**3a. What is a Cryptocurrency? b. Meaning of Cryptography, and how it make cryptocurrencies secure? c. Exploring the Steem Genesis Block and Signing in as proof of completion.** ![image.png](https://cdn.steemitimages.com/DQmPtKLRUizHyw8MANwZkzebPR4VYL2nvZ2qJiFZfH5wV8s/image.png)

#### MEANING OF CRYPTOCURRENCY

Cryptocurrency, additionally called crypto, is a sort of on-line means of payment that may be exchanged on-line to buy items and services. It is just like real-global currency, however it does not have any bodily appearance. It is transparent, encrypted and decentralized virtual money, that is based on blockchain technology and is also secured by cryptography. The main attributes of a cryptocurrency is its decentralization in nature. Decentralized in the sense that it is not provided by any authorities, it belongs to the user and cannot be controlled by the bank or the government. ![Cryptocurrency-3-600x333.jpg](https://cdn.steemitimages.com/DQmPpSbzmigGSW76jnmSXaCQXXd8XEWRB6haPCvMxxNHpga/Cryptocurrency-3-600x333.jpg) [source](https://www.analyticsinsight.net/best-cryptocurrency-to-buy-in-august-2021-for-big-profit/) Some features of cryptocurrency are: - It has a limit on the number of units that can exist, so bitcoin has 21 million limits. - It performs easy verification of funds transfer using hash algorithms that verify every transaction. - It does not have to rely on any authority or the real world bank. Cryptocurrency | Symbol -|- Bitcoin| BTC Etheruem|ETH Ripple|XRP Bitcoin cash|BCH Litecoin|LTC

#### MEANING OF CRYPTOGRAPHY AND HOW IT MAKES CRYPTOCURRENCY SECURE

Cryptography which also means encryption and decryption has been used over the centuries as a way to transfer information intended only for certain people. Today, encryption plays a vital role in cybersecurity to keep data out of the reach of cyber criminals around the world. So to define cryptography we can say is the means of turning information into a secure form, so that unauthorized people cannot access it. Cryptography protects information from cyber criminals with these basic functions: - Confidentiality: When private information is transmitted over the network or stored on a file server, its content can be encrypted, allowing only authorized persons who have the key to see it. - Integrity: Since ciphertext requires the use of a key to open data before it can be edited, encryption can ensure its integrity. - Non-repudiation: non-repudiation is the means to show that a user has performed an action. Non-repudiation stops someone from fraudulently “denying” an action. - Availability: The sender's authenticity can be verified by cryptography.

#### How it makes cryptocurrency secure

**Secret key cryptography** It uses one key to decrypt and encrypt. Here the sender makes use of the key to encrypt the plaintext and send the ciphertext to the receiver. The receiver puts in the same key to decrypt the message and retrieve the plaintext. Since it's only one key that is used for both functions, secret key cryptography can also be known as symmetric encryption. **Asymmetric key cryptography** Asymmetric key cryptography, additionally called public key cryptography, makes use of public and personal keys for encryption and decryption of data. The keys are certainly big numbers which have been paired collectively however aren't identical (asymmetric).

#### EXPLORING THE STEEM GENESIS BLOCK AND SIGNING IN AS PROOF OF COMPLETION.

To discover the Steem genesis block go to https://steemworld.org • Click on block explorer as proven below ![image.png](https://cdn.steemitimages.com/DQmP3DrPNx4B5Gx9FwmzNSU14aWqbnmoZzhaoB4yk8o2V1L/image.png) • Click ok for block 1 as proven below ![image.png](https://cdn.steemitimages.com/DQmPqj1dMdFS313Sm76CW9WRfnYNoaA2fk1WP1B1NrQnFSe/image.png) • Here are the info about the genesis block ![image.png](https://cdn.steemitimages.com/DQmbFpshHNjDEyUHoyFJqWrqsmHvhkYS5rQ1rDsJwVsDy5d/image.png) • Now one can sign in as indicated below ![image.png](https://cdn.steemitimages.com/DQmVyP6muiYVRmj8dohRgrLijVChdYBKUe3ZHS2YjxJ11cm/image.png) • Username/ password ![image.png](https://cdn.steemitimages.com/DQmfLXsmypWKYeHnCXYMSiQ5hVfGQyU8qvcgQGBRbZwzEcb/image.png) ![image.png](https://cdn.steemitimages.com/DQmb9APceJdFaT9ECm7398yCKSwyMm76zTRKQRoGwsaVyAh/image.png)

Cc: Professor @awesononso