Cryptopedia
Cryptography
Cryptography, commonly used for information encryption, identification, and non-reputation, is an essential method for both communicators to exchange information based on a protocol in a secret manner. It is a technical science focusing on the encryption and decryption or the subject of discovering a way to recondition (use a different word) transfer the information. The blockchain is supported by underlying technologies such as cryptography, consensus algorithms, distributed storage, and peer-to-peer (P2P) networking, among which the cryptography is the most necessary one to dive in.
*Non-reputation: a situation where a message’s author can’t successfully deny the act of sending the message and the validity of the message content.
Terms
Secret key- classified into encrypted secret key and decrypted secret key.
Plaintext- the information that directly represents the original text without any encryption.
Ciphertext- the information that conceals the meaning of the original text after the encryption.
Encryption- a process of transferring the plaintext to the ciphertext.
Decryption- a process of transferring the ciphertext to the plaintext.
Cryptographic algorithm- the encryption method and decryption method of the crypto. With the development of cryptography, the encryption method is generally called an encryption algorithm and the decryption method is called a decryption algorithm.
Symmetric Cryptography
Symmetric cryptography is an encryption method based on the one-key crypto. In other words, it is called one-key encryption, a process of using the same key to encrypt and decrypt, which simplifies the procedures and which is widely used. For example, the process of registering a membership on a website actually adopts the one-key encryption. However, the online secret key can be leaked easily, so it is not recommended to be used for encrypting essential information.
Asymmetric Cryptography
Asymmetric cryptography consists of a public key and a private key. The private key is used for decryption, and the public key is used for encryption, which is different from the symmetric cryptography that utilizes the same key to encrypt and decrypt. Since the public key is open to the public, it is also called the public-key algorithm.
How is asymmetric cryptography applied to the blockchain? On the blockchain, the public-key algorithm is used for encryption, and the digital signature is for trading, both of which complements one another.
In the process of the public-key algorithm, the public key is used for encryption, and the private key is used for decryption, which ensures that the information can only be decoded by the real owner. In trading, the private key can be used to create a digital signature to complete the trade. For instance, according to the BTC white paper, each BTC sender creates a digital signature of a random sequence in accordance with the public key of the previous transaction and the next receiver. This digital signature is attached to the end of the digital currency, which will be sent to the next receiver. So, the security of the digital signature decides the security of the blockchain.
Hybrid Crypto
A hybrid crypto is the combination of symmetric encryption and asymmetric encryption. The symmetric encryption is featured with fast computing speeds but low security; the asymmetric encryption has slow computing speeds but its security is strong. Therefore, the integration of both allows for the dispatching of the secret key and encrypted communication.
Quantum Cryptography
Theoretically, on the blockchain, the foe (choose different word) of the encryption is the quantum computer that has the fastest computing speed compared to any other equipment (choose different word). However, it has not been popularized yet. Considering that a quantum computer can reaccelerate the calculation of the inverse hash function, the nodes of the blockchain will suffer from serious damage if the blockchain is attacked, which will significantly weaken the security of the network. Not long after the advent (choose different word) of the quantum computers, quantum cryptography based on the uncertainty principle and the no-cloning theorem arose. Since quantum computers are not able to decode the information encrypted by quantum cryptography, the information security on the blockchain can be guaranteed.
*Non-reputation: a situation where a message’s author can’t successfully deny the act of sending the message and the validity of the message content.
Terms
Secret key- classified into encrypted secret key and decrypted secret key.
Plaintext- the information that directly represents the original text without any encryption.
Ciphertext- the information that conceals the meaning of the original text after the encryption.
Encryption- a process of transferring the plaintext to the ciphertext.
Decryption- a process of transferring the ciphertext to the plaintext.
Cryptographic algorithm- the encryption method and decryption method of the crypto. With the development of cryptography, the encryption method is generally called an encryption algorithm and the decryption method is called a decryption algorithm.
Symmetric Cryptography
Symmetric cryptography is an encryption method based on the one-key crypto. In other words, it is called one-key encryption, a process of using the same key to encrypt and decrypt, which simplifies the procedures and which is widely used. For example, the process of registering a membership on a website actually adopts the one-key encryption. However, the online secret key can be leaked easily, so it is not recommended to be used for encrypting essential information.
Asymmetric Cryptography
Asymmetric cryptography consists of a public key and a private key. The private key is used for decryption, and the public key is used for encryption, which is different from the symmetric cryptography that utilizes the same key to encrypt and decrypt. Since the public key is open to the public, it is also called the public-key algorithm.
How is asymmetric cryptography applied to the blockchain? On the blockchain, the public-key algorithm is used for encryption, and the digital signature is for trading, both of which complements one another.
In the process of the public-key algorithm, the public key is used for encryption, and the private key is used for decryption, which ensures that the information can only be decoded by the real owner. In trading, the private key can be used to create a digital signature to complete the trade. For instance, according to the BTC white paper, each BTC sender creates a digital signature of a random sequence in accordance with the public key of the previous transaction and the next receiver. This digital signature is attached to the end of the digital currency, which will be sent to the next receiver. So, the security of the digital signature decides the security of the blockchain.
Hybrid Crypto
A hybrid crypto is the combination of symmetric encryption and asymmetric encryption. The symmetric encryption is featured with fast computing speeds but low security; the asymmetric encryption has slow computing speeds but its security is strong. Therefore, the integration of both allows for the dispatching of the secret key and encrypted communication.
Quantum Cryptography
Theoretically, on the blockchain, the foe (choose different word) of the encryption is the quantum computer that has the fastest computing speed compared to any other equipment (choose different word). However, it has not been popularized yet. Considering that a quantum computer can reaccelerate the calculation of the inverse hash function, the nodes of the blockchain will suffer from serious damage if the blockchain is attacked, which will significantly weaken the security of the network. Not long after the advent (choose different word) of the quantum computers, quantum cryptography based on the uncertainty principle and the no-cloning theorem arose. Since quantum computers are not able to decode the information encrypted by quantum cryptography, the information security on the blockchain can be guaranteed.
