Added extra commits on private blockchain and added permissioned bloc…

…kchain (#552)

Cryptography/readme.md

@@ -103,6 +103,7 @@ Blockchain is a distributed database that maintains a continuously growing list
 ## Types of Blockchain are as follows:
 1. [Public Blockchain](#public-blockchain)
 2. [Private Blockchain](#private-blockchain)
+3. [Permissioned Blockchain](#permissioned-blockchain)
 
 ### [Public Blockchain](Blockchain/PublicBlockchain/readme.md)
 A public blockchain is a blockchain that is accessible to anyone. Public blockchains are open to anyone who wants to participate in the network. This means that anyone can view the blockchain and its transactions, and anyone can participate in the network by mining and validating transactions. Public blockchains are also known as permissionless blockchains.
@@ -124,4 +125,39 @@ Public blockchains also attract participants who may not be honest in their inte
 
 ### [Private Blockchain](Blockchain/PrivateBlockchain/readme.md)
 A private blockchain is a blockchain that is only accessible to a select group of people. Private blockchains are not open to the public. This means that only a select group of people can view the blockchain and its transactions, and only a select group of people can participate in the network by mining and validating transactions. Private blockchains are also known as permissioned blockchains.
+Private blockchains control who is allowed to participate in the network. If the network is capable of mining, its private nature could control which users can execute the consensus protocol that decides the mining rights and rewards. Additionally, only select users might maintain the shared ledger. The owner or operator has the right to override, edit, or delete the necessary entries on the blockchain as required or as they see fit.
+
+## Advantages
+A private blockchain is not decentralized. It is a distributed ledger that operates as a closed database secured with cryptographic concepts and the organization's needs. Only those with permission can run a full node, make transactions, or validate/authenticate the blockchain changes.
+
+By reducing the focus on protecting user identities and promoting transparency, private blockchains prioritize efficiency and immutability—the state of not being able to be changed.
+
+These are important features in supply, logistics, payroll, finances, accounting, and many other enterprise and business areas.
+
+## Disadvantages
+While purposefully designed for enterprise applications, private blockchains lose out on many of the valuable attributes of permissionless systems simply because they are not widely applicable. They are instead built to accomplish specific tasks and functions.
+
+In this respect, private blockchains are susceptible to data breaches and other security threats. This is because there is generally a limited number of validators used to reach a consensus about transactions and data if there is a consensus mechanism.
+
+In a private blockchain, there may not be consensus but only the immutability of entered data unless an operator or administrator can make changes.
+
+## [Permissioned Blockchain](Blockchain/PermissionedBlockchain/readme.md)
+Permissioned blockchains are a mix between the public and private blockchains and support many options for customization.
+
+## Advantages
+Permissioned blockchain advantages include allowing anyone to join the permissioned network after a suitable identity verification process. Some give special and designated permissions to perform only specific activities on a network. This allows participants to perform particular functions such as reading, accessing, or entering information on the blockchain.
+
+Permissioned blockchains allow for many functions, but one most interesting to businesses is Blockchain-as-a-Service (BaaS)—a blockchain designed to be scalable for the needs of many companies or tasks that the providers rent out to other businesses.
+
+Blockchain-as-a-Service reduces costs for many businesses that can benefit from using blockchain technology in their business processes.
+
+For example, say a business wants to improve transparency and accuracy in its accounting processes and financial reporting. It could rent blockchain accounting services from a BaaS provider. The blockchain would provide an interface where entries are made by end users and then automates the rest of the accounting processes.
+
+In this way, there are fewer errors and no way for other parties to alter financial data after it is entered. As a result, financial reports to management and executives become more accurate, and the blockchain is accessible for viewing and generating real-time financial reports.
+
+The business might choose to have its invoicing, payments, book-keeping, and tax reporting automated. Additionally, blockchain can prevent anyone with dishonest intentions from altering financial data or taking advantage of weaknesses in accounting processes.
+Disadvantages
+The disadvantages of permissioned blockchains mirror those of public and private blockchains, depending on how they are configured. One key disadvantage is that because permissioned blockchains require internet connections, they are vulnerable to hacking. By design, some might use immutability techniques such as cryptographic security measures and validation through consensus mechanisms.
+
+While most blockchains are thought to be unhackable, there are weaknesses. Cryptocurrency theft occurs when a network is hacked into, and private keys are stolen. Permissioned blockchains also suffer this weakness because the networks that connect the users to the service depend on security measures that can be bypassed. User information can be stolen and accounts hacked into, similar to enterprise-level data breaches like the one Target suffered in 2013 when a third-party with access to the network was hacked.