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Cryptography

Cryptography is Study of secure communication techniques.

Cryptography plays a vital role in securing communication and data in the digital world. In the context of blockchain technology, it provides the foundation for secure transactions, digital signatures, and distributed consensus mechanisms

Cryptography In Blockchain​

Cryptography is an essential component of blockchain technology. It ensures the security and integrity of data stored on a blockchain. Here is some key aspects of cryptography in blockchain:

Hash Functions​

A hash function is a one-way function that takes an input and produces a fixed-size output, typically a bit string. In the context of blockchain, hash functions are used to create unique identifiers for blocks and transactions. The most commonly used hash function in blockchain is SHA-256, which produces a 256-bit output.

Digital Signatures​

Digital signatures play a crucial role in securing transactions on a blockchain. They are used to prove the authenticity and integrity of the data. In blockchain technology, digital signatures are created using public-key cryptography. A user signs a transaction with their private key, and anyone can verify the signature using the corresponding public key.

Consensus Mechanisms​

Cryptography is also at the heart of consensus mechanisms used in blockchain networks. These mechanisms ensure that only valid transactions are added to the blockchain and help maintain the security and integrity of the network. Some common consensus mechanisms include Proof of Work (PoW), Proof of Stake (PoS).

Simple Encryption & Decryption with Openssl​

echo HelloWorld > message.txt
openssl enc -aes-256-cbc -in message.txt -out message.bin
openssl enc -d -aes-256-cbc -in message.bin -out message.dec
cat message.dec
HelloWorld
# Using base64
openssl enc -base64 -in message.bin -out message.b64
openssl enc -d -base64 -in message.b64 -out message.ptx

Generate Key-Pairs with openssl - RSA​

openssl genpkey -algorithm RSA -out privatekey.pem -pkeyopt rsa_keygen_bits:1024
openssl rsa -pubout -in privatekey.pem -out publickey.pem

Encrypt and Decrypt using RSA Key-Pairs​

openssl rsautl -encrypt -inkey publickey.pem -pubin -in message.txt -out message.rsa
openssl rsautl -decrypt -inkey privatekey.pem -in message.rsa -out message.dec