Flashcards
Hashing
Cards in this deck (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
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- A level OCR A level Computer Science (Topic 4 - Exchanging Data) Flashcards on Hashing, created by James Norman on 28/01/2020.
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- James Norman
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