Cryptography

Key Takeaways 

• Cryptography secures data from unauthorized access. In blockchain, it secures transactions between nodes. Blockchain revolves around cryptography and hashing. 
• Cryptography encrypts messages in the network. Hashing secures block data and connects blocks. 

What is Cryptography? 

Cryptography keeps information safe during communication. It’s from Greek words meaning “hidden” and “to write.” Here are some terms: 

• Encryption: Changes regular text into random bits. 
• Key: Information needed for the cryptographic algorithm. 
• Decryption: The opposite of encryption, turning random bits back into text. 
• Cipher: A math function that changes text into random bits. 

Types of Cryptography 

There are two main types of cryptography: 

1. Symmetric-key Cryptography 
2. Asymmetric-key Cryptography 
3. Symmetric Key Encryption 

This type uses the same key for both encryption and decryption. It’s handy for securing websites and data. The only hitch is sharing the key safely. Popular systems include DES and AES. 

Features of Symmetric-key Cryptography: 

• Uses one secret key for both parties
• Great for encrypting lots of data quickly
• Needs less power and is faster
• Asymmetric Key Encryption

This method uses different keys for encryption and decryption. It uses public and private keys. Public keys let strangers share info like email addresses. On the other hand, private keys decrypt messages and verify signatures. 

Features of Asymmetric-key Cryptography:

• Uses different keys for encryption and decryption. 
• Slower than symmetric encryption. 
• Important for verifying web servers. 

Hash Functions 

Hash functions don’t need keys. They use a cipher to create a fixed-length hash value from the text. It’s hard to go back to the original text from the hash value. So, the hash function acts like an ID for any content. It turns any size text into a unique, fixed-length code. 

Hashing might seem like encryption, but they’re different. Hashing doesn’t need to undo the code like encryption does. It turns text into code using mathematical equations. The code it makes is called a hash digest, hash value, or hash code. It’s like a fingerprint for the content. 

Good hash algorithms have certain traits: they’re consistent, hard to guess, don’t repeat, work fast, and have a snowball effect. 

How Cryptography Keeps Blockchain Safe?

A toolbox full of security tools, that’s cryptography for blockchain! Here’s what it helps with: 

• Identifying Changes: Cryptography creates unique fingerprints (hashes) for data. Suppose someone tampers with the data, the fingerprint changes, raising the alarm! 
• Keeping Secrets Safe: Sensitive information can be scrambled with a key (encryption), so only authorized people can see it. 
• Verifying Identities: Digital signatures are like electronic receipts. They prove who sent a message and that it wasn’t tampered with. 
• Protecting Keys: Cryptography secures the tools (keys) used for encryption and signing, keeping them out of the wrong hands. 

Cryptography’s Toolbox for Blockchain 

• Hash Functions: An algorithm that turns any data into a short, unique code. That’s a hash function! It’s great for checking if data has been changed. 
• Digital Signatures: Digital signatures prove a message is real and hasn’t been tampered with. 
• Encryption: This hides data with a key, making it unreadable unless you have the other key to unlock it. 
• Merkle Trees: A record system that lets you check if a single file is correct without looking at everything. Merkle Trees do that for blockchain data! 

Benefits of Cryptography in Blockchain 

1. Reliability: Cryptographic hashing ensures transactions are irreversible and secure, making data stored on the blockchain trustworthy and protected from attacks. 
2. Security: Cryptography is vital for blockchain security. Each transaction is encrypted, and users can access their data using private or public keys. Cryptographic hashing prevents tampering with data, enhancing security. 
3. Scalability: The cryptographic hash function enables secure recording of countless transactions on the blockchain. Combining multiple transactions into one hash allows for scalability. This makes blockchain networks more efficient. 

To Sum up 

Cryptography is crucial for how blockchain works. It uses public key encryption for wallets and transactions. Hashing makes sure data can’t be changed, and Merkle trees help organize transactions. Cryptography and blockchain go hand in hand. Digital signatures keep blockchain communication secure, but hash functions have even more potential.