ClientEncryption.decrypt()

New in version 4.2.

beta

Client-Side Field Level Encryption is available as a beta. The contentsof this page may change during the beta period.

  • ClientEncryption.decrypt(encryptedValue)
  • ClientEncryption.decrypt decrypts the encryptionValue _if_the current database connection was configured with access to the KeyManagement Service (KMS) and key vault used to encrypt encryptionValue.

decrypt has the following syntax:

  1. clientEncryption = db.getMongo().getClientEncryption()
  2.  
  3. clientEncryption.decrypt(encryptedValue)

The encryptedValue must be a binary data objectwith subtype 6created using client-side field level encryption.

returns:The decrypted value.

Behavior

Read operations issued from a database connection configuredwith access to the correct Key Management Service (KMS) and Key Vault canautomatically decrypt field values encrypted usingClientEncryption.encrypt(). Clients only need to usedecrypt() to decrypt Binary subtype 6values not stored within a document field.

Enable Client-Side Field Level Encryption on Database Connection

The mongo client-side field level encrytion methodsrequire a database connection with client-side field level encryptionenabled. If the current database connection was not initiated withclient-side field level encryption enabled, either:

  • Use the Mongo() constructor from the mongoshell to establish a connection with the required client-side fieldlevel encryption options. The Mongo() method supports bothAmazon Web Services and Local Key Management Service (KMS) providersfor Customer Master Key (CMK) management.

or

  • Use the mongo shell command line options to establish aconnection with the required options. The command line options onlysupport the AWS KMS provider for CMK management.

Example

The following example uses a locally managed KMS for the client-sidefield level encryption configuration.

Configuring client-side field level encryption for a locallymanaged key requires specifying a base64-encoded 96-bytestring with no line breaks. The following operation generatesa key that meets the stated requirements and loads it intothe mongo shell:

  1. TEST_LOCAL_KEY=$(echo "$(head -c 96 /dev/urandom | base64 | tr -d '\n')")
  2.  
  3. mongo --nodb --shell --eval "var TEST_LOCAL_KEY='$TEST_LOCAL_KEY'"

Create the client-side field level encryption object using thegenerated local key string:

  1. var ClientSideFieldLevelEncryptionOptions = {
  2.   "keyVaultNamespace" : "encryption.__dataKeys",
  3.   "kmsProviders" : {
  4.     "local" : {
  5.       "key" : BinData(0, TEST_LOCAL_KEY)
  6.     }
  7.   }
  8. }

Use the Mongo() constructor to create a database connectionwith the client-side field level encryption options. Replace themongodb://myMongo.example.net URI with the connection stringURI of the target cluster.

  1. encryptedClient = Mongo(
  2.   "mongodb://myMongo.example.net:27017/?replSetName=myMongo",
  3.   ClientSideFieldLevelEncryptionOptions
  4. )

Retrieve the ClientEncryption objectand use the ClientEncryption.decrypt() method to decrypta value encrypted by ClientEncryption.encrypt().

  1. clientEncryption = encryptedClient.getClientEncryption();
  2.  
  3. clientEncryption.decrypt(BinData(6,"AmTi2H3xaEk8u9+jlFNaLLkC3Q/+kmwDbbWrq+h9nuv9W+u7A5a0UnpULBNZH+Q21fAztPpU09wpKPrju9dKfpN1Afpj1/ZhFcH6LYZOWSBBOAuUNjPLxMNSYOOuITuuYWo="))

If successful, decrypt() returns thedecrypted value:

  1. "123-45-6789"

For complete documentation on initiating MongoDB connections withclient-side field level encryption enabled, see Mongo().