1 Data processing and information

• Data


  Raw numbers, letters, symbols, sounds or images without meaning
• Information


  Data with context and meaning
• When data items are given context and meaning, they become information
• Direct data source


  Data that is collected for the purpose for which it will be used
• Examples of direct data source

  Questionnaires, interviews, data logging
• Indirect data source


  Data that was collected for a different purpose
• Example of indirect data source

  Businesses collecting information used by third parties

  Electoral register
• Disadvantages of direct data source

  Takes a long time to gather original data

  Large sample of statistical data can be difficult to collect
• Advantages of indirect data source

  Data is immediately available

  In statistical analysis there are more likely to be large samples available
• Disadvantages of indirect data source

  Data may be out of date

  Additional data not required may exist and data required may not exist

  Original source may not be known so may not be reliable

  Data may be biased

  Data is unlikely to be in the format required which can make extracting the data difficult
• Factors that affect the quality of information

  Accuracy

  Relevance

  Age

  Level of detail

  Completeness
• Accuracy

  Data must be accurate to be considered good quality
• Relevance

  Information must be relevant to its purpose
• Age

  Information must be up to date in order to be useful
• Level of detail

  There needs to be the right amount of information for it to be good quality. There could be too much or too little.
• Completeness

  All information that is required must be provided in order for it to be good quality
• Encryption is scrambling data so it cannot be understood without a decryption key to make it unreadable if intercepted.
• Advantages of encryption

  Helps protect and store private information and sensitive data from hackers

  It can enhance the security of communication between client apps and servers
• Disadvantages of encryption

  The need for additional resources and costs to implement and maintain

  Introducing risks and complexity to data management

  Can affect the speed and efficiency of data processing and analysis

  Limit the visibility and usability of data
• Symmetric encryption


  Requires both sender and recipient to possess the private key

  The private key needs to be sent to the recipient

  Could be intercepted by hackers
• Asymmetric encryption


  Uses two different keys

  Includes a public key which is available to anyone wanting to send data

  Includes a private key only known to the recipient to decrypt the data
• Advantages of symmetric encryption

  Fast

  Extremely secure
• Disadvantages of symmetric encryption

  Private key needs to be sent
• Advantages of asymmetric encryption

  Allows message authentication

  More secure than symmetric
• Disadvantages of asymmetric encryption

  Slow
• Public key is a key that may be used by anyone wanting to encrypt and transfer data
• Private key is a secret key that can only be accessed by the recipient and is used to unlock information they received
• Digital certificates are required which identify the user or server and provide the public key.
• A digital certificate includes:

  Organization name

  Organization that issued the certificate

  User's email address

  User's country

  User's public key
• Asymmetric encryption is used for

  SSL: secure socket layer

  TLS: transport layer security
• Symmetric encryption is faster than asymmetric encryption
• Advantages of direct data source

  • Data is relevant
  • Original source is known so it can be trusted
  • Data is likely to be up-to-date
  • Data can be collected and presented in the required format
  • Bias can be eliminated by asking specific questions
• Uses of encryption

  Hard disk:

  • encrypts every single bit of data stored on the disk
  • to access any file on the disk, the encryption key will be required
  • use on backup tapes and universal serial bus (USB)
  • this data is usually accessed by entering a password or using a fingerprint
• Uses of encryption

  HTTPS:

  • hypertext transfer protocol secure is the encryption standard used for secure web pages
  • uses SSL and TLS to encrypt or decrypt information sent and received by web users
• Process of HTTPS

  • browser requests a secure page
  • checks digital certificate to ensure trust and validation
  • browser uses public key to encrypt new symmetric key
  • browser and web server communicate using symmetric encryption key which is faster than asymmetric
• Uses of encryption

  Email:

  • uses asymmetric encryption
  • recipients of email must have the private key that matches the public key used to encrypt the email
  • encrypting an email will also encrypt any attachments
• Validation is the process of checking data matches acceptable rules
• Verification ensures data entered into the system matches the original source
• Validation

  • presence check
  • range check
  • type check
  • length check
  • lookup check
  • consistency check
  • check digit
  • format check
• Verification

  • visual checking
  • double data entry
  • hash total
  • control total
  • parity check
  • checksum