Which cryptographic algorithm is used in Blockchain?

Blockchain uses SHA-256 Hashing algorithm. The National Security Agency (NSA) in the USA develop SHA-256 Hashing algorithm.

The most commonly used cryptographic algorithm in blockchain is the SHA-256 (Secure Hash Algorithm 256-bit). It is widely employed for creating hash functions that provide the necessary security and integrity for various aspects of blockchain technology, including creating blocks and ensuring the immutability of the data within the blocks. Additionally, other cryptographic algorithms, such as ECDSA (Elliptic Curve Digital Signature Algorithm), are often used for digital signatures in blockchain transactions to ensure authenticity and security.