http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.util.encoders;

import java.io.IOException;
import java.io.OutputStream;


Encode and decode byte arrays (typically from binary to 7-bit ASCII 
encodings).

/**
 * Encode and decode byte arrays (typically from binary to 7-bit ASCII 
 * encodings).
 */
public interface Encoder
{
    int encode(byte[] data, int off, int length, OutputStream out) throws IOException;
    
    int decode(byte[] data, int off, int length, OutputStream out) throws IOException;

    int decode(String data, OutputStream out) throws IOException;
}