByteArrayInputStream privateKeyAsInputStream = new ByteArrayInputStream(decodedPrivateKeyContent)) {
            ASN1InputStream stream = new ASN1InputStream(new DERDecoder(), privateKeyAsInputStream);
            ASN1Sequence asn1Sequence = stream.readObject();

            if (asn1Sequence.getValue().size() < 9) {
                throw new RuntimeException("Parsed key content doesn't have the minimum required sequence size of 9");
            }

            BigInteger modulus = extractIntValueFrom(asn1Sequence.get(1));
            BigInteger publicExponent = extractIntValueFrom(asn1Sequence.get(2));
            BigInteger privateExponent = extractIntValueFrom(asn1Sequence.get(3));
            BigInteger primeP = extractIntValueFrom(asn1Sequence.get(4));
            BigInteger primeQ = extractIntValueFrom(asn1Sequence.get(5));
            BigInteger primeExponentP = extractIntValueFrom(asn1Sequence.get(6));
            BigInteger primeExponentQ = extractIntValueFrom(asn1Sequence.get(7));
            BigInteger crtCoefficient = extractIntValueFrom(asn1Sequence.get(8));

            return new RSAPrivateCrtKeySpec(
                    modulus, publicExponent, privateExponent,
                    primeP, primeQ, primeExponentP, primeExponentQ, crtCoefficient
            );
        }
    }

    private static BigInteger extractIntValueFrom(ASN1Object<?> asn1Object) {
        if (asn1Object instanceof ASN1Integer) {
            return ((ASN1Integer) asn1Object).getValue();
        } else {
            throw new RuntimeException(String.format(
                    "Unable to parse the provided value of the object type [%s]. The type should be an instance of [%s]",
                    asn1Object.getClass().getName(), ASN1Integer.class.getName())
            );
        }
    }

    private static Map<String, Certificate> parseCertificate(String certificateContent) throws IOException, CertificateException {
        Map<String, Certificate> certificates = new HashMap<>();
        Matcher certificateMatcher = CERTIFICATE_PATTERN.matcher(certificateContent);

        while (certificateMatcher.find()) {
            String sanitizedCertificate = certificateMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedCertificate = Base64.getDecoder().decode(sanitizedCertificate);
            try(ByteArrayInputStream certificateAsInputStream = new ByteArrayInputStream(decodedCertificate)) {
                CertificateFactory certificateFactory = CertificateFactory.getInstance(CERTIFICATE_TYPE);
                Certificate certificate = certificateFactory.generateCertificate(certificateAsInputStream);
                certificates.put(UUID.randomUUID().toString(), certificate);
            }
        }

        return certificates;
    }

}

I also am required to handle asn.1 encoded private key. I could use BouncyCastle, but again I wanted to avoid it because I am curious for alternatives. I got inspired from this topic: https://stackoverflow.com/a/42733858/6777695 but DerInputStream and DerValue aren’t accessible anymore from jdk 11 onwards. And the sun packages should be avoided… So I discovered asn-one java library to parse asn.1 encoded private key, and it works quite well.

I have shared my full snippet of handling the other cases, so it will be easier to try out when someone wants to help me.

From the following article: ASN.1 key structures in DER and PEM I learned that a private key having the following header/footer: -----BEGIN ENCRYPTED PRIVATE KEY----- * -----END ENCRYPTED PRIVATE KEY----- is also an asn.1 encoded private key with the following structure:

EncryptedPrivateKeyInfo ::= SEQUENCE {
  encryptionAlgorithm  EncryptionAlgorithmIdentifier,
  encryptedData        EncryptedData
}

EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier

EncryptedData ::= OCTET STRING

I also tried the answers provided here How to read a password encrypted key with java? but those also didn’t work. However I am not quite sure how to parse it correctly to a java object and load it as a KeySpec. So any help is welcome!

======> Updated progress at 12-09-2020 based on the input of dave_thompson_085

Matcher privateKeyMatcher = Pattern.compile("-----BEGIN ENCRYPTED PRIVATE KEY-----(.*?)-----END ENCRYPTED PRIVATE KEY-----", Pattern.DOTALL)
        .matcher(identityContent);

if (privateKeyMatcher.find()) {
    String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
    byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
    try (ByteArrayInputStream privateKeyAsInputStream = new ByteArrayInputStream(decodedPrivateKeyContent)) {
        ASN1InputStream stream = new ASN1InputStream(new DERDecoder(), privateKeyAsInputStream);
        ASN1Sequence asn1Sequence = stream.readObject();

        ASN1OctetString privateKeyAsOctetString = (ASN1OctetString) asn1Sequence.get(1);
        ASN1OctetString saltAsOctetString = (ASN1OctetString) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(0)).get(1)).get(0);
        ASN1OctetString initializationVectorAsOctec = ((ASN1OctetString) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(1)).get(1));
        ASN1Integer iterationCount = (ASN1Integer) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(0)).get(1)).get(1);

        IvParameterSpec ivParameterSpec = new IvParameterSpec(initializationVectorAsOctec.getValue());

        SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2withHmacSHA1");
        EncryptedPrivateKeyInfo encryptedPrivateKeyInfo = new EncryptedPrivateKeyInfo(secretKeyFactory.getAlgorithm(), privateKeyAsOctetString.getValue());

        int keyLength = encryptedPrivateKeyInfo.getEncoded().length;
        PBEKeySpec pbeKeySpec = new PBEKeySpec(keyPassword, saltAsOctetString.getValue(), iterationCount.getValue().intValue(), keyLength);

        Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding/");

        SecretKey secretKey = secretKeyFactory.generateSecret(pbeKeySpec);

        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);
        PKCS8EncodedKeySpec keySpec = encryptedPrivateKeyInfo.getKeySpec(cipher);
    }
}

Results into the following exception: java.security.InvalidKeyException: Wrong algorithm: DESede or TripleDES required on the statement cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);

======> Updated progress at 13-09-2020 based on the input of Michael Fehr

Matcher privateKeyMatcher = Pattern.compile("-----BEGIN ENCRYPTED PRIVATE KEY-----(.*?)-----END ENCRYPTED PRIVATE KEY-----", Pattern.DOTALL)
        .matcher(identityContent);

if (privateKeyMatcher.find()) {
    String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
    byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
    try (ByteArrayInputStream privateKeyAsInputStream = new ByteArrayInputStream(decodedPrivateKeyContent)) {
        ASN1InputStream stream = new ASN1InputStream(new DERDecoder(), privateKeyAsInputStream);
        ASN1Sequence asn1Sequence = stream.readObject();

        ASN1OctetString privateKeyAsOctetString = (ASN1OctetString) asn1Sequence.get(1);
        ASN1OctetString saltAsOctetString = (ASN1OctetString) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(0)).get(1)).get(0);
        ASN1OctetString initializationVectorAsOctec = ((ASN1OctetString) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(1)).get(1));
        ASN1Integer iterationCount = (ASN1Integer) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(0)).get(1)).get(1);

        IvParameterSpec ivParameterSpec = new IvParameterSpec(initializationVectorAsOctec.getValue());

        SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2withHmacSHA1");
        EncryptedPrivateKeyInfo encryptedPrivateKeyInfo = new EncryptedPrivateKeyInfo(secretKeyFactory.getAlgorithm(), privateKeyAsOctetString.getValue());

        int keyLength = 24 * 8;
        PBEKeySpec pbeKeySpec = new PBEKeySpec(keyPassword, saltAsOctetString.getValue(), iterationCount.getValue().intValue(), keyLength);

        Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding/");

        SecretKey secretKeyPbkdf = secretKeyFactory.generateSecret(pbeKeySpec);
        SecretKey secretKey = new SecretKeySpec(secretKeyPbkdf.getEncoded(), "DESede");

        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);
        PKCS8EncodedKeySpec keySpec = encryptedPrivateKeyInfo.getKeySpec(cipher);
    }
}

Answer

Your edited code gives an error “java.security.InvalidKeyException: Wrong key size” and that’s because you “read” the keyLength with this line:

int keyLength = encryptedPrivateKeyInfo.getEncoded().length;

With the given private key the length would be 1247 bits and that is not an allowed TripleDES length. You can fix it to (hardcoded):

int keyLength = 24 * 8;

Now we get a keyLength of 192 bit = 24 byte and that’s ok for an TripleDES-key but we receive a new error:

java.security.InvalidKeyException: Wrong algorithm: DESede or TripleDES required

The reason for this behavior is the following line (commented out) that can get fixed with the 2 additional lines:

// SecretKey secretKey = secretKeyFactory.generateSecret(pbeKeySpec); // ### old routine
SecretKey secretKeyPbkdf = secretKeyFactory.generateSecret(pbeKeySpec); // ### new
SecretKey secretKey = new SecretKeySpec(secretKeyPbkdf.getEncoded(), "DESede"); // ### new

Now your code is successfully running and print outs the private key and the certificate:

original keyLength:  1247
fixed keyLength(bit): 192

privateKey:
SunRsaSign RSA private CRT key, 2048 bits
  params: null
  modulus: 18998199686208613730227071552042680566660281525162377778227794768879762338654464000476266705180956908841709177555966832423085875590556580445428066261332223955361646420713402269532603328557674453787190302285379571808527818182992417461094551685532849252957724361115461909983939654809533488667032982867230996411860328826589806804115764031480737011900431983025490936659008858316889367140757195359233313370592669605576636360123189540118611655293825465309125578750878878980002346272931570343463549347548711194000065166346537274382220211242975801253306067862461345994215674963367480607539333468674983712264803816027753559737
  private exponent: 2470690692670644289832084636740463653655882622624760758103597888447170520657826825702415751838767348735186037205082706146786714644526202528897926495648786865000645626802269367582073915029633022103975204027927584273373553784482725392082470421529769049284506228997163157587212073758970565083984956787424047216319298607371397767542633302071090323391531162434678662485530085857362259661656308472034152915312425224731842425134593468185574918070451135641322780271191791839285884885643517240131520070881951542294552185519522325857178404160441369354693465035929601010771762928436963178293113507661955562266846499005032897533

number of certificates: 1

certificate: 0 data:
[
[
  Version: V3
  Subject: CN=Hakan, OU=Amsterdam, O=Thunderberry, C=NL
  Signature Algorithm: SHA256withRSA, OID = 1.2.840.113549.1.1.11

  Key:  Sun RSA public key, 2048 bits
  params: null
  modulus: 18998199686208613730227071552042680566660281525162377778227794768879762338654464000476266705180956908841709177555966832423085875590556580445428066261332223955361646420713402269532603328557674453787190302285379571808527818182992417461094551685532849252957724361115461909983939654809533488667032982867230996411860328826589806804115764031480737011900431983025490936659008858316889367140757195359233313370592669605576636360123189540118611655293825465309125578750878878980002346272931570343463549347548711194000065166346537274382220211242975801253306067862461345994215674963367480607539333468674983712264803816027753559737
  public exponent: 65537
  Validity: [From: Mon Aug 31 10:07:39 CEST 2020,
               To: Thu Aug 29 10:07:39 CEST 2030]
  Issuer: CN=Hakan, OU=Amsterdam, O=Thunderberry, C=NL
  SerialNumber: [    5671c8dd]

Certificate Extensions: 2
[1]: ObjectId: 2.5.29.17 Criticality=true
SubjectAlternativeName [
  DNSName: localhost
  IPAddress: 127.0.0.1
]

[2]: ObjectId: 2.5.29.14 Criticality=false
SubjectKeyIdentifier [
KeyIdentifier [
0000: 78 53 EC 04 E0 A1 55 45   22 C8 25 C4 3F F5 89 40  xS....UE".%.?..@
0010: 51 07 A8 03                                        Q...
]
]

]
  Algorithm: [SHA256withRSA]
  Signature:
0000: 85 55 87 FC 28 19 D1 93   66 4D F8 85 00 E9 D6 75  .U..(...fM.....u
0010: A6 55 69 AE EF 00 53 D3   D9 86 D7 BA F9 58 60 84  .Ui...S......X`.
0020: 65 AE ED 01 FF 39 F6 31   FC 26 9F 95 B6 A3 50 AA  e....9.1.&....P.
0030: A0 1B A1 C9 F1 2B 92 41   78 69 13 35 BD DB 88 8A  .....+.Axi.5....
0040: B5 23 95 C1 F8 F9 C1 57   AD 5D A0 B6 59 DF 79 64  .#.....W.]..Y.yd
0050: E0 FE C2 49 99 8C E4 25   31 9E 38 8A 91 94 1D 47  ...I...%1.8....G
0060: 28 2A A8 78 D0 AB CA 49   1C B2 29 04 09 0D 67 0A  (*.x...I..)...g.
0070: AA F5 A8 B8 7D 0D 7B 14   81 65 56 E7 B6 16 AA F3  .........eV.....
0080: F5 3F CC 4E 3B 6F C9 F6   C8 4C 07 A9 4E 85 FB 69  .?.N;o...L..N..i
0090: 6B 0A EA 67 68 4D 1B C7   EA 30 A8 D5 56 E5 29 14  k..ghM...0..V.).
00A0: 13 51 F9 63 83 43 FA D1   46 DA 9A EA E5 36 57 C6  .Q.c.C..F....6W.
00B0: 8E 39 9C 75 40 95 24 4D   D3 7B E9 83 82 B8 61 13  .9.u@.$M......a.
00C0: ED E7 5E BE 3A 5D 6D 15   DD 7B E1 D0 37 A9 9B 4F  ..^.:]m.....7..O
00D0: D3 8B C5 26 47 3B 46 90   AC 3C 83 98 D8 69 69 51  ...&G;F..<...iiQ
00E0: EE 42 7F CA B5 83 56 09   9E FC 5C A2 BC C2 D5 67  .B....V.......g
00F0: 7E 59 9F A8 4F DC F7 13   B5 9F F1 1C 56 F2 C2 76  .Y..O.......V..v

]

Here is the full code that is running on Open Java 11:

import com.hierynomus.asn1.ASN1InputStream;
import com.hierynomus.asn1.encodingrules.der.DERDecoder;
import com.hierynomus.asn1.types.ASN1Object;
import com.hierynomus.asn1.types.constructed.ASN1Sequence;
import com.hierynomus.asn1.types.primitive.ASN1Integer;
import com.hierynomus.asn1.types.string.ASN1OctetString;

import javax.crypto.*;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.math.BigInteger;
import java.security.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPrivateCrtKeySpec;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
// https://mvnrepository.com/artifact/com.hierynomus/asn-one/0.4.0
// additionally you need https://mvnrepository.com/artifact/org.slf4j/slf4j-api/1.7.30
// and https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12/1.7.30
// https://mvnrepository.com/artifact/org.eclipse.equinox/org.apache.log4j/1.2.13.v200706111418

class MainOrg3 {

    private static final String KEYSTORE_TYPE = "PKCS12";
    private static final String KEY_FACTORY_ALGORITHM = "RSA";
    private static final String CERTIFICATE_TYPE = "X.509";

    private static final Pattern CERTIFICATE_PATTERN = Pattern.compile("-----BEGIN CERTIFICATE-----(.*?)-----END CERTIFICATE-----", Pattern.DOTALL);
    private static final Pattern PRIVATE_KEY_PATTERN = Pattern.compile("-----BEGIN PRIVATE KEY-----(.*?)-----END PRIVATE KEY-----", Pattern.DOTALL);
    private static final Pattern ENCRYPTED_PRIVATE_KEY_PATTERN = Pattern.compile("-----BEGIN ENCRYPTED PRIVATE KEY-----(.*?)-----END ENCRYPTED PRIVATE KEY-----", Pattern.DOTALL);
    private static final Pattern RSA_PRIVATE_KEY_PATTERN = Pattern.compile("-----BEGIN RSA PRIVATE KEY-----(.*?)-----END RSA PRIVATE KEY-----", Pattern.DOTALL);

    private static final String NEW_LINE = "n";
    private static final String EMPTY = "";

    static char[] keyPassword = "secret".toCharArray();

    public static void main(String[] args) throws CertificateException, NoSuchAlgorithmException, KeyStoreException, IOException, InvalidKeySpecException {
        String privateKeyContent = "-----BEGIN ENCRYPTED PRIVATE KEY-----n" +
                "MIIFDjBABgkqhkiG9w0BBQ0wMzAbBgkqhkiG9w0BBQwwDgQI9/FSBonUacYCAggAn" +
                "MBQGCCqGSIb3DQMHBAidGkS8wYhOpwSCBMi8JaSYOKudMNNFRpzL7QMIZgFtzDayn" +
                "MmOroy3lW34dOa7dusqDl4d2gklKcHCpbEaTYxm5aQJ1LuiOdGtFy7HwxOvKU5xzn" +
                "4qsJoeBIpE0eCTKjQW7/I38DzLXx2wUURqhMWOtFsWZEyR5Dqok3N9mIKKKBXAFGn" +
                "AwNjlTRW2LyPSttiIUGN01lthjifMWoLTWB1aSGOmGeJRBdSZeqZ15xKneR4H5jan" +
                "yE88YcpOHCDKMIxi6ZVoKs7jDQhu8bBKqS8NsYyh1AlP9QkvWNal36jWSzhqYNzkn" +
                "NRWUOZngfkdbMALVfRtbrC215jHGWVwosPIIs8rkoarRv8s6QWS1Rg3YfQ3qgcRfn" +
                "s7hkDFKJf3TUXr+askfamV5hc300ZG64+ldX1YxWXY8Vd/wIvHAc/YE/lTyCgYrYn" +
                "19Am6MNBfp8/kXvzKj+PizB8oNDO4S8sSShEEzOQ5a/+MTC6bqB0DLWYGUqRbjLcn" +
                "PyYTC2C4i9Agx/GeGVE3c1UdtXiwwnt2XUn7Y1YGqABk0xGIY4J1NFTbSOxKl9hOn" +
                "arwopAFrZU5nsjjFzv1DJvhfQWnYX18kPSKNHDlia019M118qZ8ERwD9tH8ix9Fan" +
                "R2tQdxn1aRGmvXSw+zFkbWD8aWs9n/B+QN1yllJqVoWypOld1yj+fVYYnYOtV1gKn" +
                "eiygrtrh3JJCvLbEQl4nOgJM3PlEtfBHSaunehIXQMD1z/NDUqgBYjuDPyqRxJeHn" +
                "Va5k72Nds5PeySKJJnICB3nZKjqgfLhNUrXa1SAQ4vqr0Ik/Lu9P7T+B1XiYwuUTn" +
                "a20+bxi/x89ZZqwp3jnDuHup7XcO1MtqsoOKP/JgkjVMesb8Q1W8i2dXzg+l4gkkn" +
                "l1ipreEGtT1YfFTq0DFelz6CjZFLDlGGeGWob94sW94DWTW0nsLPhQWEnwW1CcyJn" +
                "oJbJdDEgdiIbRJoABDkTuVXLwTlgzHSHh6zeJvNvcojI7UI3nWYCVYvD3kwghXiPn" +
                "67sKGL3ug7PFDqLia46AudGY7CFh4+wpxyH+fidLC3FMdkDBA6xR6mGgEjRLXR9Mn" +
                "TnJ/eSYP7eqYZeKn9EarcI7v1zM2IG0/PDQCetiI0ABiHpdKyRQuuiEavp3xC5Vin" +
                "h7UmJNYt8Zsz3rwqAQ4FR2+Su5R34OOdRmxTaYLe96PXTpLcLef5TkYixSY7Tzgdn" +
                "PMyRxRPrywklUEFe4KK/KOcdolxybfsIsxQnupLAMEsO7/Cs7mouNHISK51haDRcn" +
                "vNbKQ5E4xOq1U4ThW5dHR29cGZillfmMzj05ZQh3ZX2TQJP45ahFET3v9kInWCwQn" +
                "8atqclVPOSnASsJZ0PxjYgKZuY8QWYM6zpfWyWnfu/CHhWbRS/qX8T1ow2SMyPBLn" +
                "CQbZ+MhcdP0IrjoXhDFQsns16i/BPK5TTVqtEC2ywDf5P4/BOEZkySG9YNOd6THpn" +
                "VA/dVPafzmLy3ltqH+jG8ZH2+RtWx7kwBjiDWs5cF33BFrPS7AZlzMzZoCHLXD/rn" +
                "T/SmisybUKHMqri0x0RHeIByW0hogSByWiyIn8POabDzJV6Df9nQPziDGcSsvWfGn" +
                "7q+hizh6+nnXOY+GZx3ptwg9mA9R4QyCiFNQradOaXSPxyEL2IC77/srFfVEIaU4n" +
                "SRo=n" +
                "-----END ENCRYPTED PRIVATE KEY-----";

        String certificateContent = "-----BEGIN CERTIFICATE-----n" +
                "MIIDTjCCAjagAwIBAgIEVnHI3TANBgkqhkiG9w0BAQsFADBIMQswCQYDVQQGEwJOn" +
                "TDEVMBMGA1UEChMMVGh1bmRlcmJlcnJ5MRIwEAYDVQQLEwlBbXN0ZXJkYW0xDjAMn" +
                "BgNVBAMTBUhha2FuMB4XDTIwMDgzMTA4MDczOVoXDTMwMDgyOTA4MDczOVowSDELn" +
                "MAkGA1UEBhMCTkwxFTATBgNVBAoTDFRodW5kZXJiZXJyeTESMBAGA1UECxMJQW1zn" +
                "dGVyZGFtMQ4wDAYDVQQDEwVIYWthbjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCn" +
                "AQoCggEBAJZ+pqirEqEk4k1ow8vryld79oCO4P/1y+v60CkLpS2MpeHE3BogTr7gn" +
                "WWP5HdHBMU5l8yT5tXuyVZZqgyzo0q2Sdm7GGrNunHf6Z8vPQFu69sQC1utDM9u8n" +
                "ZFKiKsTNJ+5QS6KsOtlACyhaLoaPAWVjtvueMjVwmM9hfv/Gq6VyyuBm2x1C4HTjn" +
                "zPCLHE2G1D13EJaWsvyZLGSbl0GGXZGPhaDd/vnw5TW36mvNTWW+37ZIEk4kXANan" +
                "FUNsJemm8HjB/PzHs3/SXGxuD8NKobg3+cNXYwAz2s2DI0W6Xw2g5bbrMQAdBRvnn" +
                "9/kNftMymDORw3RGwDM2ld4zQfIkNrkCAwEAAaNAMD4wHQYDVR0OBBYEFHhT7ATgn" +
                "oVVFIsglxD/1iUBRB6gDMB0GA1UdEQEB/wQTMBGCCWxvY2FsaG9zdIcEfwAAATANn" +
                "BgkqhkiG9w0BAQsFAAOCAQEAhVWH/CgZ0ZNmTfiFAOnWdaZVaa7vAFPT2YbXuvlYn" +
                "YIRlru0B/zn2Mfwmn5W2o1CqoBuhyfErkkF4aRM1vduIirUjlcH4+cFXrV2gtlnfn" +
                "eWTg/sJJmYzkJTGeOIqRlB1HKCqoeNCrykkcsikECQ1nCqr1qLh9DXsUgWVW57YWn" +
                "qvP1P8xOO2/J9shMB6lOhftpawrqZ2hNG8fqMKjVVuUpFBNR+WODQ/rRRtqa6uU2n" +
                "V8aOOZx1QJUkTdN76YOCuGET7edevjpdbRXde+HQN6mbT9OLxSZHO0aQrDyDmNhpn" +
                "aVHuQn/KtYNWCZ78XKK8wtVnflmfqE/c9xO1n/EcVvLCdg==n" +
                "-----END CERTIFICATE-----";

        PrivateKey privateKey = parsePrivateKey(privateKeyContent);
        Certificate[] certificates = parseCertificate(certificateContent).values()
                .toArray(new Certificate[]{});

        KeyStore keyStore = createEmptyKeyStore();
        keyStore.setKeyEntry("client", privateKey, null, certificates);
        System.out.println("nprivateKey:n" + privateKey);
        int certificatesLength = certificates.length;
        System.out.println("nnumber of certificates: " + certificatesLength);
        for (int i = 0; i < certificatesLength; i++) {
            System.out.println("ncertificate: " + i + " data:n" + certificates[i]);
        }
    }

    private static KeyStore createEmptyKeyStore() throws KeyStoreException, IOException, NoSuchAlgorithmException, CertificateException {
        KeyStore keyStore = KeyStore.getInstance(KEYSTORE_TYPE);
        keyStore.load(null, null);
        return keyStore;
    }

    private static PrivateKey parsePrivateKey(String identityContent) throws NoSuchAlgorithmException, InvalidKeySpecException, IOException {
        KeySpec keySpec = null;

        Matcher privateKeyMatcher = PRIVATE_KEY_PATTERN.matcher(identityContent);
        if (privateKeyMatcher.find()) {
            String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
            keySpec = new PKCS8EncodedKeySpec(decodedPrivateKeyContent);
        }

        privateKeyMatcher = RSA_PRIVATE_KEY_PATTERN.matcher(identityContent);
        if (privateKeyMatcher.find()) {
            String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
            keySpec = getKeySpecFromAsn1StructuredData(decodedPrivateKeyContent);
        }

        privateKeyMatcher = ENCRYPTED_PRIVATE_KEY_PATTERN.matcher(identityContent);
        if (privateKeyMatcher.find()) {
            String privateKeyContent = privateKeyMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedPrivateKeyContent = Base64.getDecoder().decode(privateKeyContent);
            try (ByteArrayInputStream privateKeyAsInputStream = new ByteArrayInputStream(decodedPrivateKeyContent)) {
                ASN1InputStream stream = new ASN1InputStream(new DERDecoder(), privateKeyAsInputStream);
                ASN1Sequence asn1Sequence = stream.readObject();
                ASN1OctetString privateKeyAsOctetString = (ASN1OctetString) asn1Sequence.get(1);
                ASN1OctetString saltAsOctetString = (ASN1OctetString) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(0)).get(1)).get(0);
                ASN1OctetString initializationVectorAsOctec = ((ASN1OctetString) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(1)).get(1));
                ASN1Integer iterationCount = (ASN1Integer) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) ((ASN1Sequence) asn1Sequence.get(0)).get(1)).get(0)).get(1)).get(1);
                IvParameterSpec ivParameterSpec = new IvParameterSpec(initializationVectorAsOctec.getValue());
                SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2withHmacSHA1");
                EncryptedPrivateKeyInfo encryptedPrivateKeyInfo = new EncryptedPrivateKeyInfo(secretKeyFactory.getAlgorithm(), privateKeyAsOctetString.getValue());
                int keyLength = encryptedPrivateKeyInfo.getEncoded().length;
                System.out.println("original keyLength:  " + keyLength);
                keyLength = 24 * 8; // ### fixed
                System.out.println("fixed keyLength(bit): " + keyLength);
                PBEKeySpec pbeKeySpec = new PBEKeySpec(keyPassword, saltAsOctetString.getValue(), iterationCount.getValue().intValue(), keyLength);
                Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding/");

                // SecretKey secretKey = secretKeyFactory.generateSecret(pbeKeySpec); // ### old routine
                SecretKey secretKeyPbkdf = secretKeyFactory.generateSecret(pbeKeySpec); // ### new
                SecretKey secretKey = new SecretKeySpec(secretKeyPbkdf.getEncoded(), "DESede"); // ### new

                cipher.init(Cipher.DECRYPT_MODE, secretKey, ivParameterSpec);
                keySpec = encryptedPrivateKeyInfo.getKeySpec(cipher);
                //PKCS8EncodedKeySpec keySpec = encryptedPrivateKeyInfo.getKeySpec(cipher);
            } catch (NoSuchPaddingException | InvalidKeyException | InvalidAlgorithmParameterException e) {
                e.printStackTrace();
            }
        }

        Objects.requireNonNull(keySpec);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_FACTORY_ALGORITHM);
        return keyFactory.generatePrivate(keySpec);
    }

    private static KeySpec getKeySpecFromAsn1StructuredData(byte[] decodedPrivateKeyContent) throws IOException {
        try(ByteArrayInputStream privateKeyAsInputStream = new ByteArrayInputStream(decodedPrivateKeyContent)) {
            ASN1InputStream stream = new ASN1InputStream(new DERDecoder(), privateKeyAsInputStream);
            ASN1Sequence asn1Sequence = stream.readObject();

            if (asn1Sequence.getValue().size() < 9) {
                throw new RuntimeException("Parsed key content doesn't have the minimum required sequence size of 9");
            }

            BigInteger modulus = extractIntValueFrom(asn1Sequence.get(1));
            BigInteger publicExponent = extractIntValueFrom(asn1Sequence.get(2));
            BigInteger privateExponent = extractIntValueFrom(asn1Sequence.get(3));
            BigInteger primeP = extractIntValueFrom(asn1Sequence.get(4));
            BigInteger primeQ = extractIntValueFrom(asn1Sequence.get(5));
            BigInteger primeExponentP = extractIntValueFrom(asn1Sequence.get(6));
            BigInteger primeExponentQ = extractIntValueFrom(asn1Sequence.get(7));
            BigInteger crtCoefficient = extractIntValueFrom(asn1Sequence.get(8));

            return new RSAPrivateCrtKeySpec(
                    modulus, publicExponent, privateExponent,
                    primeP, primeQ, primeExponentP, primeExponentQ, crtCoefficient
            );
        }
    }

    private static BigInteger extractIntValueFrom(ASN1Object<?> asn1Object) {
        if (asn1Object instanceof ASN1Integer) {
            return ((ASN1Integer) asn1Object).getValue();
        } else {
            throw new RuntimeException(String.format(
                    "Unable to parse the provided value of the object type [%s]. The type should be an instance of [%s]",
                    asn1Object.getClass().getName(), ASN1Integer.class.getName())
            );
        }
    }

    private static Map<String, Certificate> parseCertificate(String certificateContent) throws IOException, CertificateException {
        Map<String, Certificate> certificates = new HashMap<>();
        Matcher certificateMatcher = CERTIFICATE_PATTERN.matcher(certificateContent);

        while (certificateMatcher.find()) {
            String sanitizedCertificate = certificateMatcher.group(1).replace(NEW_LINE, EMPTY).trim();
            byte[] decodedCertificate = Base64.getDecoder().decode(sanitizedCertificate);
            try(ByteArrayInputStream certificateAsInputStream = new ByteArrayInputStream(decodedCertificate)) {
                CertificateFactory certificateFactory = CertificateFactory.getInstance(CERTIFICATE_TYPE);
                Certificate certificate = certificateFactory.generateCertificate(certificateAsInputStream);
                certificates.put(UUID.randomUUID().toString(), certificate);
            }
        }
        return certificates;
    }
}