Writing up a quick cheat sheet for cryptography terms and concepts.


A list of (almost) all the terms i have come across when learning about a drop of the vast ocean that is the AWS world. May come handy to revise / refresh memory when prepping for the associate-level certifications… or otherwise.


AWS DVA-C01 2020 — fear of the unknown. That’s how I relate to it. A beast, if not a devil. After more than a year of on-and-off preparation, and 2 months of rigorous continuous preparation, 3 days before my scheduled exam. May be I will have a different opinion AFTER the exam.

There are so many speculations and confusions.

What’s the syllabus? What to cover?

My answer : There is no definite syllabus, and that's the whole point.

Which course to depend on? Which practice test? Or rather, How many ? aCloudGuru? Stephane Maarek? Jon Bonso?

My answer : There…


Cryptography, or cryptology is all about communication between two parties in a secure manner, so that no third party can figure out what has been communicated.

The most conventional way to achieve cryptography is encryption-decryption. ie to encrypt the message in some way before sending across to the receiver. And the receiver decrypts the message (should know how to) and consumes it. The “should know how to” is the part which makes the communication secure. No third party “should know how to” decrypt the message.

In the IT world, there are various algorithms which define the “how to”. They work…


Originally developed by Facebook, Cassandra is now an open source, distributed, noSQL database designed to scale for large amounts of data. This article will explain how time-to-live (TTL) works in Cassandra.

TTL is a property attached to a column in Cassandra, though it can be defined at multiple levels in Cassandra. Its always defined in seconds.

The default TTL is applied on the whole table.

The TTL defined in the insert query, is applied to the…


OpenAPI is a global standard for describing REST APIs. The descriptions are made either in yaml or json format. These description files are immensely useful and have a lot of tools written around them. As they follow a defined standard, it’s easy to work with them. They provide the consumer of the API, a power to explore the API even before writing code to consume it.

But in real-life production scenarios, sometimes there is a requirement to customise the specification files. For example, a use case can be :

Some operations / fields should be visible only to some consumers…


Swagger and OpenAPI are very popular terms now a days. People building a new API want to use them. People working with legacy APIs want to use them too. Below i will be talking about some of the problems i faced when working with them.

As it is with a lot of other such standards, developing fresh using them is easier than migrating a legacy work. I recently worked on the later. ie exposing OpenAPI specs for a legacy API , which has 50+ versions supported in live production. …

Shivani Agrawal

A conscious soul. A keen learner. A book lover. An excited child.

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