Known transparent attacks, explained.

Known – understand the obvious attack

A known plaintext attack (KPA) occurs when an attacker uses both encrypted and unencrypted data to discover the encryption algorithm or key.

In this attack, the hacker can access both the encrypted data (ciphertext) and the original unencrypted version (plaintext). By comparing the two, the attacker tries to find the encryption method or key.

For example, if the word “blockchain” is encrypted as “eorfnfkdlq”, knowing this pair can help an attacker decipher other message components that use the same key. This shows how even a small amount of information can help break the encryption in some encryption methods.

This attack exploits weaknesses in encryption techniques, which allow attackers to identify patterns or relationships between plaintext and ciphertext. If not properly protected, known plaintext attacks can compromise the security of an encryption system.

Two common techniques for using plaintext and ciphertext are frequency analysis and pattern matching.

Repetition Analysis: Attackers use simple encryption methods where each letter or symbol is replaced by a unique letter. By comparing the frequency of letters or patterns in the plaintext and ciphertext, attackers can reveal the key or decipher the rest of the message. Pattern Matching: Bad actors look for repeating patterns. If the same plaintext results in the same ciphertext, you can identify trends in the ciphertext and use them to figure out the encryption algorithm and finally decipher the entire message.

How does a known open attack work?

The attacker can “reverse” the encryption method using this known pair. Even if they don't know the exact key or algorithm at first, just finding this one pair of plaintext and ciphertext will allow them to start cracking the encryption.

Therefore, the more pairs the attacker has, the easier it is to know the encryption method and the key, which makes it much easier to decipher other encrypted messages using the same method.

Let's continue with the previous “blockchain” and “eorfnfkdlq” pair example to understand how the attack works:

Actions in plain text

Collecting Known Pairs: Attackers collect pairs of plaintext and corresponding ciphertext. These can be obtained through intercepted communications, data breaches or other means. By analyzing the pattern: the attacker compares the letters in the text (“blockchain”) with the letters in the ciphertext (“eorfnfkdlq”). By studying how each letter in the plaintext changes to a different letter in the ciphertext, the attacker can figure out the pattern. For example, the letter “b” changes to “e”, “l” to “o” and so on. Guessing the secret: Based on the changes between the plaintext and the ciphertext, the attacker can make educated guesses about the encryption algorithm. . For example, if the letters are changed by a certain number of places, the attacker can discover that every letter in the “blockchain” has been changed by a certain number of places in the alphabet. For example, in Caesar's register, you can change each letter by three places, as shown in the image above. Cracking the encryption: Once the attacker figures out the pattern or encryption rule, they can use that knowledge to decrypt other components. A message or future messages that use the same key or algorithm.

Did you know this? Caesar's secret method was named after Julius Caesar, who used it for his private messages.

Selective obfuscation attacks (CPA) and known plaintext attacks (KPA)

Plaintext attacks involve adversaries selecting plaintext and analyzing the corresponding ciphertext, while known obfuscation attacks involve attackers having plaintext knowledge.

Simply put, the key difference between CPA and KPA is:

Plaintext Attacks: Attackers can pick or choose any plaintext and learn how to encrypt it into ciphertext. The charges themselves.

Understanding these differences is essential to developing strong cryptographic defenses.

Did you know this? Phishing is where attackers impersonate trusted sources to trick individuals with sensitive information such as passwords, while plaintext refers to messages that are not easily encrypted and can be read by anyone.

How to prevent an open attack if detected?

To protect against known obfuscation attacks, use strong encryption algorithms, securely manage encryption keys, use unique keys per session, and add randomness to encryption processes to improve protection against attacks.

Choose encryption algorithms that are resistant to known obfuscation attacks using strong encryption techniques. By preventing patterns in the plaintext from matching patterns in the ciphertext, modern cryptographic algorithms such as the Advanced Encryption Standard (AES) are made to survive such attacks. AES is a widely used symmetric encryption algorithm known for its security and efficiency.

Securely manage encryption keys to prevent unauthorized access. Use secure keystores, rotate your keys frequently, and use strong key generation techniques. Also, avoid encrypting unknown, predictable pieces of data. Encrypt the entire message or file to stop an attacker from using known pairs.

Also, use different keys for different sessions and efforts. Because each session uses a different encryption key, the impact of a known plaintext attack is reduced. Also, keep your systems, libraries, and encryption software up-to-date. Security patches that fix vulnerabilities are frequently included in updates.

Before encrypting the plaintext of the data, add a cryptographic salt – a random value – to it. This makes each encryption unique, even when encrypting the same plaintext multiple times. Also, avoid encryption methods that are known to be vulnerable to known open attacks. Exercise due care when choosing encryption algorithms.