Discover how AES (Advanced Encryption Standard) enhances security within the blockchain ecosystem, particularly for data at rest and in transit. Learn about Advantages And Disadvantages Of AES.
The symmetric-key encryption method known as Advanced Encryption Standard (AES) is extensively used and respected around the world. Although it is fundamental to contemporary cryptography, its precise function within the blockchain ecosystem is sometimes misinterpreted.
What is Advanced Encryption Standard AES Blockchain?
AES is a symmetric-key block cypher that processes data in fixed 128-bit blocks and use the same key for both encryption and decryption. Because public transactions are viewable, the entire blockchain is not encrypted, but AES is essential for protecting critical parts of the blockchain. Using protocols like TLS/SSL to secure communication channels within blockchain networks and encrypting wallet data and private keys are two examples of this. Client-side encryption in blockchain-integrated decentralized file storage systems is also essential.
Characteristics and Features of AES
Key Sizes: The key sizes that AES offers are 128, 192, or 256 bits. Considered to be incredibly strong, AES-256 employs a 256-bit key and is used in numerous high-security applications, including the U.S. government for secret data.
Standardization: In 2001, the Data Encryption Standard (DES) was superseded by AES, which was made a standard by the U.S. National Institute of Standards and Technology (NIST). FIPS 197, the Federal Information Processing Standard, released it.
Efficiency and Security: AES is renowned for its effectiveness, speed, and robust security when used properly. According to reports, it is six times quicker than Triple DES.
Operations (Substitution-Permutation Network): Based on the substitution-permutation network idea, AES is an iterative cypher. Instead of using individual bits, it manipulates bytes of data. The input data is replaced and shuffled by a sequence of interconnected operations during the encryption process.
Rounds: The key length determines the number of rounds:
- 10 rounds for 128-bit keys.
- 12 rounds for 192-bit keys.
- 14 rounds for 256-bit keys.
How AES Works
AES treats each 128-bit block as a 16-byte (4×4) grid while processing data.
Key Expansion:
From the initial key, a Key Schedule algorithm determines each round key. By doing this, a different key is used in every round.
Encryption Process:
- Initial AddRoundKey: The first round key is XORed with the block of plaintext.
- Rounds of Transformation: Every round (except from the last one) follows these four basic steps:
- SubBytes: A predetermined lookup table known as an S-box is used to replace each byte in the 16-byte data block. This stage causes misunderstandings and creates a non-linear connection between the plaintext and the ciphertext.
- ShiftRows: The 4×4 matrix has varying amounts of leftward shift for each row. The first row remains unchanged, but the second, third, and fourth rows are shifted once, twice, and three times, respectively. Diffusion is thus given.
- MixColumns: Every four-byte column undergoes a mathematical transformation. By doing this, the effect of each byte is dispersed throughout the data in the column. The last round of encryption skips this step.
- AddRoundKey: The current 128-bit round key is XORed with the 16-byte matrix.
- Final Round: In the last round, the ciphertext is generated using SubBytes, ShiftRows, and AddRoundKey instead of the MixColumns step.
Decryption Process:
AddRoundKey, Inverse MixColumns, Inverse ShiftRows, and Inverse SubBytes are the inverse operations that are applied in reverse order during decryption, which reverses the encryption process. Symmetry is ensured by the decryption procedure being as effective as encryption.
Modes of Operation:
- To encrypt data bigger than a single block, AES has to be used in conjunction with another mode of operation because it only works with fixed 128-bit blocks. Common modes consist of:
- ECB (Electronic Codebook): Typically unsafe as it encrypts each block separately while allowing plaintext patterns to be seen in the ciphertext.
- CBC (Cipher Block Chaining): An Initialization Vector (IV) is needed for the initial block of plaintext as each block is XORed with the block of ciphertext that came before it before encryption.
- GCM (Galois/Counter Mode): Used in secure protocols such as TLS, it offers message authentication and encryption for further protection.
- CTR (Counter Mode): AES is transformed into a stream cypher by the encryption of a counter value.
Applications of AES
Despite not being the main cryptographic fundamental for the Ethereum or Bitcoin blockchain consensus process, AES’s prowess at symmetric encryption makes it indispensable for protecting critical network components.
AES is utilized or pertinent in the blockchain environment in the following ways:
Securing Wallets and Private Keys: The wallet file or private keys kept on a user’s device are encrypted using AES by a large number of cryptocurrency wallets, including both software and hardware wallets. To encrypt sensitive data, for instance, an AES key may be derived from a software wallet password. In order to encrypt connection with a computer and shield private keys and transaction data from physical threats, hardware wallets employ AES internally. Backups of private keys or wallet seed phrases are also frequently encrypted using the AES technique.
Encrypted Communication within Blockchain Networks: Communication between blockchain nodes or between a decentralized application (dApp) and a blockchain node/API frequently depends on secure protocols like TLS/SSL, even if blockchain data itself is publicly hashed and not AES encrypted. To protect these communication routes, TLS/SSL uses encryption suites, of which AES is a fundamental part.
Enterprise/Permissioned Blockchains: Certain sensitive information may be encrypted off-chain or within encrypted data fields that are then hashed on-chain using AES in private or consortium (permissioned) blockchains when participant data privacy is an issue. This method makes use of the blockchain’s integrity and immutability while preserving secrecy for critical transactions.
Zero-Knowledge Proofs (ZKPs) and Privacy Solutions (Indirectly): Cryptographic primitives that have been benchmarked or created alongside AES-like operations may be employed internally by some sophisticated privacy-focused blockchain solutions or layer-2 protocols that leverage ZKPs for efficiency. But usually, the straight ZKP method is not AES itself.
Decentralized File Storage Solutions: Before uploading their files to decentralized storage networks that connect with blockchains (like Filecoin or Storj), users often encrypt their data. The preferred client-side encryption technique is AES, which makes sure that only the user with the right key can access their data.
Why AES is NOT a Primary Blockchain Component (Limitations in Core Blockchain)
The public transactions on the blockchain are not encrypted using AES. The underlying ideas of the majority of public blockchains are to blame:
Public and Transparent Nature: Most public blockchains, including Ethereum and Bitcoin, operate on the fundamental tenet that transaction data must be transparent and unchangeable. Since only those with the key could verify transactions, this goal would be defeated if every transaction were encrypted using a symmetric key.
Hashing vs. Encryption: For data integrity and block chaining, blockchains mainly use cryptographic hash functions (such as SHA-256) and asymmetric cryptography (such as ECDSA for Bitcoin) for digital signatures, which prove ownership without disclosing keys. Unlike digital signatures and hashes, which are used to prove authenticity and integrity, AES is intended for secrecy, or keeping data hidden.
Key Management: If all transactions were AES encrypted, decentralization would be severely weakened as it would be unable to manage and distribute the symmetric keys to all participants for verification.
Advantages And Disadvantages Of AES
Advantages of AES
Because of its many benefits, AES is extensively used in many different applications, including those in the blockchain ecosystem:
High Security: AES provides more robust security by using several encryption rounds, which makes it more difficult to crack and impervious to brute-force attacks. It continues to be one of the most secure encryption algorithms known and has resisted intensive cryptanalysis.
Efficiency and Speed: Because AES is so much quicker than more antiquated algorithms like DES and Triple DES, it is perfect for applications that need high throughput or low latency.
Cost-Effectiveness: Due to its open-source nature and widespread availability, AES is an affordable method to adopt and use.
Implementation Flexibility: It is an easy-to-understand algorithm that can be implemented in both software and hardware.
Versatility and Global Standard: File/disk encryption, password management, secure communications (HTTPS, VPNs, Wi-Fi), and other applications use AES, which is extensively used and trusted worldwide for both government and private use.
Disadvantages of AES
AES’s efficacy depends on appropriate implementation and robust key management, despite its high level of security. Most threats originate from outside sources rather than flaws in the algorithm itself.
Weak Key Management: The data can be decrypted by hackers if encryption keys are not produced, kept, or transmitted securely.
Side-Channel Attacks: Attackers may use information that was disclosed during the encryption or decryption process (such as time or power use) to determine the encryption key. Constant-time algorithms and hardware safeguards are used in mitigation.
Brute-Force Attacks: Even while AES is quite resilient, utilizing shorter keys (such as AES-128 rather than AES-256) may theoretically make it more susceptible to upcoming developments in computing, such as quantum computing through Grover’s Algorithm. To enhance resistance, AES-256 is advised for critical applications.
Implementation Errors: Implementation errors, including improperly using encryption modes (like ECB mode, which reveals data patterns) or improperly padding data, can result in vulnerabilities. It is recommended to utilize secure modes such as GCM or CBC with appropriate Initialization Vectors (IVs).
Replay Attacks: Encrypted data may be intercepted and replayed if AES is used without an authenticated encryption mode (such as AES-GCM) or Message Authentication Codes (MACs).
Data at Rest vs. Data in Use: AES protects data when it’s in transit and at rest, but it can be attacked by memory dumps and other methods when it is being processed in memory.
Key Reuse: Using the same encryption key and IV again raises the risk of compromise when doing so across different data sets or sessions.
Insufficient Randomness: Because AES depends on randomness for both IVs and key creation, predictable encryption outcomes may arise from poor random number generators.
Human Errors: AES security can be jeopardized by incorrect setup, unsafe password usage, or exchanging encryption keys.
In conclusion, AES is essential for protecting the apps and auxiliary parts that communicate with the blockchain, ensuring the secrecy of sensitive information and communications within the larger ecosystem, but it does not encrypt the core of public blockchains. It is the recommended option for these particular use scenarios because to its efficiency and security.