TechFundamentals

Hash Functions & Hashing

• hashing
• take data and create fixed length representation
• unique hash for different data
• can't turn hash into original data
• hash function : algorithm to convert data into string
• collision : if different data get the same hash value

Digital Signatures

• public key cryptography
• public key used to encrypt data
• private key used to decrypt data
• private key can sign data, and public key can verify it
• digital signature
• verifies integrity and authenticity
• hash of data is taken, original data unchanged
• digital sign hash using private key (authenticates the hash)
• use public key to verify the hash signature
  • exposes original hash
• use same algorithm to hash data and see if it matches with the hash exposed by public key