Good day,
There is another third party that need my web application to send them some data in encrypt format. Thus they send me some guide to do so, however, I am not familiar with it, I am trying to google around but looks like I am google wrong way.
The guide is something as follow:
Run openssl command to generate a privatekey:
openssl ecparam -name prime256v1 -genkey -out myprivate.pem
After run this command, I output a priv.pem file, and I saw inside got some key end with '==', which is as follow:
-----BEGIN EC PARAMETERS-----
BggqhkjOPQMBBw==
-----END EC PARAMETERS-----
-----BEGIN EC PRIVATE KEY-----
MHcCAQEEILefWfeuZOgnbDlxpwo3uQ2xQXfhXHUPTS+vKzvVZdCToAoGCCqGSM49
AwEHoUQDQgAE4MeQspGRJ1qdpweBfiaT5P84alZdga1f7mSpa5HqXTH58u0ZWJUQ
J7ToU/bUOPITh4FX07AV6wrgFCmwtUenDQ==
-----END EC PRIVATE KEY-----
Second one is run openssl command to generate the public key, and then send them:
openssl ec -in myprivate.pem -pubout -out mypublic.pem
Convert the private key to pkcs8 format:
openssl pkcs8 -topk8 -nocrypt -in myprivate.pem -out mypkcs8.pem
The third party will give me a public key in string format, then ask me to generate a secret key, and provide me some java code as follow:
first is to generate secret key and second one is encrypt:
public static SecretKey generateSharedSecret(PrivateKey privateKey,
PublicKey publicKey) {
try {
KeyAgreement keyAgreement = KeyAgreement.getInstance( "ECDH" );
keyAgreement.init( privateKey );
keyAgreement.doPhase( publicKey, true );
SecretKeySpec key = new SecretKeySpec(
keyAgreement.generateSecret( ), "AES" );
return key;
} catch ( Exception e ) {
// TODO Auto-generated catch block
e.printStackTrace( );
return null;
}
}
public static String encryptString(SecretKey key, String plainText) {
try {
String myIv = "Testing # IV!";
byte[] iv = myIv.getBytes( "UTF-8" );
IvParameterSpec ivSpec = new IvParameterSpec( iv );
Cipher cipher = Cipher.getInstance( "AES / CBC / PKCS5Padding" );
byte[] plainTextBytes = plainText.getBytes( "UTF-8" );
byte[] cipherText;
cipher.init( Cipher.ENCRYPT_MODE, key, ivSpec );
cipherText = new byte[cipher.getOutputSize( plainTextBytes.length )];
int encryptLength = cipher.update( plainTextBytes, 0,
plainTextBytes.length, cipherText, 0 );
encryptLength += cipher.doFinal( cipherText, encryptLength );
return bytesToHex( cipherText );
} catch ( Exception e ) {
e.printStackTrace( );
return null;
}
}
and also the bytes to hex string method:
public static String bytesToHex(byte[] byteArray) {
StringBuffer hexStringBuffer = new StringBuffer( );
for ( int i = 0; i < byteArray.length; i++ ) {
hexStringBuffer.append( String.format( "%02X", byteArray[ i ] ) );
}
return hexStringBuffer.toString( );
}
I have self gen a private key and also a public key by using openssl command, but the 4th step telling me that they will give me a public key as well, thus I am not understand, which public key should I use.
And also, how can I convert a String into java PrivateKey and PublicKey object?
* add on *
I try to convert the der file to java PublicKey object, it looks work. Before this, I convert the pem to der using openssl command:
openssl pkey -pubin -in ecpubkey.pem -outform der -out ecpubkey.der
Here is the java code:
File f = new File("/home/my/Desktop/key/ecpubkey.der");
FileInputStream fis = new FileInputStream(f);
DataInputStream dis = new DataInputStream(fis);
byte[] keyBytes = new byte[(int) f.length()];
dis.readFully(keyBytes);
dis.close();
KeyFactory fact = KeyFactory.getInstance("EC");
PublicKey theirpub = fact.generatePublic(new X509EncodedKeySpec(keyBytes));
However, I am hitting java.security.spec.InvalidKeySpecException: java.io.IOException: insufficient data when I try to convert der file to java PrivateKey object, the following is what I did:
openssl ecparam -name prime256v1 -genkey -out priv.pem
openssl pkcs8 -topk8 -nocrypt -in priv.pem -outform der -out priv.der
And the following is my java code:
File f2 = new File("/home/my/Desktop/key/priv.der");
FileInputStream fis2 = new FileInputStream(f2);
DataInputStream dis2 = new DataInputStream(fis2);
byte[] keyBytes2 = new byte[(int) f.length()];
dis2.readFully(keyBytes2);
dis2.close();
KeyFactory fact2 = KeyFactory.getInstance("EC");
PrivateKey pKey = fact2.generatePrivate( new PKCS8EncodedKeySpec(keyBytes2) ); // this line hit insufficient data
Diffie-Hellman is well-explained in wikipedia -- and probably some of the hundreds of Qs here, and crypto.SX and security.SX, about it, but I can't easily find which. In brief:
you generate a keypair, keep your privatekey, and provide your publickey to the other party
the other party does the same thing (or its reflection): generate a keypair, keep their privatekey, and provide their publickey to you
you use your privatekey and their publickey to compute the 'agreement' value
they similarly use their privatekey and your publickey to compute the same 'agreement' value. This is also called a shared secret, because you and the other party know it, but anyone eavesdropping on your traffic does not.
The 'provide' in that synopsis omits a lot of very important details. It is vital that when you provide your publickey to the other party they actually get your publickey and not a value altered or replaced by an adversary, and similarly when they provide their publickey to you it is vital you get the real one and not a modified or fake one. This is where actual DH systems mostly break down, and the fact you mention none of the protections or complications needed here suggests your scheme will be insecure and easily broken -- if used for anything worth stealing.
Note you should NEVER disclose or 'send' your privatekey to anyone, and they should similarly not disclose theirs. That's the main basis for public-key (or 'asymmetric') cryptography to be of any value or use at all.
There are numerous ways that keys can be represented, but only some are relevant to you.
Public keys are often represented either in
the ASN.1 structure SubjectPublicKeyInfo defined in X.509 and more conveniently in PKIX, primarily in rfc5280 #4.1 and #4.1.2.7 and rfc3279 2.3, encoded in DER, which has the limitation that many of the bytes used in this encoding are not valid characters and cannot be correctly displayed or otherwise manipulated and sometimes not transmitted or even stored; or
that same ASN.1 DER structure 'wrapped' in 'PEM' format, which converts the troublesome binary data to all displayable characters in an easily manipulable form. PEM format was originally created for a secure-email scheme call Privacy Enhanced Mail which has fallen by the wayside, replaced by other schemes and technologies, but the format it defined is still used. The publickey PEM format was recently re-standardized by rfc7468 #13 (which as you see referenced rfc5280).
OpenSSL supports both of these, but the commandline utility which you are using mostly defaults to PEM -- and since you need to convey your key to 'them', and they need to convey their key to you, PEM may well be the most reliable and/or convenient way of doing so. (Although other formats are possible, if you and they agree -- and if they require something else you'll have to agree for this scheme to work at all.)
Java directly supports only DER, thus assuming you receive their publickey in SPKI PEM, to use it in Java you need to convert it to DER. You can either do this in OpenSSL
openssl pkey -pubin -in theirpub.pem -outform der -out theirpub.der
and then read the DER into a Java crypto KeyFactory:
byte[] theirpubder = Files.readAllBytes(Paths.get(whatever));
KeyFactory fact = KeyFactory.getInstance("EC");
PublicKey theirpub = fact.generatePublic(new X509EncodedKeySpec(theirpubder));
// can downcast to ECPublicKey if you want to be more specific
Alternatively you can have Java convert the PEM which isn't too hard; there are several variations but I like:
String theirpubpem = new String(Files.readAllBytes(Paths.get(whatever)));
// IN GENERAL letting new String(byte[]) default the charset is dangerous, but PEM is OK
byte[] theirpubder = Base64.getMIMEDecoder().decode(theirpubpem.replaceAll("-----[^\\n]*\\n","") );
// continue as for DER
For private keys
there are significantly more representations, but only one (or two-ish) that Java shares with OpenSSL. Since you only need to store the private key locally and not 'send' it, PEM may not be needed; if so you can just add -outform der to your pkcs8 -topk8 -nocrypt command, adjusting the name appropriately, and read the result directly in a Java KeyFactory in the same fashion as above except with PKCS8EncodedKeySpec and generatePrivate and [EC]PrivateKey. If you do want to store it in (PKCS8-clear) PEM, you can also combine the above.
Using the DH agreement value directly as a symmetric cipher (e.g. AES) key is nonstandard and generally not considered good practice, although for ECDH with prime256v1 (aka secp256r1 or P-256) it is technically possible. AFAIK all good standards use a key-derivation step (aka Key Derivation Function or KDF) in between. Since you haven't shown us their 'guide' I can't say if this is correct -- for at least small values of correct.
To be sure you know, using CBC with a fixed IV more than once for the same key (which in this case is the same DH result) is insecure. I assume 'Testing' means you plan to replace it with something better.
Also FYI you don't need to use the full complication of the Cipher.init,update,doFinal API. When the data is small enough to fit in memory, as here, you can just do:
cipher.init(ENCRYPT_MODE, key, parms);
byte[] encrypted = cipher.doFinal (plainbytes);
// or since you want to hexify it
... bytesToHex (cipher.doFinal (plainbytes)) ...
Finally because Java byte is signed, your bytesToHex will output almost exactly half of all bytes with FFFFFF prefixed. This is very unusual, and phenomenally ugly, but again I don't know if it is 'correct' for you.
Base on dave_thompson_085 explanation and code, I manage to create my java PublicKey and Privatekey with following:
public static PublicKey getPublicKey(String filename) throws IOException, GeneralSecurityException {
String publicKeyPEM = getKey(filename);
return getPublicKeyFromString(publicKeyPEM);
}
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 PublicKey getPublicKeyFromString(String key) throws IOException, GeneralSecurityException {
String publicKeyPEM = key;
publicKeyPEM = publicKeyPEM.replace("-----BEGIN PUBLIC KEY-----\n", "");
publicKeyPEM = publicKeyPEM.replace("-----END PUBLIC KEY-----", "");
BASE64Decoder b = new BASE64Decoder();
byte[] encoded = b.decodeBuffer(publicKeyPEM);
KeyFactory kf = KeyFactory.getInstance("EC");
PublicKey pubKey = (PublicKey) kf.generatePublic(new X509EncodedKeySpec(encoded));
return pubKey;
}
and this is for private key
public static PrivateKey getPrivateKey(String filename) throws IOException, GeneralSecurityException {
String privateKeyPEM = getKey(filename);
return getPrivateKeyFromString(privateKeyPEM);
}
public static PrivateKey getPrivateKeyFromString(String key) throws IOException, GeneralSecurityException {
String privateKeyPEM = key;
privateKeyPEM = privateKeyPEM.replace("-----BEGIN PRIVATE KEY-----\n", "");
privateKeyPEM = privateKeyPEM.replace("-----END PRIVATE KEY-----", "");
BASE64Decoder b = new BASE64Decoder();
byte[] encoded = b.decodeBuffer(privateKeyPEM);
KeyFactory kf = KeyFactory.getInstance("EC");
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(encoded);
PrivateKey privKey = (PrivateKey) kf.generatePrivate(keySpec);
return privKey;
}
Many thanks to #dave_thompson_085 explanation.
Our C# version of this seemingly simple and standard java RSA encryption code is NOT generating the same result. Help?
NOTE: the java code uses a DER file, so we had to firstly convert it to PEM format (via openssl)
openssl rsa -inform DER -outform PEM -in FOO.der -out FOO.pem
and then that to XML (via BouncyCastle). Specifically:
using (var reader = new StreamReader(PrivateKeyPemFile)) { text =
reader.ReadToEnd(); } string xmlpem = RsaKeyConverter.PemToXml(text);
What are we doing wrong here? (Was it our key conversion? Or is there a CspParameter setting that will magically make this equivalent? Or...)
JAVA code
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
KeySpec keySpec = new PKCS8EncodedKeySpec(keyRawBytes);
java.security.Key key = keyFactory.generatePrivate(keySpec);
javax.crypto.Cipher cipher = javax.crypto.Cipher.getInstance("RSA");
cipher.init(1, key);
encryptedBytes = cipher.doFinal(data);
C# code
RSACryptoServiceProvider cryptoServiceProvider = new RSACryptoServiceProvider();
cryptoServiceProvider.FromXmlString(pemXmlString);
var encryptedBytes = rsa.Encrypt(data, false);
I am trying to generate an encrypted private key and CSR using Java in Matlab. Matlab adds some minor complexity, but this is mostly a Java problem. I start with a private key:
java.security.Security.addProvider(org.bouncycastle.jce.provider.BouncyCastleProvider());
keyGen = java.security.KeyPairGenerator.getInstance('RSA', 'BC');
keyGen.initialize(2048, java.security.SecureRandom());
keypair = keyGen.generateKeyPair();
privateKey = keypair.getPrivate();
If I encrypt the key and output it as PEM:
m=org.bouncycastle.openssl.PKCS8Generator.PBE_SHA1_3DES;
encryptorBuilder = org.bouncycastle.openssl.jcajce.JceOpenSSLPKCS8EncryptorBuilder(m);
encryptorBuilder.setRandom(java.security.SecureRandom());
encryptorBuilder.setPasssword(password);
oe = encryptorBuilder.build();
gen = org.bouncycastle.openssl.jcajce.JcaPKCS8Generator(privateKey,oe);
privKeyObj = gen.generate();
fos = java.io.FileWriter('private.pem');
pem = org.bouncycastle.openssl.jcajce.JcaPEMWriter(fos);
pem.writeObject(privKeyObj);
pem.flush();
fos.close();
I get a perfectly good key. The problem is that I want to use the key with jdbc, so I need a DER formatted pk8 key. I cannot figure out how to get this out of BouncyCastle. A kludge workaround that succeeds:
textWriter = java.io.StringWriter();
pem = org.bouncycastle.openssl.jcajce.JcaPEMWriter(textWriter);
pem.writeObject(privateKey);
pem.flush();
thekey = char(textWriter.toString());
cmd = ['echo "' thekey '"|openssl pkcs8 -topk8 -out private.pk8 -inform PEM -outform DER -passout pass:' password];
system(cmd);
Now, obviously this exposes both the unencrypted private key and the password. I've tried all manner of things to coerce privKeyObj to DER, but they typically leave me with:
$openssl pkcs8 -inform DER -outform PEM -in private.pk8 -out private.pem
Error decrypting key
140735211835472:error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag:tasn_dec.c:1201:
140735211835472:error:0D06C03A:asn1 encoding routines:ASN1_D2I_EX_PRIMITIVE:nested asn1 error:tasn_dec.c:765:
140735211835472:error:0D08303A:asn1 encoding routines:ASN1_TEMPLATE_NOEXP_D2I:nested asn1 error:tasn_dec.c:697:Field=version, Type=PKCS8_PRIV_KEY_INFO
The intent of this code is to generate a CSR on the end user's machine which I then sign, and which is encrypted with MAC address of the machine (and a salt), so that the program will only run on the authorized machine, and only authorized machines will be able to access my PostgreSql database.
Suggestions?
I figured it out. In my original code, I had used BcPKCS12PBEOutputEncryptorBuilder. Wrong! The correct call is to JcePKCSPBEOutputEncryptorBuilder. The correct code (in MATLAB, but converting to Java is simple) is:
java.security.Security.addProvider(org.bouncycastle.jce.provider.BouncyCastleProvider());
keyGen = java.security.KeyPairGenerator.getInstance('RSA', 'BC');
keyGen.initialize(2048, java.security.SecureRandom());
keypair = keyGen.generateKeyPair();
privateKey = keypair.getPrivate();
builder=org.bouncycastle.pkcs.jcajce.JcaPKCS8EncryptedPrivateKeyInfoBuilder(privateKey);
m=org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers.pbeWithSHAAnd3_KeyTripleDES_CBC;
encryptorBuilder = org.bouncycastle.pkcs.jcajce.JcePKCSPBEOutputEncryptorBuilder(m);
password = 'test';
outputBuilder = encryptorBuilder.build(password);
privKeyObj = builder.build(outputBuilder);
fos = java.io.FileOutputStream('testkey.pk8');
fos.write(privKeyObj.getEncoded());
fos.flush();
fos.close();
This generates a DER formatted PCS#8 file.
openssl pkcs8 -inform DER -outform PEM -in testkey.pk8 -out testkey.pem
Now returns the PEM private key. To read the key:
myPath = java.nio.file.Paths.get(pwd,'testkey.pk8');
encodedKey = java.nio.file.Files.readAllBytes(myPath);
privKeyObj =org.bouncycastle.pkcs.PKCS8EncryptedPrivateKeyInfo(encodedKey);
cp=org.bouncycastle.openssl.jcajce.JcaPEMKeyConverter();
cp.setProvider('BC');
decryptorBuilder = org.bouncycastle.pkcs.jcajce.JcePKCSPBEInputDecryptorProviderBuilder();
inputBuilder = decryptorBuilder.build(password);
info = privKeyObj.decryptPrivateKeyInfo(inputBuilder);
decodedKey=cp.getPrivateKey(info);
Note that in MATLAB, you don't need to declare the type of the returned object, and you don't need to put "new" in front of a constructor.
I am trying to encrypt a text file using a .pfx certificate file using :
public void EncryptUsingPublicKey(File in, File out, File publicKeyFile) throws IOException, GeneralSecurityException {
byte[] encodedKey = new byte[(int)publicKeyFile.length()];
new FileInputStream(publicKeyFile).read(encodedKey);
// create public key
X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encodedKey);
KeyFactory kf = KeyFactory.getInstance("RSA");
PublicKey pk = kf.generatePublic(publicKeySpec);
FileInputStream is = new FileInputStream(in);
Cipher pkCipher = Cipher.getInstance("RSA");
pkCipher.init(Cipher.ENCRYPT_MODE, pk);
CipherOutputStream os = new CipherOutputStream(new FileOutputStream(out), pkCipher);
copy(is, os);
os.close();
}
I have two problems:
Where should I store the .pfx file on the device?
Is this function correct?
I don't think that your code will work. PFX files are internally AFAIR PKCS#12 files with can contain multiple certificates and keys. The X509EncodedKeySpec you are using requires to have exactly one certificate in a .CER file (DER/binary format).
Therefore you have the following two options:
Extract the certificate from the PFX file as CER file (e.g. with the GUI tool portecle) or
Try to read the PFX file as a PKCS#12 KeyStore at it is presented here: PKCS12 Java Keystore from CA and User certificate in java
In the end you can include the PFX/CER file as resource into your andoid app: Load file from resource
I'm trying to encrypt some binary data in Java with a public key as described on this useful page:
http://www.junkheap.net/content/public_key_encryption_java
As directed by the page, I created public and private keys using the commands:
openssl genrsa -aes256 -out private.pem 2048
openssl rsa -in private.pem -pubout -outform DER -out public.der
Now I save encrypt some data with a small program:
public class Rsa {
public static void main(String[] args) throws Exception, IOException {
File keyFile = new File("public.der");
byte[] encodedKey = new byte[(int) keyFile.length()];
new FileInputStream(keyFile).read(encodedKey);
X509EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(encodedKey);
KeyFactory kf = KeyFactory.getInstance("RSA");
PublicKey pk = kf.generatePublic(publicKeySpec);
Cipher rsa = Cipher.getInstance("RSA");
rsa.init(Cipher.ENCRYPT_MODE, pk);
FileOutputStream fileOutputStream = new FileOutputStream(
"encrypted.rsa");
OutputStream os = new CipherOutputStream(fileOutputStream, rsa);
byte[] raw = new byte[245];
raw[0] = 4;
os.write(raw);
os.flush();
os.close();
}
}
The above code works, but when I change the size of the byte array to 246, it produces a zero-length file!
What am I doing wrong?
CipherOutputStream tends to swallow exceptions generated by the Cipher and OutputStream objects it wraps. The Sun RSA implementation will not encrypt more than than M-11 bytes, where M is the length in bytes of the modulus. This is true for the default PKCS1Padding, which is what you should always use unless you really know what you are doing. You can specify NoPadding and thereby get the full M bytes.
RSA is not the correct choice for encrypting bulk data. The generally accepted method for encrypting data with RSA is to generate a random symmetric session key K. e.g. an AES key, encrypt the data with the symmetric algorithm with K, then encrypt K using the RSA keys of all the receipients.