As known Java crypto provider require be a signed Jar file for using some algorithms types (Cipher for example) otherwise java.lang.SecurityException will be thrown (JCE cannot authenticate the provider).
Does Android require security provider be a signed jar?
I developed a simple provider with dummy cipher and as expected in JVM I received SecurityException but on Android my cipher works corrdectly.
Related
I am using a test app that used java for TLS communication. Standard Oracle java is installed in my system.
I need to use the TLS_DHE_RSA_WITH_AES_128_CCM cipher suite, which is not supported by standard Java, so many suggested using Bouncy Castle. I downloaded and copied the bcprov-ext-jdk18on-171.jar to $JAVA_HOME/lib folder.
Also, updated java.security file to include Bouncy Castle in the provider list as below:
security.provider.4=org.bouncycastle.jce.provider.BouncyCastleProvider
I still cannot get TLS_DHE_RSA_WITH_AES_128_CCM to work though.
Are the steps I did sufficient and correct? Can someone suggest the steps to install and configure Bouncy Castle?
The BouncyCastleProvider adds cryptographic algorithms such as the AES in the CCM mode of operation to the available algorithms of Cipher and other classes. As CCM is not included by default in Java, you will need to register this provider through code (i.e. Security.addProvider(new BouncyCastleProvider)) or adding it into the java.security file (as demonstrated in the question). You will probably want to add it to the end of the provider list as the algorithms of the Oracle provider are generally better tested and may be sped up using hardware acceleration.
However, the BouncyCastleProvider does not contain an implementation of the TLS protocol. You'd need to register the BouncyCastleJsseProvider for that instead. This is required as the Java TLS implementation won't magically know how to use the CCM implementation within Bouncy Castle. JSSE is an acronym of the Java Secure Socket Extension.
You can add that provider at the start of the providers so you know for sure that this provider is used for implementing TLS:
Security.insertProviderAt(new rg.bouncycastle.jsse.provider.BouncyCastleJsseProvider(), 1);
And you can also directly register it in the java.security file.
Note that the JSSE provider doesn't provide implementations such as RSA or AES for Cipher or Signature so it should not be in the way.
What's the padding mode for AES/GCM? I understood it can be NoPadding, as in ECB mode it can be PKCS5Padding, how about in GCM mode? in JCE interface, we need provide "algorithm/mode/padding" (Reference).
So I used the following code to get the instance and it works in JDK but failed in IBM SDK which says
cannot find provider for supporting AES/GCM/PKCS5Padding
Cipher.getInstance("AES/GCM/PKCS5Padding");
What's real use case for padding?
GCM is a streaming mode which means that the ciphertext is only as long as the plaintext (not including authentication tag). GCM doesn't require a padding. This means that the PKCS5Padding version is actually only a synonym for NoPadding for convenience during programming.
Some providers don't have this strange mode. Java has pluggable cryptographic providers and basically all JRE distributions have a default cryptographic provider which may have different cipher strings and defaults than those of other providers.
There are cases where padding the plaintext makes sense. For example, you can hide the length of the actual plaintext by appending a random length PKCS5Padding.
I'd like to use AES-GCM with BouncyCastle as the provider in order to avail myself of integrity checks using decryption. I'm curious about the kind of exception raised when the integrity check fails. Is it InvalidCipherTextException?
Also are there any other exceptions I should be handling in the context of decrypting an AES-GCM encrypted blob?
I see that there are a few more exceptions listed out at http://www.cs.berkeley.edu/~jonah/bc/org/bouncycastle/crypto/package-tree.html
For the lightweight API, the resulting exception is indeed the InvalidCipherTextException. This answer has been extracted from the Bouncy Castle source code, which is openly available (e.g. using anonymous access to the source repository).
if (!Arrays.constantTimeAreEqual(this.macBlock, msgMac))
{
throw new InvalidCipherTextException("mac check in GCM failed");
}
This seems identical in the 1.13 to 1.18 version of this file in the repository, please check again for later versions.
I have been able to run decryption and encryption locally using the bouncycastle jars. I have generated keys that I want to put the public key a client (Java and Android) and the private key in a web service. I have been able to encrypt and encoded a message and send the encrypted message to the webservice (on a hosted service by Lunarpages), but the webservice decryption fails with a FileNotFoundException on the line
BouncyCastleProvider bc = new BouncyCastleProvider();
or
Security.addProvider(new BouncyCastleProvider());
The bcprov-ext-jdk14-146.jar and the bcprov-jdk14-146.jar is included in the web-inf lib directory.
Is there something I can do programmatic to enable this or does Lunarpages have to do something?
I couldnt even get a stacktrace to print for me and so I thought I might attempt a different provider to see if I get a better response - the SunJCE.
access denied (java.security.SecurityPermission insertProvider.SunJCE)
java.security.AccessControlContext.checkPermission(AccessControlContext.java:269)
java.security.AccessController.checkPermission(AccessController.java:401)
java.lang.SecurityManager.checkPermission(SecurityManager.java:524)
java.lang.SecurityManager.checkSecurityAccess(SecurityManager.java:1673)
java.security.Security.check(Security.java:1307)
java.security.Security.insertProviderAt(Security.java:697)
java.security.Security.addProvider(Security.java:757)
net.wpstudios.tcws.pgp.RSAEncrypt.generateKeys(RSAEncrypt.java:81)
javax.servlet.http.HttpServlet.service(HttpServlet.java:165)
javax.servlet.http.HttpServlet.service(HttpServlet.java:103)
com.caucho.server.http.FilterChainServlet.doFilter(FilterChainServlet.java:96)
com.caucho.server.http.Invocation.service(Invocation.java:315)
com.caucho.server.http.CacheInvocation.service(CacheInvocation.java:135)
com.caucho.server.http.RunnerRequest.handleRequest(RunnerRequest.java:346)
com.caucho.server.http.RunnerRequest.handleConnection(RunnerRequest.java:274)
com.caucho.server.TcpConnection.run(TcpConnection.java:139)
java.lang.Thread.run(Thread.java:534)
Does the FileNotFound exception matter? Obviously the caucho server setup is using access restrictions on adding providers. Never mind that, if you want to develop some application level encryption/decryption you can simply use the bouncy castle crypto API directly. It's not as friendly as the JCE but it is useable enough. This might not work if you want to use a library that in its turn uses the JCA/JCE framework though.
Lunarpages is to change the permissions or add providers manually (using resin.conf, it seems), but it might be hard to change them just for you, unless you are the only one using the Java application server. It never hurts to ask I suppose.
Hi
I am trying to user RSA on J9. The algorithm is offered by the 'J9JCE' provider which is an installed extension(i listed all the existing providers and algorithms and found them) but the exception i get is:
Exception in thread "main" java.security.NoSuchAlgorithmException: JCE provider signer certificates not found/read
at javax.crypto.Cipher.getInstance(Cipher.java:191)
at Test.encript(Test.java:26)
at Test.main(Test.java:42)
I still don't know the answer to the problem but a workaround is to use the provider from Bouncy Castle which works fine.