* https://www.openssl.org/docs/man1.1.0/crypto/PEM_write_bio_PrivateKey_traditional.html
*/
private static byte[] generateOpenSslKey(char[] password, byte[] salt, int keyLength) {
byte[] passwordBytes = CharArrays.toUtf8Bytes(password);
MessageDigest md5 = SslUtil.messageDigest("md5");
byte[] key = new byte[keyLength];
int copied = 0;
int remaining;
while (copied < keyLength) {
remaining = keyLength - copied;
md5.update(passwordBytes, 0, passwordBytes.length);
md5.update(salt, 0, 8);// AES IV (salt) is longer but we only need 8 bytes
byte[] tempDigest = md5.digest();
int bytesToCopy = (remaining > 16) ? 16 : remaining; // MD5 digests are 16 bytes
System.arraycopy(tempDigest, 0, key, copied, bytesToCopy);
copied += bytesToCopy;
if (remaining == 0) {
break;
}
md5.update(tempDigest, 0, 16); // use previous round digest as IV
}
Arrays.fill(passwordBytes, (byte) 0);
return key;
}
/**
* Converts a hexadecimal string to a byte array
*/
private static byte[] hexStringToByteArray(String hexString) {
int len = hexString.length();
if (len % 2 == 0) {
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
final int k = Character.digit(hexString.charAt(i), 16);
final int l = Character.digit(hexString.charAt(i + 1), 16);
if (k == -1 || l == -1) {
throw new IllegalStateException("String [" + hexString + "] is not hexadecimal");
}
data[i / 2] = (byte) ((k << 4) + l);
}
return data;
} else {
throw new IllegalStateException(
"Hexadecimal string [" + hexString + "] has odd length and cannot be converted to a byte array"
);
}
}
/**
* Parses a DER encoded EC key to an {@link ECPrivateKeySpec} using a minimal {@link DerParser}
*
* @param keyBytes the private key raw bytes
* @return {@link ECPrivateKeySpec}
* @throws IOException if the DER encoded key can't be parsed
*/
private static ECPrivateKeySpec parseEcDer(byte[] keyBytes) throws IOException, GeneralSecurityException {
DerParser parser = new DerParser(keyBytes);
DerParser.Asn1Object sequence = parser.readAsn1Object();
parser = sequence.getParser();
parser.readAsn1Object().getInteger(); // version
String keyHex = parser.readAsn1Object().getString();
BigInteger privateKeyInt = new BigInteger(keyHex, 16);
DerParser.Asn1Object choice = parser.readAsn1Object();
parser = choice.getParser();
String namedCurve = getEcCurveNameFromOid(parser.readAsn1Object().getOid());
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC");
AlgorithmParameterSpec algorithmParameterSpec = new ECGenParameterSpec(namedCurve);
keyPairGenerator.initialize(algorithmParameterSpec);
ECParameterSpec parameterSpec = ((ECKey) keyPairGenerator.generateKeyPair().getPrivate()).getParams();
return new ECPrivateKeySpec(privateKeyInt, parameterSpec);
}
/**
* Parses a DER encoded RSA key to a {@link RSAPrivateCrtKeySpec} using a minimal {@link DerParser}
*
* @param keyBytes the private key raw bytes
* @return {@link RSAPrivateCrtKeySpec}
* @throws IOException if the DER encoded key can't be parsed
*/
private static RSAPrivateCrtKeySpec parseRsaDer(byte[] keyBytes) throws IOException {
DerParser parser = new DerParser(keyBytes);
DerParser.Asn1Object sequence = parser.readAsn1Object();
parser = sequence.getParser();
parser.readAsn1Object().getInteger(); // (version) We don't need it but must read to get to modulus
BigInteger modulus = parser.readAsn1Object().getInteger();
BigInteger publicExponent = parser.readAsn1Object().getInteger();
BigInteger privateExponent = parser.readAsn1Object().getInteger();
BigInteger prime1 = parser.readAsn1Object().getInteger();
BigInteger prime2 = parser.readAsn1Object().getInteger();
BigInteger exponent1 = parser.readAsn1Object().getInteger();
BigInteger exponent2 = parser.readAsn1Object().getInteger();
BigInteger coefficient = parser.readAsn1Object().getInteger();
return new RSAPrivateCrtKeySpec(modulus, publicExponent, privateExponent, prime1, prime2, exponent1, exponent2, coefficient);
}
/**
* Parses a DER encoded DSA key to a {@link DSAPrivateKeySpec} using a minimal {@link DerParser}
*
* @param keyBytes the private key raw bytes
* @return {@link DSAPrivateKeySpec}
* @throws IOException if the DER encoded key can't be parsed
*/
private static DSAPrivateKeySpec parseDsaDer(byte[] keyBytes) throws IOException {
DerParser parser = new DerParser(keyBytes);
DerParser.Asn1Object sequence = parser.readAsn1Object();
parser = sequence.getParser();
parser.readAsn1Object().getInteger(); // (version) We don't need it but must read to get to p
BigInteger p = parser.readAsn1Object().getInteger();
BigInteger q = parser.readAsn1Object().getInteger();
BigInteger g = parser.readAsn1Object().getInteger();
parser.readAsn1Object().getInteger(); // we don't need x
BigInteger x = parser.readAsn1Object().getInteger();
return new DSAPrivateKeySpec(x, p, q, g);
}
/**
* Parses a DER encoded private key and reads its algorithm identifier Object OID.
*
* @param keyBytes the private key raw bytes
* @return A string identifier for the key algorithm (RSA, DSA, or EC)
* @throws GeneralSecurityException if the algorithm oid that is parsed from ASN.1 is unknown
* @throws IOException if the DER encoded key can't be parsed
*/
private static String getKeyAlgorithmIdentifier(byte[] keyBytes) throws IOException, GeneralSecurityException {
DerParser parser = new DerParser(keyBytes);
DerParser.Asn1Object sequence = parser.readAsn1Object();
parser = sequence.getParser();
parser.readAsn1Object().getInteger(); // version
DerParser.Asn1Object algSequence = parser.readAsn1Object();
parser = algSequence.getParser();
String oidString = parser.readAsn1Object().getOid();
return switch (oidString) {
case "1.2.840.10040.4.1" -> "DSA";
case "1.2.840.113549.1.1.1" -> "RSA";
case "1.2.840.10045.2.1" -> "EC";
default -> throw new GeneralSecurityException(
"Error parsing key algorithm identifier. Algorithm with OID [" + oidString + "] is not supported"
);
};
}
public static List