CTR

Definition

CTR (Counter) mode is a symmetric key block cipher encryption mode that turns a block cipher into a stream cipher. It generates the next keystream block by encrypting successive values of a counter. This mode allows for parallel encryption of blocks, making it efficient and suitable for high-speed network encryptions. However, it is crucial to use a unique counter value for each encryption operation to maintain security.

Secure Settings Example

encryption:
  mode: CTR
  key: "your-secure-key-here"
  nonce: "unique-nonce-per-operation"
  counter: 0

In this example, a unique nonce is used for each encryption operation, ensuring that the counter value does not repeat, which is critical for maintaining the security of CTR mode.

Insecure Settings Example

encryption:
  mode: CTR
  key: "your-secure-key-here"
  nonce: "fixed-nonce"
  counter: 0

Using a fixed nonce across multiple encryption operations can lead to vulnerabilities, as it may result in the reuse of keystream blocks, compromising the confidentiality of the encrypted data.