keyMaterialId

Identifies the key material being imported. This parameter is optional and only usable with symmetric encryption keys. You cannot specify a key material ID with ImportType set to NEW_KEY_MATERIAL. Whenever you import key material into a symmetric encryption key, KMS assigns a unique identifier to the key material based on the KMS key ID and the imported key material. When you re-import key material with a specified key material ID, KMS:

• Computes the identifier for the key material

• Matches the computed identifier against the specified key material ID

• Verifies that the key material ID is already associated with the KMS key

To get the list of key material IDs associated with a KMS key, use ListKeyRotations.