Cryptography Techniques: Everything You Need to Know

Historically, ciphers were often used directly for encryption or decryption without additional procedures such as authentication or integrity checks. Single-key or symmetric-key encryption algorithms create a fixed length of bits known as a block cipher with a secret key that the creator/sender uses to encipher data (encryption) and the receiver uses to decipher it. One example of symmetric-key cryptography is the Advanced Encryption Standard (AES). AES is a specification established in November 2001 by the National Institute of Standards and Technology (NIST) as a Federal Information Processing Standard (FIPS 197) to protect sensitive information.

While it is widely believed by the computer science community, it has not been formally proven. Hence, while we can build cryptographic systems assuming this disparity, there is always a lingering risk of these systems becoming vulnerable if our assumption is proven incorrect in the future. Another potential solution is cryptography quantum, whereby it is impossible to copy data encoded in a quantum state. Storing keys alongside the information they have been created to protect increases their chances of being compromised. For example, keys stored on a database or server that gets breached could also be compromised when the data is exfiltrated.

Insider threats (user authentication, dual control, segregation of roles)

MD2, MD4, and MD5 These methods use a message digest (the hash value) that is 128 bits in length. When a message is encrypted with a user’s private key, the hash value that is created becomes the signature for that message. Each signature is unique, and any attempt to move the signature from one message to another would result in a hash value that would not match the original; thus, the signature would be invalidated. Extensive open academic research into cryptography is relatively recent, beginning in the mid-1970s.

She then encrypts the message with Bob’s key prior to sending the ciphertext to Bob. Only Bob can decrypt the ciphertext using his private decryption key, which remains secret. With symmetric encryption, we had the challenge of establishing a secure channel to share the secret encryption/decryption key prior to the encryption process.

🔗 Asymmetric key cryptography

Although hashing is considered a powerful technique to protect passwords and sensitive data, it is often incapable of a foolproof solution to comprehensive security control. An increasing pattern of attacks suggests that it’s not unusual for attackers to break into password databases and access pre-calculated hashes created for each password. Plain encryption offers only the confidentiality of the data, whereas authenticated encryption enforces authenticity and confidentiality. Authenticated encryption uses the GCM (Galois Counter Mode) and CCM (Counter Mode with CBC MAC) block cipher modes to enforce data authenticity and privacy. Simultaneous data authenticity and confidentiality enforcement offers protection from attack vectors, leaving minimal room for error when handling data in transit.

  • A block cipher is an encryption cipher characterized by two elements, namely its block size and its key size.
  • Cryptocurrencies use cryptographic technology to enable anonymous, secure, and trustless transactions.
  • Because the output of hash functions can’t be easily guessed, the network can trust that an actor in the network has expended a good deal of energy computing the result of a calculation.
  • In the decryption process, the receiver first computes the MAC on the ciphertext to verify that the tag is identical to the one received, then he decrypts the ciphertext once authenticity has been verified.
  • Symmetric key sharing presents great challenges, notably when it comes to sending the key between parties trying to exchange data in a secure manner over an insecure communication channel such as the Internet.

Therefore, encryptor in KP-ABE has no control over the users who can access the data, rather it needs to trust the key issuer in this regard. Homomorphic encryption (HE), as a method of performing calculations on encrypted information, has received increasing attention in recent years. The key function of it is to protect sensitive information from being exposed when performing computations on encrypted data.

Cryptography on the macro scale

ECC is used in several cryptographic protocols, including variants of Diffie-Hellman and ElGamal, which we will discuss in detail. Interestingly, this operation does not correspond to conventional addition but involves drawing a line through two points and determining where it intersects the curve a third time. The result of the addition is the reflection of this third point across the x-axis. Similarly, the Diffie-Hellman and ElGamal algorithms rely on the Discrete Logarithm Problem’s computational difficulty, also an NP problem. If a fast solution to this problem was found, these cryptographic systems would be compromised. Recording key management processes manually on paper or spreadsheets runs the risk of human error and makes the keys highly vulnerable to attack or theft.

What problems does cryptography solve

The security of the cryptosystem is said to be reduced to solving the hard problem and can be proven using cryptographic reduction. A widely deployed example is the RSA cryptosystem, whose security is based on the hardness of the factoring problem. There are several types of encryption algorithms; these include block ciphers and stream ciphers.

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