DP44/docs/ai/Common/DTS.Common.Security.md

source_files, generated_at, model, schema_version, sha256

source_files	generated_at	model	schema_version	sha256
Common/DTS.Common.Security/Encryption.cs	2026-04-17T16:38:14.461744+00:00	zai-org/GLM-5-FP8	1	47baa7f78b6a693b

Documentation: DTS.Common.Security.Encryption

1. Purpose

This module provides symmetric AES encryption and decryption utilities for string data. It exists as a stateless helper class to encapsulate the complexity of cryptographic stream operations, allowing callers to encrypt plaintext strings into byte arrays and decrypt them back using a shared key and initialization vector (IV). It serves as a foundational security primitive within the DTS.Common.Security namespace.

2. Public Interface

public static byte[] EncryptStringToBytes(string plainText, byte[] key, byte[] iv)

Encrypts a UTF-8 encoded string into a cipher byte array using AES symmetric encryption.

• Parameters:
  • plainText (string): The clear-text string to encrypt.
  • key (byte[]): The secret key for the symmetric algorithm.
  • iv (byte[]): The initialization vector for the symmetric algorithm.
• Returns: A byte array containing the encrypted cipher text.
• Throws: ArgumentNullException if any argument is null or has a length of zero.

public static string DecryptStringFromBytes(byte[] cipherText, byte[] key, byte[] iv)

Decrypts a cipher byte array back into a UTF-8 encoded string using AES symmetric decryption.

• Parameters:
  • cipherText (byte[]): The encrypted byte array to decrypt.
  • key (byte[]): The secret key used during encryption.
  • iv (byte[]): The initialization vector used during encryption.
• Returns: The decrypted clear-text string.
• Throws: ArgumentNullException if any argument is null or has a length of zero.

3. Invariants

• Null/Empty Checks: All parameters (plainText/cipherText, key, iv) must be non-null and have a length greater than zero; otherwise, an ArgumentNullException is thrown immediately.
• Key/IV Consistency: The caller must provide the exact same key and iv byte arrays for decryption that were used for encryption; otherwise, decryption will fail or produce garbage output.
• Encoding: Text encoding is implicitly UTF-8 (default behavior of StreamWriter and StreamReader used internally).
• Algorithm: The implementation uses AesCryptoServiceProvider for the cryptographic transformation.

4. Dependencies

Direct Dependencies (Imports)

• System - Core types, ArgumentNullException.
• System.IO - MemoryStream, StreamWriter, StreamReader for stream-based processing.
• System.Security.Cryptography - AesCryptoServiceProvider, CryptoStream.

Consumers

• Unknown from source alone. This is a utility class likely consumed by other modules within the `DTS.Common