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SLR 9 - Compression, Encryption and Hashing
Fichas del conjunto (16)
- 1CompressionReducing the size of files
Often makes the best use of internet bandwidth when uploading or downloading - 2Lossy CompressionSome data is removed from the file to reduce the size
An algorithm is used to dete the least important data
Original file cannot be restored - 3Lossless CompressionAll data is retained but encoded in a way that the file size is reduced and can be restored
Less effective as lossy
Essential for some files - 4Dictionary EncodingBuilds an index which stores every unique data item (each with its own index reference)
The compressed file consists of the dictionary index and the sequence that the data occurs in - 5Run Length EncodingAdjacent repeated items are stored once with an index of how many times it is repeated
E.g. 0 0 0 0 0 = 0 5 - 6EncryptionThe process of encoding a message so that it can only be read by the sender and intended participant
- 7Symmetric EncryptionThe same key is used to both encrypt and decrypt the data
Both parties need to know the key - 8Asymmetric EncryptionTwo keys are needed (One to encrypt it and another to decrypt)
You cannot work out what the other key is from a single key - 9Key PairsA pair of encryption and decryption keys which are used together one is public and one is private
- 10Public KeyThe key can be shared with others, stored online and anyone can get access to it
- 11Private keyA key which is kept entirely secret and not shared with anyone
- 12Combined Key EncryptionThe sender's private key and the recipients public key form a combined key they can then use their combine encryption key to decrypt the message
- 13HashingThe processed used to transform data into something different
- 14Uses of HashingGenerating disk addresses for storing data on RAM
Storing and Checking Passwords
However, hashing makes programs more complex and slower - 15Hashing and PasswordsA hashing algorithm is applied to the password and then stored
When a user puts in their password the same algorithm is applied and if the result is the same then the user is allowed access - 16SaltingProcess used in hashing to ensure that passwords are unique
Salt is random data added to the start or end of an input to a hash before being hashed to ensure the value is unique
(E.g. If 2 users had the same password)
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- Descripción
- Fichas sobre SLR 9 - Compression, Encryption and Hashing, creado por Declan Gallagher el 13/01/2020.
- Creado por
- Declan Gallagher
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