Overview of data encryption and various algorithms and implementation examples

Data Encryption

Data encryption will be a technique for irreversibly transforming data and protecting it from unauthorized access and information leakage. Through encryption, data is transformed into a form that depends on a specific key and is unintelligible to those who do not know the key, so that only those with the legitimate key can decrypt the data and restore it to its original state.

The following describes the main elements and common methods of data encryption.

• Key: The secret information used in encryption and needed to protect and decrypt data. The key is a sequence of random bits that must be sufficiently long and unpredictable.
• Symmetric Key Cryptography: A cryptographic scheme in which the same key is used for both encryption and decryption. Encryption Standard (DES).
• Public Key Cryptography: A cryptographic scheme that uses a pair of keys (a public key and a private key), where the public key is publicly available and used for encryption and the private key is a secret key known only to the holder and used for decryption. RSA (Rivest-Shamir-Adleman) and Elliptic Curve Cryptography (ECC) are representative examples of public key cryptography. For more information on public key cryptography, see “Public Key Cryptography: Denfi-Hellman Key Exchange” and “Digital Signature RSA Cryptography.
• Hybrid Cryptography: A cryptographic method that combines symmetric key cryptography and public key cryptography, whereby symmetric key cryptography is used to encrypt data, the symmetric key itself is encrypted with a public key cryptography and transmitted, the receiver decrypts the symmetric key with a private key and decrypts the data using that key. The receiver decrypts the symmetric key with the private key and uses the symmetric key to decrypt the data.
• Block Cipher: A block cipher is a cipher that divides data into blocks of fixed length and encrypts each block. A typical block cipher is AES, which divides data into 128-bit blocks and encrypts them.
• Stream Cipher: A stream cipher processes data as a continuous stream and encrypts each stream. Since stream ciphers encrypt data bit by bit, they are suitable for encrypting long data.

Data encryption is widely used to meet security and privacy requirements, for example, encrypting online communications (HTTPS), encrypting databases, and protecting and securing data confidentiality.

About Data Encryption Algorithms

Various algorithms are used for data encryption. Typical algorithms are described below.

• AES (Advanced Encryption Standard): AES is a widely used symmetric-key encryption algorithm that uses 128-bit, 192-bit, or 256-bit key sizes to encrypt data in fixed-length blocks, AES is recognized as an encryption algorithm that balances security and efficiency.
• RSA (Rivest-Shamir-Adleman): RSA is the leading public-key cryptographic algorithm based on the difficulty of prime factorization, where the sender encrypts the data using the other party’s public key and the receiver decrypts it using the private key. RSA is also widely used for digital signatures and key exchange.
• ECC (Elliptic Curve Cryptography): ECC is a public-key cryptographic algorithm based on the difficulty of the discrete logarithm problem on an elliptic curve; ECC has the advantage over RSA of using shorter key sizes to provide comparable security, It is often used in resource-constrained environments and mobile devices.
• Blowfish: Blowfish is a symmetric key cryptographic algorithm characterized by its ability to use variable-length key sizes. However, it is somewhat less secure than more recent algorithms.

These are typical algorithms, but in reality there are many other encryption algorithms, and the choice of encryption should be made in consideration of security requirements, performance requirements, and ease of key management. New encryption algorithms are also being researched and developed.

Libraries and platforms used for data encryption

For data encryption, there are a variety of encryption libraries available for many programming languages and platforms. Some representative libraries and platforms are described below.

• OpenSSL: OpenSSL is an open source cryptographic library implemented in C. It provides a variety of encryption algorithms, including SSL/TLS implementations, symmetric key ciphers, public key ciphers, and hash functions, and can be used on many platforms.
• Bouncy Castle: Bouncy Castle is an open source cryptographic library for Java and C#. It provides a wide range of cryptographic functions, including symmetric key cryptography, public key cryptography, hash functions, and digital signatures.
• Cryptography.io: Cryptography.io is a cryptography library for Python that supports encryption algorithms such as AES, RSA, and ECC, and provides features such as secure key generation and signature verification.
• Libsodium: Libsodium is a cryptographic library for C and other programming languages featuring a concise API and high security.
• AWS Encryption SDK: The AWS Encryption SDK will be an encryption framework for Amazon Web Services (AWS). It can be used with a variety of programming languages to easily implement data encryption, decryption, and key management.

These libraries provide useful functions for implementing encryption algorithms, key management, and data encryption/decryption.

On an example implementation of data encryption using python

The following is an example implementation of data encryption using Python. In this example, the AES symmetric key cryptographic algorithm is used to encrypt text data.

from cryptography.fernet import Fernet

def generate_key():
    # generate a key
    key = Fernet.generate_key()
    return key

def encrypt_message(message, key):
    # Encrypt messages with a key
    cipher_suite = Fernet(key)
    encrypted_message = cipher_suite.encrypt(message.encode())
    return encrypted_message

def decrypt_message(encrypted_message, key):
    # Decrypt encrypted messages using a key
    cipher_suite = Fernet(key)
    decrypted_message = cipher_suite.decrypt(encrypted_message).decode()
    return decrypted_message

# Key Generation
key = generate_key()

# Message Encryption
message = "This is a secret message."
encrypted_message = encrypt_message(message, key)
print("暗号化されたメッセージ:", encrypted_message)

# Message Decryption
decrypted_message = decrypt_message(encrypted_message, key)
print("復号化されたメッセージ:", decrypted_message)

The above code uses the Fernet class of the cryptography library to perform encryption and decryption: the generate_key function generates a random key, the encrypt_message function encrypts the message, and the decrypt_message function decrypts the encrypted message. The encrypt_message function decrypts the encrypted message.

Data Encryption and Blockchain Technology

Data encryption and blockchain technology may be used in combination to improve security and data reliability. The following describes the relationship between data encryption and blockchain technology.

• Protecting Data Confidentiality: A blockchain is a distributed ledger in which data is shared among participants. However, not all data is publicly available; certain data must remain confidential, and data encryption is used to protect confidentiality. Encrypting data in this manner ensures that only authorized participants can decrypt the data.
• Data integrity protection: Blockchains will track transactions and data changes on a distributed network. To prevent data tampering or unauthorized changes, data integrity must be ensured, and data encryption can protect hash values and digital signatures of data. If the data in a block is tampered with, the hash value or signature will change, thus detecting unauthorized changes.
• Key management and decentralization: In blockchain, key management is important on a decentralized network. Keys need to be protected and shared in a secure manner, and smart contracts and cryptographic methods on the blockchain can be used to manage key generation, distribution, and sharing.
• Protecting privacy: Because the blockchain is a public ledger, there are concerns regarding the privacy of participants. Data encryption is used as one means of protecting participant privacy and, combined with features such as anonymity and security tokens, allows transactions and data to be processed on the blockchain while ensuring privacy.

Data encryption, when combined with blockchain technology, is an important means of protecting data confidentiality, integrity, and privacy.

Reference Information and Reference Books

Detailed information on cryptographic processes is also provided in “Encryption and Security Techniques and Data Compression Techniques. Please refer to that as well.

Reference book is “Tutorials on the Foundations of Cryptography: Dedicated to Oded Goldreich”

“Cryptography Made Simple“

“Practical Cryptography in Python: Learning Correct Cryptography by Example“

“Introduction to Modern Cryptography”