Cryptography is the science of passing information securely in the presence of third party adversaries. In simple language, it can be referred to as coding of the plaintext into a text that is commonly termed as ciphertext that cannot be deciphered by an unauthorized third party. Modern Cryptography amalgamates the concepts of Mathematics, Computer Science, and Engineering. The concept of cryptography has found its relevance in the digital world with various types of SSL certificates since the time the internet became a reliable and viable resource for information exchange and processing for organizations, banking, e-commerce, defense etc.
The building blocks of Cryptography are,
- Encryption
The process of coding the information in a language that is only accessed and decoded by authorized parties is known as encryption. Generally, encryption is done through some mathematical algorithm where a random key is generated and shared by the receiver and the message sender. There may be certain loopholes in the encryption schemes but a good encryption involves computational resources, skills, and proper knowledge to decode the message.
- Decryption
The decoding of the encrypted text by the intended authorized recipient is called as decryption. The decryption takes place by the key that is devised by the encryption algorithm.
Types of Keys that are used for Cryptography encryption and decryption,
- Symmetric key
In this type of encryption, the receiver and sender have the same type of key or you could say, the algorithm for encrypting and decrypting is same.
- Public key cryptography
Public cryptography is a tool where the encryption and decryption algorithms are different. The key used for encrypting the message is different from the one that will be used for decrypting the message, unlike the symmetric key cryptography. The message can be encrypted by anybody having receiver’s public key but the decryption can be done only by the sender’s private key. It is mostly used to secure electronic communication that happens over the Internet that is more susceptible to various kinds of third-party attacks.
Public key cryptography ensures the authenticity of the sender integrity of the message and prevents any type of modification in the transit.
- Digital signatures
The message is signed with the sender’s private key and verified with anyone who has the sender’s public key. This is one of the methods that ensure the authenticity and confidentiality of the sender and the shared information respectively.
CryptanalysisHow secure is the cryptographic encryption scheme implemented for security? In modern times, the common questions are - which type of SSL certificate to choose for maximum security? What are the odds of it getting evaded? Such questions always come into the picture whenever a cryptographic technique or scheme is developed. Cryptanalysis is one of the common tools that help to check the credibility and security of a cryptographic algorithm.
Cryptanalysis in done on the basis of the potential vulnerabilities of the scheme and the capabilities that the attackers may have to break the code of security.
Some of the most popular classification of the cryptanalysis are,
- Cipher-text only attacks
The attacker has information about the ciphertext and in practical cases; the attacker has a slight idea about the plaintext as well.
- Known-plaintext attack
The plaintext and the corresponding ciphertext is known to the attacker and they further use it to deduce secret information. Apart from this, there is a chosen plaintext and chosen ciphertext attacks where the attacker knows a particular section of the messages.