What is cryptography?
Cryptography is the practice and study of techniques for securing communication and data from unauthorized access and ensuring data integrity, confidentiality, and authenticity. It involves creating and analyzing protocols that prevent third parties from accessing or altering information. Cryptography encompasses various methods, including encryption (transforming data into a secure format), decryption (reverting encrypted data to its original form), digital signatures (verifying the authenticity of a message or document), and hashing (producing a fixed-size string or hash from data, which represents the data uniquely). Cryptography is essential for securing online transactions, protecting sensitive information, and maintaining privacy in digital communications.
what is hashing?
Hashing is a process in cryptography that transforms any input data, regardless of its size, into a fixed-size string of characters, typically a sequence of numbers and letters. This output is known as a hash value or hash code. Hashing is commonly used to ensure data integrity, authenticate information, and store data securely.
Key properties of hashing include:
- Deterministic: The same input will always produce the same hash value.
- Fast computation: Hash functions are designed to be computationally efficient.
- Pre-image resistance: Given a hash value, it should be difficult to reverse-engineer the original input.
- Small changes in input produce significant changes in output: Even a tiny modification in the input should result in a drastically different hash value.
- Collision resistance: It should be challenging to find two different inputs that produce the same hash value.
Hashing is widely used in various applications such as password storage, data integrity checks, and digital signatures. Common hash functions include MD5, SHA-1, and SHA-256.






























































































