Do you ever need to simply track the existence or lack thereof of something? Just a simple 1 or 0? Sure, we all do. Now, have you ever had to do this for millions of items? If so, what would you use? Many employ boolean arrays (just peruse database and data science projects on GitHub). […]
Digital signatures verify the authenticity of digital messages through the use of a cryptographic hash function and asymmetric encryption. It provides message integrity (via the hash function and encryption), authentication (via encryption), and non-repudiation (via asymmetric encryption).
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Hashed message authentication codes (HMAC) are a type of message authentication code employing a cryptographic hash function and secret key. It provides message integrity (via the hash function and encryption) and authentication (via encryption). It does not provide non-repudiation, as it uses a symmetric key which anyone can use to sign a message (no guarantee
A secure hash is a one-way cryptographic hash of a message whose producing algorithm should be intentionally slow. Why is the latter part important? It combats against brute-force and word list attacks. That is, it requires so much time to create a hash from an attempt, searching the entire password space becomes infeasible. To increase
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If you’ve been programming long enough, you’ve probably come across this oddity – operating on sorted arrays tends to be faster than unsorted. Why? The answer pertains to branch prediction. In this post, I will provide a brief overview of branch prediction as it pertains to programming (specifically Java). Examples are provided in terms of
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At times it is more convenient to use a simple embedded database then to setup and configure a DBMS. For instance, one can use an embedded DB to store parameters or test results for quick and easy analysis. In this post, I will provide a simple example of using Apache Derby/JavaDB (JavaDB is Oracle’s version
Sorting a single-element collection (e.g., arrays or lists) is quite easy in Java. It uses advanced techniques like CountingSort and DualPivotQuickSort. However, it is sometimes necessary to sort multi-element collects such as LinkedHashMaps. Prior to streams in Java 1.8, there was no relatively simply means of sorting these types of collections. I say “relatively simple”
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In Java, the java.util.Properties class allows access to persistent properties defined in a file. Those values are kept as key=value pairs. For sensitive data (such as passwords or access codes), these files provide direct access to the values by simply opening them. Therefore, it is sometimes necessary to encrypt those values. In this post, I
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This post will discuss AES 256 in Java. To achieve the desired key length of 256, the Java Cryptography Extension (JCE) must be installed. If you’d rather not worry about adding the files for the JCE, simply change keyLength in AESTest.java from 256 to 128 (the maximum limited strength key length).
Java is capable of unlimited strength cryptography, just not out of the box. As the README from the Java Cryptography Extension (JCE) states, “Due to import control restrictions of some countries, the version of the JCE policy files that are bundled in the Java Runtime Environment, or JRE(TM), 8 environment allow ‘strong’ but limited cryptography
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