Encrypts data on the server side with a new customer master key without exposing the plaintext of the data on the client side. The data is first decrypted and then encrypted. This operation can also be used to change the encryption context of a ciphertext.

Unlike other actions, ReEncrypt is authorized twice - once as ReEncryptFrom on the source key and once as ReEncryptTo on the destination key. We therefore recommend that you include the "action":"kms:ReEncrypt*" statement in your key policies to permit re-encryption from or to the key. The statement is included automatically when you authorize use of the key through the console but must be included manually when you set a policy by using the PutKeyPolicy function.