I am writing a small piece of code which reads public and private key stored in .pem file. I am using the following commands to generate the keys.
Below command to generate pair of key.
$openssl genrsa -out mykey.pem 2048
This command to generate the private key
$openssl pkcs8 -topk8 -inform PEM -outform PEM -in mykey.pem \
-out private_key.pem -nocrypt
and this command to get the public key.
$ openssl rsa -in mykey.pem -pubout -outform DER -out public_key.der
I have written two methods which reads the private key and public key respectively.
public PrivateKey getPemPrivateKey(String filename, String algorithm) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
String temp = new String(keyBytes);
String privKeyPEM = temp.replace("-----BEGIN PRIVATE KEY-----\n", "");
privKeyPEM = privKeyPEM.replace("-----END PRIVATE KEY-----", "");
//System.out.println("Private key\n"+privKeyPEM);
Base64 b64 = new Base64();
byte [] decoded = b64.decode(privKeyPEM);
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance(algorithm);
return kf.generatePrivate(spec);
}
public PublicKey getPemPublicKey(String filename, String algorithm) throws Exception {
File f = new File(filename);
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
String temp = new String(keyBytes);
String publicKeyPEM = temp.replace("-----BEGIN PUBLIC KEY-----\n", "");
publicKeyPEM = publicKeyPEM.replace("-----END PUBLIC KEY-----", "");
Base64 b64 = new Base64();
byte [] decoded = b64.decode(publicKeyPEM);
X509EncodedKeySpec spec =
new X509EncodedKeySpec(decoded);
KeyFactory kf = KeyFactory.getInstance(algorithm);
return kf.generatePublic(spec);
}
I feel like this is a naive way of doing it. I couldn't get any better way of doing it over internet. Can anyone suggest me what is the best way of writing the same code to handle the generic cases. I don' want to use any kind of third party library.
I have very basic knowledge of singing/encrypting and hardly use any java security APIs. So if I am not making sense somewhere then please point out.
Try this class.
package groovy;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import org.apache.commons.codec.binary.Base64;
public class RSA {
private static String getKey(String filename) throws IOException {
// Read key from file
String strKeyPEM = "";
BufferedReader br = new BufferedReader(new FileReader(filename));
String line;
while ((line = br.readLine()) != null) {
strKeyPEM += line + "\n";
}
br.close();
return strKeyPEM;
}
public static RSAPrivateKey getPrivateKey(String filename) throws IOException, GeneralSecurityException {
String privateKeyPEM = getKey(filename);
return getPrivateKeyFromString(privateKeyPEM);
}
public static RSAPrivateKey getPrivateKeyFromString(String key) throws IOException, GeneralSecurityException {
String privateKeyPEM = key;
privateKeyPEM = privateKeyPEM.replace("-----BEGIN PRIVATE KEY-----\n", "");
privateKeyPEM = privateKeyPEM.replace("-----END PRIVATE KEY-----", "");
byte[] encoded = Base64.decodeBase64(privateKeyPEM);
KeyFactory kf = KeyFactory.getInstance("RSA");
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
RSAPrivateKey privKey = (RSAPrivateKey) kf.generatePrivate(keySpec);
return privKey;
}
public static RSAPublicKey getPublicKey(String filename) throws IOException, GeneralSecurityException {
String publicKeyPEM = getKey(filename);
return getPublicKeyFromString(publicKeyPEM);
}
public static RSAPublicKey getPublicKeyFromString(String key) throws IOException, GeneralSecurityException {
String publicKeyPEM = key;
publicKeyPEM = publicKeyPEM.replace("-----BEGIN PUBLIC KEY-----\n", "");
publicKeyPEM = publicKeyPEM.replace("-----END PUBLIC KEY-----", "");
byte[] encoded = Base64.decodeBase64(publicKeyPEM);
KeyFactory kf = KeyFactory.getInstance("RSA");
RSAPublicKey pubKey = (RSAPublicKey) kf.generatePublic(new X509EncodedKeySpec(encoded));
return pubKey;
}
public static String sign(PrivateKey privateKey, String message) throws NoSuchAlgorithmException, InvalidKeyException, SignatureException, UnsupportedEncodingException {
Signature sign = Signature.getInstance("SHA1withRSA");
sign.initSign(privateKey);
sign.update(message.getBytes("UTF-8"));
return new String(Base64.encodeBase64(sign.sign()), "UTF-8");
}
public static boolean verify(PublicKey publicKey, String message, String signature) throws SignatureException, NoSuchAlgorithmException, UnsupportedEncodingException, InvalidKeyException {
Signature sign = Signature.getInstance("SHA1withRSA");
sign.initVerify(publicKey);
sign.update(message.getBytes("UTF-8"));
return sign.verify(Base64.decodeBase64(signature.getBytes("UTF-8")));
}
public static String encrypt(String rawText, PublicKey publicKey) throws IOException, GeneralSecurityException {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return Base64.encodeBase64String(cipher.doFinal(rawText.getBytes("UTF-8")));
}
public static String decrypt(String cipherText, PrivateKey privateKey) throws IOException, GeneralSecurityException {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return new String(cipher.doFinal(Base64.decodeBase64(cipherText)), "UTF-8");
}
}
Required jar library "common-codec-1.6"
Java 9+:
private byte[] loadPEM(String resource) throws IOException {
URL url = getClass().getResource(resource);
InputStream in = url.openStream();
String pem = new String(in.readAllBytes(), StandardCharsets.ISO_8859_1);
Pattern parse = Pattern.compile("(?m)(?s)^---*BEGIN.*---*$(.*)^---*END.*---*$.*");
String encoded = parse.matcher(pem).replaceFirst("$1");
return Base64.getMimeDecoder().decode(encoded);
}
#Test
public void test() throws Exception {
KeyFactory kf = KeyFactory.getInstance("RSA");
CertificateFactory cf = CertificateFactory.getInstance("X.509");
PrivateKey key = kf.generatePrivate(new PKCS8EncodedKeySpec(loadPEM("test.key")));
PublicKey pub = kf.generatePublic(new X509EncodedKeySpec(loadPEM("test.pub")));
Certificate crt = cf.generateCertificate(getClass().getResourceAsStream("test.crt"));
}
Java 8:
replace the in.readAllBytes() call with a call to this:
byte[] readAllBytes(InputStream in) throws IOException {
ByteArrayOutputStream baos= new ByteArrayOutputStream();
byte[] buf = new byte[1024];
for (int read=0; read != -1; read = in.read(buf)) { baos.write(buf, 0, read); }
return baos.toByteArray();
}
thanks to Daniel for noticing API compatibility issues
One option is to use bouncycastle's PEMParser:
Class for parsing OpenSSL PEM encoded streams containing X509
certificates, PKCS8 encoded keys and PKCS7 objects.
In the case of PKCS7 objects the reader will return a CMS ContentInfo
object. Public keys will be returned as well formed
SubjectPublicKeyInfo objects, private keys will be returned as well
formed PrivateKeyInfo objects. In the case of a private key a
PEMKeyPair will normally be returned if the encoding contains both the
private and public key definition. CRLs, Certificates, PKCS#10
requests, and Attribute Certificates will generate the appropriate BC
holder class.
Here is an example of using the Parser test code:
package org.bouncycastle.openssl.test;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
import java.security.Signature;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAPrivateKey;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.cms.CMSObjectIdentifiers;
import org.bouncycastle.asn1.cms.ContentInfo;
import org.bouncycastle.asn1.pkcs.PrivateKeyInfo;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.asn1.x9.ECNamedCurveTable;
import org.bouncycastle.asn1.x9.X9ECParameters;
import org.bouncycastle.cert.X509CertificateHolder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openssl.PEMDecryptorProvider;
import org.bouncycastle.openssl.PEMEncryptedKeyPair;
import org.bouncycastle.openssl.PEMKeyPair;
import org.bouncycastle.openssl.PEMParser;
import org.bouncycastle.openssl.PEMWriter;
import org.bouncycastle.openssl.PasswordFinder;
import org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter;
import org.bouncycastle.openssl.jcajce.JceOpenSSLPKCS8DecryptorProviderBuilder;
import org.bouncycastle.openssl.jcajce.JcePEMDecryptorProviderBuilder;
import org.bouncycastle.operator.InputDecryptorProvider;
import org.bouncycastle.pkcs.PKCS8EncryptedPrivateKeyInfo;
import org.bouncycastle.util.test.SimpleTest;
/**
* basic class for reading test.pem - the password is "secret"
*/
public class ParserTest
extends SimpleTest
{
private static class Password
implements PasswordFinder
{
char[] password;
Password(
char[] word)
{
this.password = word;
}
public char[] getPassword()
{
return password;
}
}
public String getName()
{
return "PEMParserTest";
}
private PEMParser openPEMResource(
String fileName)
{
InputStream res = this.getClass().getResourceAsStream(fileName);
Reader fRd = new BufferedReader(new InputStreamReader(res));
return new PEMParser(fRd);
}
public void performTest()
throws Exception
{
PEMParser pemRd = openPEMResource("test.pem");
Object o;
PEMKeyPair pemPair;
KeyPair pair;
while ((o = pemRd.readObject()) != null)
{
if (o instanceof KeyPair)
{
//pair = (KeyPair)o;
//System.out.println(pair.getPublic());
//System.out.println(pair.getPrivate());
}
else
{
//System.out.println(o.toString());
}
}
// test bogus lines before begin are ignored.
pemRd = openPEMResource("extratest.pem");
while ((o = pemRd.readObject()) != null)
{
if (!(o instanceof X509CertificateHolder))
{
fail("wrong object found");
}
}
//
// pkcs 7 data
//
pemRd = openPEMResource("pkcs7.pem");
ContentInfo d = (ContentInfo)pemRd.readObject();
if (!d.getContentType().equals(CMSObjectIdentifiers.envelopedData))
{
fail("failed envelopedData check");
}
//
// ECKey
//
pemRd = openPEMResource("eckey.pem");
ASN1ObjectIdentifier ecOID = (ASN1ObjectIdentifier)pemRd.readObject();
X9ECParameters ecSpec = ECNamedCurveTable.getByOID(ecOID);
if (ecSpec == null)
{
fail("ecSpec not found for named curve");
}
pemPair = (PEMKeyPair)pemRd.readObject();
pair = new JcaPEMKeyConverter().setProvider("BC").getKeyPair(pemPair);
Signature sgr = Signature.getInstance("ECDSA", "BC");
sgr.initSign(pair.getPrivate());
byte[] message = new byte[] { (byte)'a', (byte)'b', (byte)'c' };
sgr.update(message);
byte[] sigBytes = sgr.sign();
sgr.initVerify(pair.getPublic());
sgr.update(message);
if (!sgr.verify(sigBytes))
{
fail("EC verification failed");
}
if (!pair.getPublic().getAlgorithm().equals("ECDSA"))
{
fail("wrong algorithm name on public got: " + pair.getPublic().getAlgorithm());
}
if (!pair.getPrivate().getAlgorithm().equals("ECDSA"))
{
fail("wrong algorithm name on private");
}
//
// ECKey -- explicit parameters
//
pemRd = openPEMResource("ecexpparam.pem");
ecSpec = (X9ECParameters)pemRd.readObject();
pemPair = (PEMKeyPair)pemRd.readObject();
pair = new JcaPEMKeyConverter().setProvider("BC").getKeyPair(pemPair);
sgr = Signature.getInstance("ECDSA", "BC");
sgr.initSign(pair.getPrivate());
message = new byte[] { (byte)'a', (byte)'b', (byte)'c' };
sgr.update(message);
sigBytes = sgr.sign();
sgr.initVerify(pair.getPublic());
sgr.update(message);
if (!sgr.verify(sigBytes))
{
fail("EC verification failed");
}
if (!pair.getPublic().getAlgorithm().equals("ECDSA"))
{
fail("wrong algorithm name on public got: " + pair.getPublic().getAlgorithm());
}
if (!pair.getPrivate().getAlgorithm().equals("ECDSA"))
{
fail("wrong algorithm name on private");
}
//
// writer/parser test
//
KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA", "BC");
pair = kpGen.generateKeyPair();
keyPairTest("RSA", pair);
kpGen = KeyPairGenerator.getInstance("DSA", "BC");
kpGen.initialize(512, new SecureRandom());
pair = kpGen.generateKeyPair();
keyPairTest("DSA", pair);
//
// PKCS7
//
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
PEMWriter pWrt = new PEMWriter(new OutputStreamWriter(bOut));
pWrt.writeObject(d);
pWrt.close();
pemRd = new PEMParser(new InputStreamReader(new ByteArrayInputStream(bOut.toByteArray())));
d = (ContentInfo)pemRd.readObject();
if (!d.getContentType().equals(CMSObjectIdentifiers.envelopedData))
{
fail("failed envelopedData recode check");
}
// OpenSSL test cases (as embedded resources)
doOpenSslDsaTest("unencrypted");
doOpenSslRsaTest("unencrypted");
doOpenSslTests("aes128");
doOpenSslTests("aes192");
doOpenSslTests("aes256");
doOpenSslTests("blowfish");
doOpenSslTests("des1");
doOpenSslTests("des2");
doOpenSslTests("des3");
doOpenSslTests("rc2_128");
doOpenSslDsaTest("rc2_40_cbc");
doOpenSslRsaTest("rc2_40_cbc");
doOpenSslDsaTest("rc2_64_cbc");
doOpenSslRsaTest("rc2_64_cbc");
doDudPasswordTest("7fd98", 0, "corrupted stream - out of bounds length found");
doDudPasswordTest("ef677", 1, "corrupted stream - out of bounds length found");
doDudPasswordTest("800ce", 2, "unknown tag 26 encountered");
doDudPasswordTest("b6cd8", 3, "DEF length 81 object truncated by 56");
doDudPasswordTest("28ce09", 4, "DEF length 110 object truncated by 28");
doDudPasswordTest("2ac3b9", 5, "DER length more than 4 bytes: 11");
doDudPasswordTest("2cba96", 6, "DEF length 100 object truncated by 35");
doDudPasswordTest("2e3354", 7, "DEF length 42 object truncated by 9");
doDudPasswordTest("2f4142", 8, "DER length more than 4 bytes: 14");
doDudPasswordTest("2fe9bb", 9, "DER length more than 4 bytes: 65");
doDudPasswordTest("3ee7a8", 10, "DER length more than 4 bytes: 57");
doDudPasswordTest("41af75", 11, "unknown tag 16 encountered");
doDudPasswordTest("1704a5", 12, "corrupted stream detected");
doDudPasswordTest("1c5822", 13, "unknown object in getInstance: org.bouncycastle.asn1.DERUTF8String");
doDudPasswordTest("5a3d16", 14, "corrupted stream detected");
doDudPasswordTest("8d0c97", 15, "corrupted stream detected");
doDudPasswordTest("bc0daf", 16, "corrupted stream detected");
doDudPasswordTest("aaf9c4d",17, "corrupted stream - out of bounds length found");
doNoPasswordTest();
// encrypted private key test
InputDecryptorProvider pkcs8Prov = new JceOpenSSLPKCS8DecryptorProviderBuilder().build("password".toCharArray());
pemRd = openPEMResource("enckey.pem");
PKCS8EncryptedPrivateKeyInfo encPrivKeyInfo = (PKCS8EncryptedPrivateKeyInfo)pemRd.readObject();
JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider("BC");
RSAPrivateCrtKey privKey = (RSAPrivateCrtKey)converter.getPrivateKey(encPrivKeyInfo.decryptPrivateKeyInfo(pkcs8Prov));
if (!privKey.getPublicExponent().equals(new BigInteger("10001", 16)))
{
fail("decryption of private key data check failed");
}
// general PKCS8 test
pemRd = openPEMResource("pkcs8test.pem");
Object privInfo;
while ((privInfo = pemRd.readObject()) != null)
{
if (privInfo instanceof PrivateKeyInfo)
{
privKey = (RSAPrivateCrtKey)converter.getPrivateKey(PrivateKeyInfo.getInstance(privInfo));
}
else
{
privKey = (RSAPrivateCrtKey)converter.getPrivateKey(((PKCS8EncryptedPrivateKeyInfo)privInfo).decryptPrivateKeyInfo(pkcs8Prov));
}
if (!privKey.getPublicExponent().equals(new BigInteger("10001", 16)))
{
fail("decryption of private key data check failed");
}
}
}
private void keyPairTest(
String name,
KeyPair pair)
throws IOException
{
PEMParser pemRd;
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
PEMWriter pWrt = new PEMWriter(new OutputStreamWriter(bOut));
pWrt.writeObject(pair.getPublic());
pWrt.close();
pemRd = new PEMParser(new InputStreamReader(new ByteArrayInputStream(bOut.toByteArray())));
SubjectPublicKeyInfo pub = SubjectPublicKeyInfo.getInstance(pemRd.readObject());
JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider("BC");
PublicKey k = converter.getPublicKey(pub);
if (!k.equals(pair.getPublic()))
{
fail("Failed public key read: " + name);
}
bOut = new ByteArrayOutputStream();
pWrt = new PEMWriter(new OutputStreamWriter(bOut));
pWrt.writeObject(pair.getPrivate());
pWrt.close();
pemRd = new PEMParser(new InputStreamReader(new ByteArrayInputStream(bOut.toByteArray())));
KeyPair kPair = converter.getKeyPair((PEMKeyPair)pemRd.readObject());
if (!kPair.getPrivate().equals(pair.getPrivate()))
{
fail("Failed private key read: " + name);
}
if (!kPair.getPublic().equals(pair.getPublic()))
{
fail("Failed private key public read: " + name);
}
}
private void doOpenSslTests(
String baseName)
throws IOException
{
doOpenSslDsaModesTest(baseName);
doOpenSslRsaModesTest(baseName);
}
private void doOpenSslDsaModesTest(
String baseName)
throws IOException
{
doOpenSslDsaTest(baseName + "_cbc");
doOpenSslDsaTest(baseName + "_cfb");
doOpenSslDsaTest(baseName + "_ecb");
doOpenSslDsaTest(baseName + "_ofb");
}
private void doOpenSslRsaModesTest(
String baseName)
throws IOException
{
doOpenSslRsaTest(baseName + "_cbc");
doOpenSslRsaTest(baseName + "_cfb");
doOpenSslRsaTest(baseName + "_ecb");
doOpenSslRsaTest(baseName + "_ofb");
}
private void doOpenSslDsaTest(
String name)
throws IOException
{
String fileName = "dsa/openssl_dsa_" + name + ".pem";
doOpenSslTestFile(fileName, DSAPrivateKey.class);
}
private void doOpenSslRsaTest(
String name)
throws IOException
{
String fileName = "rsa/openssl_rsa_" + name + ".pem";
doOpenSslTestFile(fileName, RSAPrivateKey.class);
}
private void doOpenSslTestFile(
String fileName,
Class expectedPrivKeyClass)
throws IOException
{
JcaPEMKeyConverter converter = new JcaPEMKeyConverter().setProvider("BC");
PEMDecryptorProvider decProv = new JcePEMDecryptorProviderBuilder().setProvider("BC").build("changeit".toCharArray());
PEMParser pr = openPEMResource("data/" + fileName);
Object o = pr.readObject();
if (o == null || !((o instanceof PEMKeyPair) || (o instanceof PEMEncryptedKeyPair)))
{
fail("Didn't find OpenSSL key");
}
KeyPair kp = (o instanceof PEMEncryptedKeyPair) ?
converter.getKeyPair(((PEMEncryptedKeyPair)o).decryptKeyPair(decProv)) : converter.getKeyPair((PEMKeyPair)o);
PrivateKey privKey = kp.getPrivate();
if (!expectedPrivKeyClass.isInstance(privKey))
{
fail("Returned key not of correct type");
}
}
private void doDudPasswordTest(String password, int index, String message)
{
// illegal state exception check - in this case the wrong password will
// cause an underlying class cast exception.
try
{
PEMDecryptorProvider decProv = new JcePEMDecryptorProviderBuilder().setProvider("BC").build(password.toCharArray());
PEMParser pemRd = openPEMResource("test.pem");
Object o;
while ((o = pemRd.readObject()) != null)
{
if (o instanceof PEMEncryptedKeyPair)
{
((PEMEncryptedKeyPair)o).decryptKeyPair(decProv);
}
}
fail("issue not detected: " + index);
}
catch (IOException e)
{
if (e.getCause() != null && !e.getCause().getMessage().endsWith(message))
{
fail("issue " + index + " exception thrown, but wrong message");
}
else if (e.getCause() == null && !e.getMessage().equals(message))
{
e.printStackTrace();
fail("issue " + index + " exception thrown, but wrong message");
}
}
}
private void doNoPasswordTest()
throws IOException
{
PEMDecryptorProvider decProv = new JcePEMDecryptorProviderBuilder().setProvider("BC").build("".toCharArray());
PEMParser pemRd = openPEMResource("smimenopw.pem");
Object o;
PrivateKeyInfo key = null;
while ((o = pemRd.readObject()) != null)
{
key = (PrivateKeyInfo)o;
}
if (key == null)
{
fail("private key not detected");
}
}
public static void main(
String[] args)
{
Security.addProvider(new BouncyCastleProvider());
runTest(new ParserTest());
}
}
Well, my code is like yours, with little diferences...
public static X509Certificate loadPublicX509(String fileName)
throws GeneralSecurityException {
InputStream is = null;
X509Certificate crt = null;
try {
is = fileName.getClass().getResourceAsStream("/" + fileName);
CertificateFactory cf = CertificateFactory.getInstance("X.509");
crt = (X509Certificate)cf.generateCertificate(is);
} finally {
closeSilent(is);
}
return crt;
}
public static PrivateKey loadPrivateKey(String fileName)
throws IOException, GeneralSecurityException {
PrivateKey key = null;
InputStream is = null;
try {
is = fileName.getClass().getResourceAsStream("/" + fileName);
BufferedReader br = new BufferedReader(new InputStreamReader(is));
StringBuilder builder = new StringBuilder();
boolean inKey = false;
for (String line = br.readLine(); line != null; line = br.readLine()) {
if (!inKey) {
if (line.startsWith("-----BEGIN ") &&
line.endsWith(" PRIVATE KEY-----")) {
inKey = true;
}
continue;
}
else {
if (line.startsWith("-----END ") &&
line.endsWith(" PRIVATE KEY-----")) {
inKey = false;
break;
}
builder.append(line);
}
}
//
byte[] encoded = DatatypeConverter.parseBase64Binary(builder.toString());
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
KeyFactory kf = KeyFactory.getInstance("RSA");
key = kf.generatePrivate(keySpec);
} finally {
closeSilent(is);
}
return key;
}
public static void closeSilent(final InputStream is) {
if (is == null) return;
try { is.close(); } catch (Exception ign) {}
}
Java supports using DER for public and private keys out of the box (which is basically the same as PEM, as the OP asks, except PEM files contain base 64 data plus header and footer lines).
You can rely on this code (modulo exception handling) without any external library if you are on Java 8+ (this assumes your key files are available in the classpath):
class Signer {
private KeyFactory keyFactory;
public Signer() {
this.keyFactory = KeyFactory.getInstance("RSA");
}
public PublicKey getPublicKey() {
byte[] publicKey = readFileAsBytes("public-key.der");
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);
return keyFactory.generatePublic(keySpec);
}
public PrivateKey getPrivateKey() {
byte[] privateKey = readFileAsBytes("private-key.der");
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKey);
return keyFactory.generatePrivate(keySpec);
}
private URI readFileAsBytes(String name) {
URI fileUri = getClass().getClassLoader().getResource(name).toURI();
return Files.readAllBytes(Paths.get(fileUri));
}
}
For the record, you can convert a PEM key to a DER key with the following command:
$ openssl pkcs8 -topk8 -inform PEM -outform DER -in private-key.pem -out private-key.der -nocrypt
And get the public key in DER with:
$ openssl rsa -in private-key.pem -pubout -outform DER -out public-key.der
I think in your private key definition, You should replace:
X509EncodedKeySpec spec = new X509EncodedKeySpec(decoded);
with:
PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(decoded);
Look your openssl command:
$openssl **pkcs8** -topk8 -inform PEM -outform PEM -in mykey.pem \ -out private_key.pem -nocrypt
And the java Exception:
Only PCKS8 codification
Java libs makes it almost a one liner to read the public cert, as generated by openssl:
val certificate: X509Certificate = ByteArrayInputStream(
publicKeyCert.toByteArray(Charsets.US_ASCII))
.use {
CertificateFactory.getInstance("X.509")
.generateCertificate(it) as X509Certificate
}
But, o hell, reading the private key was problematic:
First had to remove the begin and end tags, which is not nessarry when reading the public key.
Then I had to remove all the new lines, otherwise it croaks!
Then I had to decode back to bytes using byte 64
Then I was able to produce an RSAPrivateKey.
see this: Final solution in kotlin
Read public key from pem (PK or Cert). Depends on Bouncycastle.
private static PublicKey getPublicKeyFromPEM(Reader reader) throws IOException {
PublicKey key;
try (PEMParser pem = new PEMParser(reader)) {
JcaPEMKeyConverter jcaPEMKeyConverter = new JcaPEMKeyConverter();
Object pemContent = pem.readObject();
if (pemContent instanceof PEMKeyPair) {
PEMKeyPair pemKeyPair = (PEMKeyPair) pemContent;
KeyPair keyPair = jcaPEMKeyConverter.getKeyPair(pemKeyPair);
key = keyPair.getPublic();
} else if (pemContent instanceof SubjectPublicKeyInfo) {
SubjectPublicKeyInfo keyInfo = (SubjectPublicKeyInfo) pemContent;
key = jcaPEMKeyConverter.getPublicKey(keyInfo);
} else if (pemContent instanceof X509CertificateHolder) {
X509CertificateHolder cert = (X509CertificateHolder) pemContent;
key = jcaPEMKeyConverter.getPublicKey(cert.getSubjectPublicKeyInfo());
} else {
throw new IllegalArgumentException("Unsupported public key format '" +
pemContent.getClass().getSimpleName() + '"');
}
}
return key;
}
Read private key from PEM:
private static PrivateKey getPrivateKeyFromPEM(Reader reader) throws IOException {
PrivateKey key;
try (PEMParser pem = new PEMParser(reader)) {
JcaPEMKeyConverter jcaPEMKeyConverter = new JcaPEMKeyConverter();
Object pemContent = pem.readObject();
if (pemContent instanceof PEMKeyPair) {
PEMKeyPair pemKeyPair = (PEMKeyPair) pemContent;
KeyPair keyPair = jcaPEMKeyConverter.getKeyPair(pemKeyPair);
key = keyPair.getPrivate();
} else if (pemContent instanceof PrivateKeyInfo) {
PrivateKeyInfo privateKeyInfo = (PrivateKeyInfo) pemContent;
key = jcaPEMKeyConverter.getPrivateKey(privateKeyInfo);
} else {
throw new IllegalArgumentException("Unsupported private key format '" +
pemContent.getClass().getSimpleName() + '"');
}
}
return key;
}
If a PEM contains only one RSA private key without encryption, it must be an ASN.1 sequence structure including 9 numbers to present a Chinese Remainder Theorem (CRT) key:
version (always 0)
modulus (n)
public exponent (e, always 65537)
private exponent (d)
prime p
prime q
d mod (p - 1) (dp)
d mod (q - 1) (dq)
q^-1 mod p (qinv)
We can implement an RSAPrivateCrtKey:
class RSAPrivateCrtKeyImpl implements RSAPrivateCrtKey {
private static final long serialVersionUID = 1L;
BigInteger n, e, d, p, q, dp, dq, qinv;
#Override
public BigInteger getModulus() {
return n;
}
#Override
public BigInteger getPublicExponent() {
return e;
}
#Override
public BigInteger getPrivateExponent() {
return d;
}
#Override
public BigInteger getPrimeP() {
return p;
}
#Override
public BigInteger getPrimeQ() {
return q;
}
#Override
public BigInteger getPrimeExponentP() {
return dp;
}
#Override
public BigInteger getPrimeExponentQ() {
return dq;
}
#Override
public BigInteger getCrtCoefficient() {
return qinv;
}
#Override
public String getAlgorithm() {
return "RSA";
}
#Override
public String getFormat() {
throw new UnsupportedOperationException();
}
#Override
public byte[] getEncoded() {
throw new UnsupportedOperationException();
}
}
Then read the private key from a PEM file:
import sun.security.util.DerInputStream;
import sun.security.util.DerValue;
static RSAPrivateCrtKey getRSAPrivateKey(String keyFile) {
RSAPrivateCrtKeyImpl prvKey = new RSAPrivateCrtKeyImpl();
try (BufferedReader in = new BufferedReader(new FileReader(keyFile))) {
StringBuilder sb = new StringBuilder();
String line;
while ((line = in.readLine()) != null) {
// skip "-----BEGIN/END RSA PRIVATE KEY-----"
if (!line.startsWith("--") || !line.endsWith("--")) {
sb.append(line);
}
}
DerInputStream der = new DerValue(Base64.
getDecoder().decode(sb.toString())).getData();
der.getBigInteger(); // 0
prvKey.n = der.getBigInteger();
prvKey.e = der.getBigInteger(); // 65537
prvKey.d = der.getBigInteger();
prvKey.p = der.getBigInteger();
prvKey.q = der.getBigInteger();
prvKey.dp = der.getBigInteger();
prvKey.dq = der.getBigInteger();
prvKey.qinv = der.getBigInteger();
} catch (IllegalArgumentException | IOException e) {
logger.warn(keyFile + ": " + e.getMessage());
return null;
}
}
To get the public key you can simply do:
public static PublicKey getPublicKeyFromCertFile(final String certfile){
return new X509CertImpl(new FileInputStream(new File(certfile))).getPublicKey();
To get the private key is trickier, you can:
public static PrivateKey getPrivateKeyFromKeyFile(final String keyfile){
try {
Process p;
p = Runtime.getRuntime().exec("openssl pkcs8 -nocrypt -topk8 -inform PEM " +
"-in " + keyfile + " -outform DER -out " + keyfile + ".der");
p.waitFor();
System.out.println("Command executed" + (p.exitValue() == 0 ? " successfully" : " with error" ));
} catch ( IOException | InterruptedException e) {
e.printStackTrace();
System.exit(1);
}
PrivateKey myPrivKey = null;
try {
byte[] keyArray = Files.readAllBytes(Paths.get(keyfile + ".der"));
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyArray);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
myPrivKey = keyFactory.generatePrivate(keySpec);
} catch (IOException | NoSuchAlgorithmException | InvalidKeySpecException e){
e.printStackTrace();
System.exit(1);
}
return myPrivKey;
}
Related
I'm trying to learn about rsa public key generations. After some researches I create an "simple" code that should return a public key but I don't know why, it doesn't. Can anyone tell me why and explaine it?
public static byte[] GetTokens(String paramString) {
StringTokenizer stringTokenizer = new StringTokenizer(paramString, ",");
byte[] arrayOfByte = new byte[stringTokenizer.countTokens()];
for (byte b1 = 0; stringTokenizer.hasMoreTokens(); b1++) {
arrayOfByte[b1] = Byte.parseByte(stringTokenizer.nextToken());
}
return arrayOfByte;
}
public static PublicKey GenPublicKey() throws Exception {
BufferedReader bufferedReader = new BufferedReader(new FileReader("input_text"));
try {
String str1 = bufferedReader.readLine();
String str2 = bufferedReader.readLine();
BigInteger bigInteger1 = new BigInteger(GetTokens(str1));
BigInteger bigInteger2 = new BigInteger(GetTokens(str2));
RSAPublicKeySpec rSAPublicKeySpec = new RSAPublicKeySpec(bigInteger1, bigInteger2);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(rSAPublicKeySpec);
return publicKey;
}
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown : " + e);
throw new IOException("Error reading key, ");
}
finally {
try {
bufferedReader.close();
} catch (Exception exception) {}
}
}
To testing it I wrote aleatory numbers on "input_text" file:
8,33
6,18
I will provide the code you need to generate a RSA public key:
import java.io.*;
import java.security.*;
import java.security.spec.*;
import java.util.*;
public class Hello {
public static void main(String[] args) throws NoSuchAlgorithmException {
// We generate an instance that allows to create private/public key pairs
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
// We use 1024 bits lenght
keyPairGenerator.initialize(2048);
// We generate key pair
KeyPair keyPair = keyPairGenerator.generateKeyPair();
// Original message
String originalMessage = "Hello";
// We obtain public key
Key publicKey = keyPair.getPublic();
// We convert the string in order to send the Key to the emitter
String publicKeyText = keyToString(publicKey);
System.out.println("Public key: " + publicKeyText);
}
private static String keyToString(Key publicKey) {
byte[] publicKeyBytes = publicKey.getEncoded();
String key = Base64.getEncoder().encodeToString(publicKeyBytes);
return key;
}
}
I'm new in Java and want to sign some data in c# and verify in Java with RSA and SHA512.
C#:
static string SignData(string message, RSAParameters privateKey)
{
byte[] signedBytes;
using (var rsa = new RSACryptoServiceProvider())
{
var encoder = new UTF8Encoding();
byte[] originalData = encoder.GetBytes(message);
rsa.ImportParameters(privateKey);
signedBytes = rsa.SignData(originalData, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);
rsa.PersistKeyInCsp = false;
}
return Convert.ToBase64String(signedBytes);
}
Java:
static boolean verifySignature512(String message, String sign, PublicKey publicKey) throws Exception {
MessageDigest digest = MessageDigest.getInstance("SHA-512");
byte[] contentDigest = digest.digest(message.getBytes(Charset.forName("UTF-8")));
Signature signature = Signature.getInstance("Sha512withRSA");
signature.initVerify(publicKey);
signature.update(contentDigest);
return signature.verify(Base64.getDecoder().decode(sign));
}
I used RSA and public and private keys. Java function always return false with no error or exception.
If I remove MessageDigest like below it starts working, Is it ok and secure?
static boolean verifySignature512(String message, String sign, PublicKey publicKey) throws Exception {
// MessageDigest digest = MessageDigest.getInstance("SHA-512");
// byte[] contentDigest = digest.digest(message.getBytes(Charset.forName("UTF-8")));
Signature signature = Signature.getInstance("Sha512withRSA");
signature.initVerify(publicKey);
signature.update(message.getBytes(Charset.forName("UTF-8")));
return signature.verify(Base64.getDecoder().decode(sign));
}
The signature verification on Java-side has to fail as you are using different hashing algorithms on both sides.
In C# you are using SHA1 ('HashAlgorithmName.SHA1') and the Java-part is using SHA512 ('Signature signature = Signature.getInstance("Sha512withRSA");').
The following code is using SHA1 as hash algorithm but you can easily change this (on all codelines :-) to SHA256 or SHA512.
The C#-code verifies the signature with the public key, the same public key (encoded as PEM) is used in the Java-code
for verification only.
Security warning: My example codes are using UNSECURE 512-bit RSA-keys that should not used in production.
There is not proper exception handling and you are using the padding 'RSASignaturePadding.Pkcs1' which should
NOT used anymore as well.
This is the output of my C#-code:
Should I use MessageDigest to verify a digital signature that signed in C#?
signedData: mU2bcCMEhG13xG9sKwhaA//dnw2+rbLkwz2737cNU5kb2EBenJIEJ+bA596XccCVKUKPanxMUFoVw2fl8HhCNw==
The data was verified.
That's the Java-output:
RSA instance: SHA1withRSA
The data was verified.
C#-code:
using System;
using System.Security.Cryptography;
using System.Text;
class RSACSPSample {
static void Main() {
try {
Console.WriteLine("Should I use MessageDigest to verify a digital signature that signed in C#?");
// Create a UnicodeEncoder to convert between byte array and string.
ASCIIEncoding ByteConverter = new ASCIIEncoding();
string message = "this is the important message to sign";
// get private and public key ### SAMPLE and UNSECURE 512 bit RSA keypair
var privateKey = "<RSAKeyValue><Modulus>mfgthqgvK5P6kP00ojzA68+tGMwjEacduojFSukazKPXrZ8Q5XjzfqgJmDQ3wcWe3hWK92O3z/tmAuN47KA0ZQ==</Modulus><Exponent>AQAB</Exponent><P>8VCRao0hZmIv5gVGFLqOD/7n6TQKlekA96U1QVzimKM=</P><Q>o1bchWA5ddDd59FED37QcrakoTXNoxRspFtsLDKEp1c=</Q><DP>ugF0VUE7wYNlkFP4VPoHjuTZNbRbhHn5uOmrRxqlvyk=</DP><DQ>XoGggC9Hr8pUyo9DIPAP7X+Ny5TU0Vm87m/TK9Ni+2s=</DQ><InverseQ>YqOHEP8dgCvz5Q8nhpQgdrKfdlmjkNAFxKF7j3pm09I=</InverseQ><D>mCpGy/rxS08e5iXn26LRQvvm5UfyLKMNZWmAGk2QF8cRGFB7dds/SI9wGTC9xyOoF4N2kWzYdLx+dYbR9lqwbQ==</D></RSAKeyValue>";
var publicKey = "<RSAKeyValue><Modulus>mfgthqgvK5P6kP00ojzA68+tGMwjEacduojFSukazKPXrZ8Q5XjzfqgJmDQ3wcWe3hWK92O3z/tmAuN47KA0ZQ==</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";
// Create a new instance of the RSACryptoServiceProvider class
RSACryptoServiceProvider RSAalg = new RSACryptoServiceProvider(512);
RSAalg.PersistKeyInCsp = false;
RSAalg.FromXmlString(privateKey);
RSAParameters rsaParameters = RSAalg.ExportParameters(true);
String signedData = SignData(message, rsaParameters);
Console.WriteLine("signedData: " + signedData);
// verify with xml-public key
RSAalg.FromXmlString(publicKey);
rsaParameters = RSAalg.ExportParameters(false);
bool verifiedData = VerifyData(message, signedData, rsaParameters);
// Verify the data and display the result to the
// console.
if (VerifyData(message, signedData, rsaParameters)) {
Console.WriteLine("The data was verified.");
}
else {
Console.WriteLine("The data does not match the signature.");
}
}
catch(ArgumentNullException) {
Console.WriteLine("The data was not signed or verified");
}
}
static string SignData(string message, RSAParameters privateKey)
{
byte[] signedBytes;
using (var rsa = new RSACryptoServiceProvider())
{
var encoder = new UTF8Encoding();
byte[] originalData = encoder.GetBytes(message);
rsa.ImportParameters(privateKey);
signedBytes = rsa.SignData(originalData, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);
rsa.PersistKeyInCsp = false;
}
return Convert.ToBase64String(signedBytes);
}
public static bool VerifyData(string message, string signedData, RSAParameters rsaParameters)
{
byte[] messageBytes;
byte[] signedBytes;
using (var rsa = new RSACryptoServiceProvider())
try
{
var encoder = new UTF8Encoding();
messageBytes = encoder.GetBytes(message);
signedBytes = Convert.FromBase64String(signedData);
rsa.ImportParameters(rsaParameters);
return rsa.VerifyData(messageBytes, new SHA1CryptoServiceProvider(), signedBytes);
}
catch(CryptographicException e) {
Console.WriteLine(e.Message);
return false;
}
}
}
Java-code:
import java.nio.charset.StandardCharsets;
import java.security.*;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
public class MainSha1 {
public static void main(String[] args) throws GeneralSecurityException {
System.out.println("Should I use MessageDigest to verify a digital signature that signed in C#?");
String message = "this is the important message to sign";
// this is a SAMPLE and UNSECURE RSA 512 bit key
String publicKeyPem = "-----BEGIN PUBLIC KEY-----\n" +
"MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAJn4LYaoLyuT+pD9NKI8wOvPrRjMIxGn\n" +
"HbqIxUrpGsyj162fEOV4836oCZg0N8HFnt4Vivdjt8/7ZgLjeOygNGUCAwEAAQ==\n" +
"-----END PUBLIC KEY-----";
String signedData = "HS4qvrXpqu97me7yDt9lWXp+QLjKMO8FY4kiUiGhMhi6KmXQXCtmcUWSbg0i+LXv7u5ueRiQNeBnu6UCbPhZLg==";
String rsaInstanceString = "SHA1withRSA";
System.out.println("RSA instance: " + rsaInstanceString);
PublicKey publicKey = getPublicKeyFromString(publicKeyPem);
boolean verifyData = verifyRsa(publicKey, rsaInstanceString, message.getBytes(StandardCharsets.UTF_8), Base64.getDecoder().decode(signedData));
if (verifyData = true) {
System.out.println("The data was verified.");
} else {
System.out.println("The data could NOT get verified.");
}
}
public static PublicKey getPublicKeyFromString(String key) throws GeneralSecurityException {
String publicKeyPEM = key;
publicKeyPEM = publicKeyPEM.replace("-----BEGIN PUBLIC KEY-----", "");
publicKeyPEM = publicKeyPEM.replace("-----END PUBLIC KEY-----", "");
publicKeyPEM = publicKeyPEM.replaceAll("[\\r\\n]+", "");
byte[] encoded = Base64.getDecoder().decode(publicKeyPEM);
KeyFactory kf = KeyFactory.getInstance("RSA");
PublicKey pubKey = (PublicKey) kf.generatePublic(new X509EncodedKeySpec(encoded));
return pubKey;
}
public static Boolean verifyRsa(PublicKey publicKey, String rsaInstanceString, byte[] messageByte,
byte[] signatureByte) throws SignatureException, NoSuchAlgorithmException, InvalidKeyException {
Signature publicSignature = Signature.getInstance(rsaInstanceString);
publicSignature.initVerify(publicKey);
publicSignature.update(messageByte);
return publicSignature.verify(signatureByte);
}
}
Im Trying to do my homework to create a class called Password that implements the Encryptable interface.
Im trying using RSA Algorythm.
I use some RSA code references from the Google and resulting my code below.
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Key;
import java.util.Arrays;
import javax.crypto.Cipher;
import java.util.Scanner;
public class Password
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
String password = sc.nextLine();
KeyPair keyPair = RSAKeyPair.keyPairRSA();
Key publicKey = keyPair.getPublic();
Key privateKey = keyPair.getPrivate();
System.out.println("Original: " + password);
byte[] encrypted = RSAEncryptDecrypt.encrypt(password, privateKey);
System.out.println("Encrypted: " + new String(encrypted));
byte[] decrypted = RSAEncryptDecrypt.decrypt(encrypted, publicKey);
System.out.println("Decrypted: " + new String(decrypted));
}
}
final class RSAConstants {
private RSAConstants() {
}
public static final String ALGORITHM = "RSA";
public static final int ALGORITHM_BITS = 2048;
}
class RSAKeyPair {
public static KeyPair keyPairRSA() {
KeyPairGenerator generator = null;
try {
generator = KeyPairGenerator.getInstance(RSAConstants.ALGORITHM);
} catch (Exception e) {
e.printStackTrace();
}
if (generator != null) {
generator.initialize(RSAConstants.ALGORITHM_BITS);
KeyPair keyPair = generator.genKeyPair();
return keyPair;
}
return null;
}
}
class RSAEncryptDecrypt {
public static byte[] encrypt(String original, Key privateKey) {
if (original != null && privateKey != null) {
byte[] bs = original.getBytes();
byte[] encData = convert(bs, privateKey, Cipher.ENCRYPT_MODE);
return encData;
}
return null;
}
public static byte[] decrypt(byte[] encrypted, Key publicKey) {
if (encrypted != null && publicKey != null) {
byte[] decData = convert(encrypted, publicKey, Cipher.DECRYPT_MODE);
return decData;
}
return null;
}
private static byte[] convert(byte[] data, Key key, int mode) {
try {
Cipher cipher = Cipher.getInstance(RSAConstants.ALGORITHM);
cipher.init(mode, key);
byte[] newData = cipher.doFinal(data);
return newData;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
My Input is:
InterstellarGalactica
All goes smooth except for the result of Encrypted Password
Resulting below
Original: InterstellarGalactica
Encrypted: Sªë/H?ù,X?U4??A???ìñáQ
÷? *?7*??d?'å?Ñ¡w °??? Pè???«{?D ÷??cB???'É »???qªîÉDë??~hb??z8?çÿ?hí?{mè?{*îèGê??WÅ{x??ï.5¼?úü;e??G?-F?shèn?FI
áh`UƒIàB!?åäô+ D<&"?)?????ß!??3ä?¬???â???<?¬Ü?{ #ó12B?òt?ƒòÆr²Ä·oHQ?ë?«ú?°?î? ?Äy?:X^<?
&:ryb\?¼
Decrypted: InterstellarGalactica
Why do it is became a meaningless character?
Is there anything wrong with my code?
Can you explain how to do it in proper way(if there is)?
Thanks in advance.
You are using RSA in the wrong way:
In RSA you use the public key for encryption and the private key for decryption.
You however use the private key for encryption and the public key for decryption:
byte[] encrypted = RSAEncryptDecrypt.encrypt(password, privateKey);
byte[] decrypted = RSAEncryptDecrypt.decrypt(encrypted, publicKey);
Additionally please never convert a byte[] that contains binary data to String. If you want to print binary data convert it for example to a hexadecimal or base64 String instead. Or if you want to print it as a number use BigInteger.
// output Base64 encoded
System.out.println(java.util.Base64.getEncoder().encode(encrypted));
// out hexadecimal (uses Apache commons codec library
System.out.println(org.apache.commons.codec.binary.Hex.encodeHexString(encrypted));
// out hexadecimal without external library)
System.out.println(new java.math.BigInteger(1, encrypted).toString(16))
// Output as large number (useful for manual RSA calculations)
System.out.println(new java.math.BigInteger(1, encrypted));
I've written code that generates the key pairs, but was wondering if there's any way to save and re-use them?
Here is the code that generaes the pair:
public static void main(String[] args) throws Exception {
String plainText = "Hello world";
Map<String, Object> keys = getRSAKeys();
PrivateKey privateKey = (PrivateKey) keys.get("private");
PublicKey publicKey = (PublicKey) keys.get("public");
System.out.println(privateKey.getEncoded());
System.out.println(publicKey.getEncoded());
String encrypted = encryptMessage(plainText, privateKey);
System.out.println(encrypted);
String decrypted = decryptMessage(plainText, publicKey, encrypted);
System.out.println(decrypted);
}
private static Map<String, Object> getRSAKeys() throws Exception {
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(2048);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
PublicKey publicKey = keyPair.getPublic();
Map<String, Object> keys = new HashMap<String, Object>();
keys.put("private", privateKey);
keys.put("public", publicKey);
return keys;
}
https://docs.oracle.com/javase/tutorial/security/apisign/step2.html -- good entry point.
Also here is some example code to do exactly what you want:
package mx.playground.security;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import javax.crypto.Cipher;
public class AppForStackOverflow {
public static final int KEY_SIZE = 2048;
public static final String PUBLIC_KEY_X509 = "C:\\workspace\\rsa-pair\\public-key";
public static final String PUBLIC_KEY_PKCS1 = "C:\\workspace\\rsa-pair\\public-key-pkcs1";
public static final String PUBLIC_KEY_PEM = "C:\\workspace\\rsa-pair\\public-key-pem";
public static final String PRIVATE_KEY_PKCS8 = "C:\\workspace\\rsa-pair\\private-key";
public static final String PRIVATE_KEY_PKCS1 = "C:\\workspace\\rsa-pair\\private-key-pkcs1";
public static final String PRIVATE_KEY_PEM = "C:\\workspace\\rsa-pair\\private-key-pem";
public static final String SIGNATURE_PATH = "C:\\workspace\\rsa-pair\\signature";
public static final String PRIVATE_KEY_PATH = PRIVATE_KEY_PKCS8;
public static final String PUBLIC_KEY_PATH = PUBLIC_KEY_X509;
public static void main(String[] args) {
generateRsaKeysPair();
encryptDecryptTest();
// symmetric encryption example, use it to store your Private Key in safe manner
String message = "test message";
String rightPass = "0123456789ABCDEF"; // for AES password should be at least 16 chars
String wrongPass = "zzz";
byte[] encryptedMessage = symmetricEncrypt(message.getBytes(), rightPass);
System.out.print(new String(encryptedMessage));
byte[] decryptedMessage = symmetricDecrypt(encryptedMessage, rightPass);
System.out.println(new String(decryptedMessage));
}
public static void generateRsaKeysPair() {
try {
KeyPairGeneratorJdk kpg = new KeyPairGeneratorJdk(KEY_SIZE, "RSA");
PublicKey publicKey = kpg.getPublicKey();
PrivateKey privateKey = kpg.getPrivateKey();
save(PUBLIC_KEY_PATH, publicKey.getEncoded());
save(PRIVATE_KEY_PATH, privateKey.getEncoded());
} catch (Exception e) {
throw new RuntimeException("Failed to execute generateRsaKeysPair()", e);
}
}
public static void encryptDecryptTest() {
try {
byte[] privateKeyBytes = read(PRIVATE_KEY_PATH);
byte[] publicKeyBytes = read(PUBLIC_KEY_PATH);
KeyFactory kf = KeyFactory.getInstance("RSA");
PKCS8EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(privateKeyBytes);
PrivateKey privateKey = kf.generatePrivate(privateKeySpec);
X509EncodedKeySpec spec = new X509EncodedKeySpec(publicKeyBytes);
PublicKey publicKey = kf.generatePublic(spec);
Cipher cipher = Cipher.getInstance("RSA");
// doing encryption
String message = "test message";
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] encodedMessage = cipher.doFinal(message.getBytes("UTF-8"));
System.out.println("ENCRYPTED: " + new String(encodedMessage));
// doing decryption
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] decodedMessage = cipher.doFinal(encodedMessage);
System.out.println("DECRYPTED: " + new String(decodedMessage));
} catch (Exception e) {
throw new RuntimeException("Failed to execute encryptDecryptTest()", e);
}
}
private static void save(String path, byte[] data) {
try {
File file = new File(path);
file.getParentFile().mkdirs();
try (FileOutputStream fos = new FileOutputStream(file)){
fos.write(Base64.getEncoder().encode(data));
fos.flush();
};
} catch (IOException e) {
throw new RuntimeException("Failed to save data to file: " + path, e);
}
}
private static byte[] read(String path) {
try {
return Base64.getDecoder().decode(Files.readAllBytes(new File(path).toPath()));
} catch (IOException e) {
throw new RuntimeException("Failed to read data from file: " + path, e);
}
}
/*
* Use this to encrypt your private key before saving it to disk
*/
public static byte[] symmetricEncrypt(byte[] data, String password) {
try {
SecretKeySpec secretKey = new SecretKeySpec(password.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, secretKey);
byte[] result = cipher.doFinal(data);
return result;
} catch (Exception e) {
throw new RuntimeException("Failed to execute symmetricEncrypt()", e);
}
}
public static byte[] symmetricDecrypt(byte[] data, String password) {
try {
SecretKeySpec secretKey = new SecretKeySpec(password.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, secretKey);
byte[] result = cipher.doFinal(data);
return result;
} catch (Exception e) {
throw new RuntimeException("Failed to execute symmetricEncrypt()", e);
}
}
}
We have to encrypt our data with HMAC-SHA256 that needs randomly generated salt. We are generating the salt this way:
public String generateSalt() throws Exception
{
KeyGenerator keyGen;
String salt = null;
try
{
keyGen = KeyGenerator.getInstance( "HmacSHA256" );
keyGen.init( 128 );
SecretKey key = keyGen.generateKey();
byte[] encodedKey = key.getEncoded();
salt = Base64.encodeBase64String( key.getEncoded() );
LOG.info( "Salt : " + salt );
}
catch ( NoSuchAlgorithmException )
{
e.printStackTrace();
throw e;
}
return salt;
}
According to our test this salt generation part is right. I have issue with the next part:
Now I have to write this salt in binary format in a file ( say named as pie_raw) and that's been done as:
private void writeToFile( byte[] saltBytes, String fileName ) throws FileNotFoundException, IOException
{
DataOutputStream out = new DataOutputStream( new FileOutputStream( enviro.getOutputFilePath()
+ fileName ) );
out.write( saltBytes );
out.close();
LOG.info( " Raw file created : " + enviro.getOutputFilePath() + fileName );
}
And then, I have to encrypt this salt with a supplied public RSA key in ".pem" and for Java implementation, the cipher will be "RSA/ECB/OAEPWithSHA1AndMGF1Padding". And finally the binary ciphertext should be written to a file named "pie_key". This part has been implemented this way:
private byte[] encryptSalt( String salt ) throws Exception
{
byte[] cipheredKey = null;
try
{
String keyString= readKeyFile( enviro.getPublicKeyFile() );
byte[] pem = pemToDer(keyString);
PublicKey publicKey = derToPublicKey(pem);
//PublicKey publicKey = getPublicKey( enviro.getPublicKeyFile() );
// Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
Cipher rsaCipher = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding");
rsaCipher.init( Cipher.ENCRYPT_MODE, publicKey );
cipheredKey = rsaCipher.doFinal( salt.getBytes( "UTF-8" ) );//"UTF-8"
LOG.info( "Cyphered key : " + cipheredKey.toString() );
}
catch ( IOException | GeneralSecurityException e )
{
e.printStackTrace();
throw e;
}
return cipheredKey;
}
static String readKeyFile( String path )
throws IOException
{
String line = null;
try (BufferedReader br =
new BufferedReader( new FileReader( path ) ))
{
StringBuilder sb = new StringBuilder();
line = br.readLine();
while ( line != null )
{
sb.append( line );
sb.append( "\n" );
line = br.readLine();
}
return sb.toString();
}
}
public static byte[] pemToDer( String pemKey ) throws GeneralSecurityException
{
String[] parts = pemKey.split( "-----" );
return DatatypeConverter.parseBase64Binary( parts[ parts.length / 2 ] );
}
public static PublicKey derToPublicKey( byte[] asn1key ) throws GeneralSecurityException
{
X509EncodedKeySpec spec = new X509EncodedKeySpec( asn1key );
KeyFactory keyFactory = KeyFactory.getInstance( "RSA" );
return keyFactory.generatePublic( spec );
}
Writing this encrypted salt to a file named as "pie_key" in binary format by calling the "writeToFile" method above.
Now the content of the file "pie_key" should match the out put of the cmd :
openssl rsautl -encrypt -pubin -inkey wrap_pie_key_rsa.pem -oaep -in pie_key.raw -out pie_key
But whatever I tried ( you may find some signs of the ways, I tried ) did not work means that the final binary-encrypted-salt did not match with the output of openssl cmd.
Any idea what I am doing wrong?
I am using Java 7. And the .pem (partial) looks like
-----BEGIN PUBLIC KEY-----
MIIBIjANBgk345iG9w0BAQEFAA54328AMIIBCgKCAQEAt4GLJGPmvYdxwwAe59n3
.
.
.
.
7QIDNQAB
-----END PUBLIC KEY-----
Thanks in advance.
First of all, as Artjom already mentioned, the padding for OAEP or PKCS#1 v1.5 compatible padding is randomized. So even if you encrypt the same salt multiple times you would not get the same value. You can only decrypt the result to see if encryption succeeded.
Furthermore, you say you need a binary salt, but you first encode the salt to base64. It's unlikely that your encryption should contain an encoded salt. Maybe you need to encode the output of the encryption, not the salt.
The spurious encoding happens in the following line:
salt = Base64.encodeBase64String( key.getEncoded() );
Finally, although a new HMAC key generally consists of fully random bytes, I would say that it is not the right way to generate a salt. Instead just use:
SecureRandom rngForSalt = new SecureRandom();
byte[] salt = new byte[SALT_SIZE];
rngForSalt.nextBytes(salt);
Note too that the Bouncy Castle lightweight API (i.e. calling org.bouncycastle functionality directly) contains a PEM codec. No need to program or hack that yourself.
Try this Java 8 code. Bouncy castle provider classes required (no need to register the provider, this is just for the PEM handling).
package nl.maartenbodewes.stackoverflow;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.file.Files;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import org.bouncycastle.util.io.pem.PemObject;
import org.bouncycastle.util.io.pem.PemReader;
import org.bouncycastle.util.io.pem.PemWriter;
public class GenerateAndWrapHMACKey {
public static SecretKey generateHMACKey() throws Exception {
final KeyGenerator keyGen;
try {
keyGen = KeyGenerator.getInstance("HmacSHA256");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("HMAC KeyGeneration should be available");
}
keyGen.init(128);
SecretKey key = keyGen.generateKey();
return key;
}
public static void writeToFile(SecretKey key, String filename)
throws IOException {
// file handling probably should be in a separate class
Files.write((new File(filename)).toPath(), key.getEncoded());
}
public static RSAPublicKey readRSAPublicKey(String filename) throws IOException, InvalidKeySpecException {
try (PemReader reader = new PemReader(new FileReader(filename))) {
PemObject pemObject = reader.readPemObject();
KeyFactory kf;
try {
kf = KeyFactory.getInstance("RSA");
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("RSA key factory not available", e);
}
KeySpec keySpec = new X509EncodedKeySpec(pemObject.getContent());
try {
return (RSAPublicKey) kf.generatePublic(keySpec);
} catch (ClassCastException e) {
throw new InvalidKeySpecException("That's no RSA key", e);
}
}
}
public static byte[] wrapKey(Key key, RSAPublicKey wrappingKey) throws InvalidKeyException, IllegalBlockSizeException {
Cipher rsaWrapper;
try {
rsaWrapper = Cipher.getInstance("RSA/ECB/OAEPWithSHA1AndMGF1Padding");
rsaWrapper.init(Cipher.WRAP_MODE, wrappingKey);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException e) {
throw new RuntimeException("RSA OAEP should be available for RSA public key", e);
}
return rsaWrapper.wrap(key);
}
public static void main(String[] args) throws Exception {
// we need an RSA PEM key first I guess :)
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024, new SecureRandom());
KeyPair kp = kpg.generateKeyPair();
String publicKeyFilename = "rsa_pub.pem";
try (PemWriter pemWriter = new PemWriter(new FileWriter(publicKeyFilename))) {
pemWriter.writeObject(new PemObject("PUBLIC KEY", kp.getPublic().getEncoded()));
}
RSAPublicKey wrappingRSAPublicKey = readRSAPublicKey(publicKeyFilename);
SecretKey hmacKey = generateHMACKey();
byte[] wrappedKey = wrapKey(hmacKey, wrappingRSAPublicKey);
System.out.println(Base64.getEncoder().encodeToString(wrappedKey));
}
}