sourceEncryptionContext
Specifies the encryption context to use to decrypt the ciphertext. Enter the same encryption context that was used to encrypt the ciphertext.
An encryption context is a collection of non-secret key-value pairs that represent additional authenticated data. When you use an encryption context to encrypt data, you must specify the same (an exact case-sensitive match) encryption context to decrypt the data. An encryption context is supported only on operations with symmetric encryption KMS keys. On operations with symmetric encryption KMS keys, an encryption context is optional, but it is strongly recommended.
For more information, see Encryption context in the Key Management Service Developer Guide.