SLR 9/ Compression, Encryption and Hashing Flashcards
Define Lossy Compression
Algorithm used to strip out least important data. Typically used for multimedia files. Original file cannot be restored. Examples: JPEG, MP3, MPEG
Define Lossless Compression
Typically less effective at reducing file size. Essential for some file types such as computer programs. Original file can be restored. Examples: ZIP, PNG, GIF
Define Generic Compression
Reduces download times. Reduces requirements on file storage. Makes best use of bandwidth
Define Symmetric Encryption
The data has an encryption key and a decryption key is used to decrypt the data. there are only 1 key for encryption and 1 for decryption.
Define Asymmetric Encryption
The data has a public key and a senders private key. Combine them to make combined key used for the encryption. then once encrypted it uses again the public key and the recipients private key to get the data.
“Hashing and encryption are essentially the same thing, as they turn plain text into an unreadable format.” Explain what is wrong with this statement.
A hash is a string or number generated from a string of text. Hashing algorithms are designed to be one way, so it should be impossible to turn a hashed value back into the original text. Hashing is different from encryption in that an encrypted message can be reversed back into the original message if you posses the correct key.
Provide a good example of what hashing is used for and justify your answer.
Storing passwords because hashes are one-way. If a password is stored in a hashed format, it should be very difficult to regenerate the original password.It is good in any situation where you need to compare a value with a stored value but you can’t store the plain text version for security and privacy reasons
What is salt and how is it used with hashing algorithms?
A random data item often used as an additional input to hashing algorithms. It helps generate extra secure hashed values
