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• Public Key Cryptography


  A two-key system where a key pair (public and private key) is used for encryption and decryption.
• Public key


  Widely distributed and allows anyone to encrypt messages to the key owner.
• Private Key


  Kept secret by the key owner and used to decrypt messages encrypted with the public key.
• Advantages of PKC


  Secure communication

  Digital signatures
• adv-Secure communication


  Anyone can send secure messages to the key owner without needing a shared secret key.
• adv-Digital signatures


   The private key can be used to create digital signatures for messages, verifying the sender's identity and message integrity.
• rivest shamir adleman (RSA)


  A popular PKC Algorithm

  Key Generation

  Security
• RSA-A popular PKC algorithm


  Uses complex mathematical functions based on large prime numbers for encryption and decryption. d
• RSA-Key Generation


  Creates a public-private key pair through complex calculations involving prime numbers.
• RSA-Security


  Relies on the difficulty of factoring large prime numbers. If factoring becomes easy, RSA could be broken.
• Hybrid Encryption


  Combines PKC and Symmetric Key Encryption:

  Uses PKC for secure key exchange (distributing a secret key).

  Uses a symmetric key algorithm (like AES) for bulk encryption due to its efficiency.
• SSL


  Secure Sockets Layer, is an encryption-based Internet security protocol. It was first developed by Netscape in 1995 for the purpose of ensuring privacy, authentication, and data integrity in Internet communications.
• How does SSL work

  encrypts data that is transmitted across the web. This means that anyone who tries to intercept this data will only see a garbled mix of characters that is nearly impossible to decrypt.
• Benefits of hybrid encryption

  1. Secure Key Exchange: PKC ensures the secret key is securely delivered to the recipient using their public key.
  2. Efficient Encryption:Symmetric key algorithms are faster for encrypting large amounts of data
• Public Lock (Public key)


   Anyone can put a message in (encrypt) using a widely available key.
• Private lock (Private key)


  Only the mailbox owner has the key (private key) to unlock (decrypt) messages.
• Hybrid encryption


  Sender encrypts the message with a secret key (like a padlock). Sender encrypts the secret key with the receiver's public key and sends both parts. Receiver uses their private key to decrypt the secret key. Receiver uses the decrypted secret key to decrypt the message.
• Symmetric key encryption


  type of encryption where only one key (a secret key) is used to both encrypt and decrypt electronic information.
• Asymmetric Key encryption


  anyone can encrypt messages using a public key, but only the holder of the paired private key can decrypt such a message.
• Storage of keys in the cloud

  Storing encryption keys securely in the cloud is tricky because cloud resources constantly change.

  Secret sharing offers a solution: it splits a key into multiple pieces (shares) and stores them on different servers. Even if an attacker finds some shares, they can't recreate the key without enough pieces.
• Disadvantages of symmetric key cryptography

  Key distribution

  Key storage and recovery

  open systems
• Key distribution


  Sharing secret keys securely is difficult. Traditional methods like a trusted controller or secure channels aren't very practical.
• Key storage and recovery

  Storing many keys securely is a problem, especially on central servers vulnerable to attacks. Recovering lost keys can also be an issue.
• Scalability


  Symmetric cryptography works best in closed environments with few users. It becomes cumbersome and insecure in large organizations with many users and remote access needs.
• Open systems


  In open environments like large corporations, it's hard to guarantee the authenticity and integrity of keys and encrypted messages.
• data integrity


  accuracy, completeness, and consistency of data over time. It also encompasses data security and regulatory compliance.
• why data integrity is important

  Ensures information stored in a database is reliable and trustworthy. This is important for making informed decisions, meeting legal requirements, and protecting sensitive data.
• Two types of data integrity

  physical

  logical
• Data integrity


  Wholeness and Accuracy of Data Overall concept: Data integrity ensures data remains accurate, complete, and reliable over its lifecycle (storage, retrieval, usage). It encompasses physical and logical integrity.
• Physical integrity


  Protection from Physical Threats

  Focus: Protects data from physical damage or loss due to disasters, power outages, or hardware failures.

  Examples: Backups, disaster recovery plans, and secure storage facilities.
• Logical Integrity


  Maintains data consistency and accuracy as it's used in different ways within a relational database. Protects against human errors and unauthorized modifications.
• 4 types of logical integrity

  Entity Integrity

  Referential Integrity

  Domain Integrity

  User-Defined Integrity
• Entity integrity


  Uses primary keys to uniquely identify data entries and prevent duplicates or missing values (nulls).
• Referential integrity


  Ensures relationships between tables are valid. Foreign keys reference primary keys in other tables to maintain consistency.
• Domain integrity


  Restricts data entered in a column to a predefined set of valid values.
• User defined integrity


  Allows users to create custom rules for specific data manipulation needs.
• multi-prolonged approach needed - unauthorized changes to data

  automatic change detection

  granular change information

  change request correlation

  insufficient data handling

  collecting all challenges
• automatic change detection


  Continuously monitor the entire system to identify any changes, regardless of location or source.
• granular change information


  Gather detailed information about each change, including what changed, by whom, and when.
• change request correlation


  Compare actual changes to approved change requests to identify discrepancies.