Data Loss Prevention

  • DLP prevents data loss and theft through information handling policies.
  • Monitors systems for unsecured sensitive information.
  • Acts to block transmission before breaches occur.
  • Two environments: Host-based DLP (software agents on systems) and Network DLP (devices monitoring network traffic).

Goals of Cryptography

  • Three key goals:
      - Confidentiality
      - Integrity
      - Authentication
  • Additional goals: Non-repudiation, secure multi-party computation, anonymity.

Basic Vocabulary

  • Plaintext: Original message.
  • Ciphertext: Coded message.
  • Encryption: Process of converting plaintext to ciphertext.
  • Decryption: Process of recovering plaintext from ciphertext.
  • Symmetric key: Same key used for both encryption and decryption.
  • Asymmetric key: Different keys for encryption and decryption.

Cipher Types

  • Block cipher: Encrypts data in fixed-size blocks.
  • Stream cipher: Encrypts data one byte at a time.
  • Cryptanalysis: Breaking the code using knowledge of the algorithm.

Symmetric Cipher Model

  • Utilizes plaintext, encryption algorithm, secret key, ciphertext, and decryption algorithm.
  • E.g., for encryption: Y = E(K, X).

Substitution Techniques

  • Shift Cipher: Letters shifted by a fixed number, e.g., Caesar Cipher.
  • Vigenère Cipher: Utilizes a keyword to shift letters in varying amounts.

Advanced Techniques

  • One-Time Pad: Unbreakable cipher using a random key, as long as the message.
  • Transposition Techniques: Permutation of plaintext letters (e.g., Rail Fence Technique).

Block Ciphers

  • DES: Legacy standard; 64-bit blocks, 56-bit key.
  • AES: Current standard; 128-bit blocks, key sizes of 128, 192, or 256 bits.

Public-Key Cryptography

  • Uses two keys: public (accessible) and private (secret).
  • RSA: Widely adopted public-key encryption method.
  • Digital signatures provide message authenticity.

Cryptographic Hash Functions

  • Produce fixed-size output from variable-length input.
  • Ensure data integrity and validate message authenticity.
  • Examples: MD5, SHA-1, SHA-2.

Cryptographic Attacks

  • Passive: Eavesdropping.
  • Active: Attempt to determine secret keys (e.g., brute-force, dictionary attacks).
  • Replay: Resubmitting captured data.

Data Minimization

  • Reduce sensitive information maintained.
  • Use techniques like hashing, tokenization, and masking to protect data.
  • Rainbow table attacks can compromise hashing used in data minimization.