Flashcards

Hashing

James Norman OCR A level Computer Science A level Inglês 7 flashcards

Flashcards do conjunto (7)

1Explain what is meant by a hash function/algorithmA function/algorithm which takes a variable-length input and produces an output (usually fixed-length) derived from the value of that input
The function/algorithm is one-way and therefore the input cannot be deduced from the output
2Explain what is meant by a hash digest/total/checksumThe output value of a hash function
3Uses of hashing1. Storing PINs and passwords
2. Verifying content (prevents data from being tampered with)
3. Digital signatures
4. Indexing hash tables (covered later)
4Cryptographically secure hash functionsThese are more complex and often slower than other functions
More difficult to reverse than other hash functions
5Digital signaturesIt is possible for a 3rd party to falsify or alter data in an exchange via the Internet (a man-in-the-middle or MITM attack)
To combat this, a digital signature is used
This uses the sender's private key to encrypt a hash digest of the message
This can be decrypted with the sender's public key and compared with a hash of the received data to verify its contents
6Digital CertificatesDigital signatures can only verify the trustworthiness of message content, not the sender
A third party, known as a Certificate Authority (CA), holds certificates that contain information about the sender to verify them
7Digital Certificate contents1. Certificate's serial number
2. Expiry data
3. Name of the holder
4. Copy of the holder's public key
5. Digital signature of the CA

Descrição: A level OCR A level Computer Science (Topic 4 - Exchanging Data) FlashCards sobre Hashing, criado por James Norman em 28-01-2020.
Criado por: James Norman
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