loading a certificate from keystore - java

Load a certificate and keys from keystore which is password protected and then use it for cert verification and digital signing

To read the certificate is really trivial.
CertificateFactory factory = CertificateFactory.getInstance("X.509");
X509Certificate certificate = (X509Certificate) factory.generateCertificate(new FileInputStream("file.pem"));
This is with standard APIs (in try/catch) etc and you have loaded your certificate.
Now the toString method of certificate is not suitable for you since it just captures the "user's" view of the certificate e.g. you would use it for println for instance
Can't you send the certificate object itself?
Not sure what your server expects so you can look into the various methods of certificate
X509Certificate

I use this code
PEMReader pr=new PEMReader(new StringReader(trust_certs));
KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
trustStore.load(null, null);
Object o;
int i=0;
while((o=pr.readObject())!=null){
if(o instanceof X509Certificate){
i++;
X509Certificate c=(X509Certificate)o;
trustStore.setCertificateEntry(Integer.toString(i), c);
}
}
http://www.bouncycastle.org/docs/docs1.6/org/bouncycastle/openssl/PEMReader.html

A pem file is read as any other text file. Read the Java tutorial about IO (and concentrate on character streams, since a pem file contains text, and on File IO, since this is what you want to do)

Related

How do you convert PKCS#12 String to Certificate and PrivateKey?

I am receiving the following String from a certificate stored in Azure Key Vault. I am using the Secret API in order to retrieve both the certificate and the private key related to this cert.
Initially the certificate was uploaded using a .pfx file to Azure Key vault. Now I need to create a Certificate and a PrivateKey to allow client authentication to a 3rd party system and I am using the given String retrieved from the API, however I am note sure how to get around that in Java.
I took some hints from this link in C# however I am pretty certain that this method doesn't work like that in Java. In particular an X509Certificate or a Certificate in general doesn't hold any information about the PrivateKey in Java, unlike C#, and I am not sure how to extract that information from given String in Java.
This works as expected to retrieve the certificate from the String retrieved from the API
String secret = azureSecret.getValue();
byte[] certkey = Base64.getDecoder().decode(secret);
ByteArrayInputStream inputStream = new ByteArrayInputStream(certkey);
CertificateFactory cf = CertificateFactory.getInstance("X.509");
Certificate cert = cf.generateCertificate(inputStream);
The azureSecret.getValue() format is like the following however I am not sure how to get PrivateKey out of the given String
MIIKvgIBaaZd6Euf3EYwYdHrIIKYzCC...
YES, Java X509Certificate and Certificate is only the certificate. Instead use KeyStore which can contain multiple entries each of which is either a 'trusted' certificate (for someone else), or a privatekey plus certificate plus other chain cert(s) (if applicable) for yourself, or (not relevant here) a 'secret' (symmetric) key. PKCS12 is supported as one type of KeyStore along with others not relevant here, so after the base64-decoding you already have do something like:
KeyStore ks = KeyStore.getInstance("PKCS12");
ks.load(inputstreamfromvaultvalue, password);
// then
PrivateKey pkey = (PrivateKey) ks.getKey(alias, password);
// and
Certificate cert = ks.getCertificate(alias); // if you only need the leaf cert
// or
Certificate[] chain = ks.getCertificateChain(alias); // usually
But if you want to do client authentication in TLS/SSL (including HTTPS), you give the JSSE KeyManager the whole keystore object not the individual pieces (privatekey and certificates). Similarly to verify the peer in TLS/SSL, you give TrustManager a keystore containing trusted certificates, usually root CAs and often defaulted to a built-in set of public root CAs.

Rename JKS alias with java programmatically

I would like to know how can I rename an alias of a keystore, programmatically in java, not using keytool.
I have my java.security.KeyStore object, containing an certain alias. How can I rename it?
The KeyStore API does not provide a rename operation for aliases. But what you can do is:
Save the content (key pair, certificates) of the keystore entry that you want to rename.
Delete the entry.
Create a new entry with the saved content and the new alias.
As Java code:
Key privateKey = keyStore.getKey(alias, password.toCharArray());
Certificate[] certs = keyStore.getCertificateChain(alias);
keyStore.setKeyEntry(newAlias, privateKey, password.toCharArray(), certs);
keyStore.deleteEntry(alias);
Of course this does not work if the private key is stored on a hardware device (smartcard or HSM) and therefore is not readable.
If the keystore entry contains a trusted certificate, the code looks a bit different:
Certificate cert = keyStore.getCertificate(alias);
keyStore.setCertificateEntry(newAlias, cert);
keyStore.deleteEntry(alias);

How to get sub-root certificates in the certificate?

I'm reading the certificate file with the following methods :
File certFile = new File("E:/mycert.cer");
InputStream stream = new FileInputStream(certFile);
CertificateFactory factory = CertificateFactory.getInstance("X509");
X509Certificate certificate = (X509Certificate) factory.generateCertificate(stream);
how to get the root certificate of the certificate with java programming.?
How to get sub-root certificates in the certificate?
You can't. They aren't in the certificate. You need to:
Have a stream that contains a certificate chain, not just a single certificate, and
Call generateCertificates() instead of generateCertificate(), so as to get a Collection<? extends Certificate>, or
Call generateCertPath() so as to get a CertPath, which contains an ordered List of Certificate, from which you can get the root, the leaf, and the intermediates.

How to verify PEM format certificate in Java

I have PEM format file, How can verify the signature in Java, as I followed http://download.oracle.com/javase/tutorial/security/apisign/versig.html but found that Java doesnt support PEM
You can read a certificate in a PEM file using BouncyCastle's PEMReader. If the content is an X.509 certificate, you should get an instance of X509Certificate and verify it as you want from there.
EDIT: Here is what the code should look like (not tried):
// The key with which you want to verify the cert.
// This is probably a CA certificate's public key.
PublicKey publicKey = ...;
PEMReader reader = new PEMReader(new FileReader("/path/to/file.pem"));
Object pemObject = reader.readObject();
if (pemObject instanceof X509Certificate) {
X509Certificate cert = (X509Certificate)pemObject;
cert.checkValidity(); // to check it's valid in time
cert.verify(publicKey); // verify the sig. using the issuer's public key
}
(Of course, as with any I/O operations, you'll need to close the reader perhaps with try/finally.)
Note that checkValidity and verify don't return anything: instead, they throw exceptions if when they fail.

How can I establish trust in a X.509 certificate issued by an intermediary?

I have an XML document that is digitally signed. I use the XML Digital Signature API to verify the signature. But this document is a SAML 2.0 Assertion that will be used for single sign-on into our web application. As such I need to establish trust in the X.509 certificate used to sign the XML document.
The code I am using to try and establish this trust is:
String filename = System.getProperty("java.home") + "/lib/security/cacerts".replace('/', File.separatorChar);
FileInputStream is = new FileInputStream(filename);
KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
String password = "changeit";
keystore.load(is, password.toCharArray());
PKIXParameters params = new PKIXParameters(keystore);
params.setRevocationEnabled(false);
CertificateFactory certFactory = CertificateFactory.getInstance("X.509");
CertPath certPath = certFactory.generateCertPath(Arrays.asList(signatureCertificate));
CertPathValidator certPathValidator = CertPathValidator.getInstance(CertPathValidator.getDefaultType());
CertPathValidatorResult result = certPathValidator.validate(certPath, params);
PKIXCertPathValidatorResult pkixResult = (PKIXCertPathValidatorResult) result;
TrustAnchor ta = pkixResult.getTrustAnchor();
X509Certificate cert = ta.getTrustedCert();
When run the call to certPathValidator.validate() throws a CertPathValidatorException with the message Path does not chain with any of the trust anchors.
Examining the certificate, it says it has been issued by OU=www.verisign.com/CPS Incorp.by Ref. LIABILITY LTD.(c)97 VeriSign,OU=VeriSign International Server CA - Class 3,OU=VeriSign\, Inc.,O=VeriSign Trust Network.
This is not one of the trust anchors in the JDK's cacerts key store.
However, using IE to inspect a similar certificate's trust chain I see that www.verisign.com/CPS Incorp.'s was issued by VeriSign Class 3 Public Primary CA, which does appear to be one of the trust anchors in the JDK's cacerts key store.
My question: how can I get Java to validate this certificate?
Insert the public cert of the issuing CA into the cacert keystore.
edit: You can use keytool or one of the other tools out there. Article describes keytool use: keytool-Key and Certificate Management Tool
Exactly what xelco said - add the intermediate CA:
OU=www.verisign.com/CPS Incorp.by Ref. LIABILITY LTD.(c)97 VeriSign,OU=VeriSign International Server CA - Class 3,OU=VeriSign\, Inc.,O=VeriSign Trust Network
To the JDK's key store. You can use keytool to do it.
Reason: Generally when an XML message is signed, the signature includes only the signing cert. X509 Certificates are like singly linked lists. The End Entity points to its issuer. The issuer points to its issuer until you get to a self-signed Root CA, which points to itself. To verify a certificate according to PKIX, the validator needs to be able to build the whole CA chain from end entity to self signed root, so every part of the chain (except for the end entity) must be in your certificate store.
I've got better solution. I've found java service that can be run and do everything for us.
Java:
http://code.google.com/p/java-use-examples/source/browse/trunk/src/com/aw/ad/util/InstallCert.java

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