Error parsing PKCS private key for Box Developer Edition - Gradle

Hi everyone,

I'm trying to Authenticate with my application using JWT with SDK, I have followed the tutorial, generated a public/private key pair using the Box platform, and stored the Json config file in my project.

Following the tutorial I first tried with the code example AccessAsAppUser.java and didn't found any issue.

But when I tried to replicate that example on my project, I'm getting the following exception:

Exception in thread "main" com.box.sdk.BoxAPIException: Error parsing PKCS private key for Box Developer Edition.
        at com.box.sdk.BoxDeveloperEditionAPIConnection.decryptPrivateKey(BoxDeveloperEditionAPIConnection.java:515)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.constructJWTAssertion(BoxDeveloperEditionAPIConnection.java:450)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.constructJWTAssertion(BoxDeveloperEditionAPIConnection.java:431)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.authenticate(BoxDeveloperEditionAPIConnection.java:320)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.tryRestoreUsingAccessTokenCache(BoxDeveloperEditionAPIConnection.java:419)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.getAppEnterpriseConnection(BoxDeveloperEditionAPIConnection.java:199)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.getAppEnterpriseConnection(BoxDeveloperEditionAPIConnection.java:226)
        at com.cisco.s3.api.box.BoxBaseClient.(BoxBaseClient.java:39)
        at com.cisco.s3.api.box.BoxBaseClient.main(BoxBaseClient.java:56)
Caused by: org.bouncycastle.pkcs.PKCSException: unable to read encrypted data: 1.2.***number removed for privacy***.1.5.13 not available: JCE cannot authenticate the provider BC
        at org.bouncycastle.pkcs.PKCS8EncryptedPrivateKeyInfo.decryptPrivateKeyInfo(Unknown Source)
        at com.box.sdk.BoxDeveloperEditionAPIConnection.decryptPrivateKey(BoxDeveloperEditionAPIConnection.java:504)
        ... 8 more
Caused by: org.bouncycastle.operator.OperatorCreationException: 1.2.***number removed for privacy***.1.5.13 not available: JCE cannot authenticate the provider BC
        at org.bouncycastle.openssl.jcajce.JceOpenSSLPKCS8DecryptorProviderBuilder$1.get(Unknown Source)
        ... 10 more
Caused by: java.security.NoSuchProviderException: JCE cannot authenticate the provider BC
        at javax.crypto.JceSecurity.getInstance(JceSecurity.java:105)
        at javax.crypto.SecretKeyFactory.getInstance(SecretKeyFactory.java:204)
        at org.bouncycastle.jcajce.util.NamedJcaJceHelper.createSecretKeyFactory(Unknown Source)
        at org.bouncycastle.openssl.jcajce.PEMUtilities.generateSecretKeyForPKCS5Scheme2(Unknown Source)
        ... 11 more
Caused by: java.util.jar.JarException: file:/[FILE].jar has unsigned entries - com/box/sdk/example/Main.class
        at javax.crypto.JarVerifier.verifySingleJar(JarVerifier.java:502)
        at javax.crypto.JarVerifier.verifyJars(JarVerifier.java:363)
        at javax.crypto.JarVerifier.verify(JarVerifier.java:289)
        at javax.crypto.JceSecurity.verifyProviderJar(JceSecurity.java:164)
        at javax.crypto.JceSecurity.getVerificationResult(JceSecurity.java:190)
        at javax.crypto.JceSecurity.getInstance(JceSecurity.java:102)
        ... 14 more

Is this a bug? I have installed the JCE in the java 1.8 folder, but I'm still getting that exception.

More information:

I'm using the Java SDK and adding it to my project with the Maven dependency:

compile 'com.box:box-java-sdk:2.23.2'

java version "1.8.0_171"
Java(TM) SE Runtime Environment (build 1.8.0_171-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.171-b11, mixed mode)