Encrypts plaintext of up to 4,096 bytes using a KMS key. You can use a symmetric or
asymmetric KMS key with a
You can use this operation to encrypt small amounts of arbitrary data, such as a personal
identifier or database password, or other sensitive information. You don't need to use the
Encrypt operation to encrypt a data key. The GenerateDataKey
and GenerateDataKeyPair operations return a plaintext data key and an
encrypted copy of that data key.
If you use a symmetric encryption KMS key, you can use an encryption context to add
additional security to your encryption operation. If you specify an
EncryptionContext when encrypting data, you must specify the same encryption
context (a case-sensitive exact match) when decrypting the data. Otherwise, the request to
decrypt fails with an
InvalidCiphertextException. For more information, see
Context in the Key Management Service Developer Guide.
If you specify an asymmetric KMS key, you must also specify the encryption algorithm. The algorithm must be compatible with the KMS key spec.
When you use an asymmetric KMS key to encrypt or reencrypt data, be sure to record the KMS key and encryption algorithm that you choose. You will be required to provide the same KMS key and encryption algorithm when you decrypt the data. If the KMS key and algorithm do not match the values used to encrypt the data, the decrypt operation fails.
You are not required to supply the key ID and encryption algorithm when you decrypt with symmetric encryption KMS keys because KMS stores this information in the ciphertext blob. KMS cannot store metadata in ciphertext generated with asymmetric keys. The standard format for asymmetric key ciphertext does not include configurable fields.
The maximum size of the data that you can encrypt varies with the type of KMS key and the encryption algorithm that you choose.
Symmetric encryption KMS keys
SYMMETRIC_DEFAULT: 4096 bytes
RSAES_OAEP_SHA_1: 214 bytes
RSAES_OAEP_SHA_256: 190 bytes
RSAES_OAEP_SHA_1: 342 bytes
RSAES_OAEP_SHA_256: 318 bytes
RSAES_OAEP_SHA_1: 470 bytes
RSAES_OAEP_SHA_256: 446 bytes
SM2PKE: 1024 bytes (China Regions only)
The KMS key that you use for this operation must be in a compatible key state. For details, see Key states of KMS keys in the Key Management Service Developer Guide.
Cross-account use: Yes.
To perform this operation with a KMS key in a different Amazon Web Services account, specify
the key ARN or alias ARN in the value of the
Required permissions: kms:Encrypt (key policy)