http://www.bouncycastle.org/java.html: The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 to JDK 1.8. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.openssl.jcajce;

import java.security.Provider;

import org.bouncycastle.jcajce.util.DefaultJcaJceHelper;
import org.bouncycastle.jcajce.util.JcaJceHelper;
import org.bouncycastle.jcajce.util.NamedJcaJceHelper;
import org.bouncycastle.jcajce.util.ProviderJcaJceHelper;
import org.bouncycastle.openssl.PEMDecryptor;
import org.bouncycastle.openssl.PEMDecryptorProvider;
import org.bouncycastle.openssl.PEMException;
import org.bouncycastle.openssl.PasswordException;

public class JcePEMDecryptorProviderBuilder
{
    private JcaJceHelper helper = new DefaultJcaJceHelper();

    public JcePEMDecryptorProviderBuilder setProvider(Provider provider)
    {
        this.helper = new ProviderJcaJceHelper(provider);

        return this;
    }

    public JcePEMDecryptorProviderBuilder setProvider(String providerName)
    {
        this.helper = new NamedJcaJceHelper(providerName);

        return this;
    }

    public PEMDecryptorProvider build(final char[] password)
    {
        return new PEMDecryptorProvider()
        {
            public PEMDecryptor get(final String dekAlgName)
            {
                return new PEMDecryptor()
                {
                    public byte[] decrypt(byte[] keyBytes, byte[] iv)
                        throws PEMException
                    {
                        if (password == null)
                        {
                            throw new PasswordException("Password is null, but a password is required");
                        }

                        return PEMUtilities.crypt(false, helper, keyBytes, password, dekAlgName, iv);
                    }
                };
            }
        };
    }
}