Decrypts data using a CMK.
This method decrypts data using the CMK specified by KeyId and the given Algorithm. The data to decrypt is taken from the input stream supplied via the SetInputStream method, the specified InputFile, or the InputData property. The decrypted data is output to the output stream supplied via the SetOutputStream method, the specified OutputFile, or the OutputData property.
The value passed for the KeyId parameter must be the Id or ARN of a CMK, or the name or ARN of an alias, in the current Region. If an ARN is provided, it can be for a CMK or alias in another account so long as the appropriate permissions are in place.
The Algorithm parameter specifies which algorithm to use to decrypt the data; it must match the algorithm used to encrypt the data previously. Possible values vary depending on the specified CMK's key spec:
|CMK's Key Spec||Valid Algorithms|
|SYMMETRIC_DEFAULT||SYMMETRIC_DEFAULT (default if empty)|
If Algorithm is SYMMETRIC_DEFAULT, the encryption context items in the EncryptionContext collection will be included in the request. Keep in mind that in order to successfully decrypt the data, the exact same encryption context items that were present when the data was encrypted must be supplied again. Encryption context items are case-sensitive, but not order-sensitive.
This method will fail if any of the following are true regarding the specified CMK:
- Its State is anything other than aksEnabled (0).
- It is for signing/verification instead of encryption/decryption (see ForSigning).
- It is an AWS-managed CMK (see AWSManaged).