MongoDB .local San Francisco 2020: Using Client Side Encryption in MongoDB 4.2

db.coll.insert({
_id: 1,
name: "Doris",
ssn: "457-55-5462"
})

doc = db.coll.find_one({
ssn: "457-55-5462"
})

{
_id: 1
name: "Doris",
ssn: "457-55-5462"
}

db.coll.insert({
name: "Doris",
ssn: "457-55-5462"
})
{
insert: "coll",
documents: [{
name: "Doris",
ssn: BinData(6, "a10x…")
}]
}
You see: MongoDB sees:
Encrypt before sending

{
_id: 1
name: "Doris",
}
Driver receives: You see:
{
_id: 1
name: "Doris",
ssn: "457-55-5462"
}
Decrypt after receiving

How does this differ from…?
•… encryption in-transit (TLS)
•… encryption at-rest (encrypted storage engine)

Attacker
query
App
(Client)
Disk
insert write
MongoDB
Auth
db.coll.insert({ name: "Doris", ssn: "457-55-5462" })

Disk
insert write
MongoDB
Attacker
snoop
TLS
App
(Client)

Disk
insert write
MongoDB
Attacker
insert
TLS
App
(Client)

Disk
insert write
MongoDB
Attacker
steal
ESE
App
(Client)

Disk
insert write
MongoDB
Attacker
login
Client Side Encryption
App
(Client)

Disk
insert write
MongoDB
Boundaries of unencrypted data
App
(Client)

Disk
insert write
MongoDB
… with Encrypted Storage Engine
App
(Client)

Disk
insert write
MongoDB
… and TLS
App
(Client)

Disk
insert write
MongoDB
with Client Side Encryption
App
(Client)

Disk
insert write
MongoDB
App
(Client)

db.coll.update({}, {
$set: { ssn: "457-55-5462" }
})
{
update: "coll",
updates: [{
q:{},
u: {
$set: { ssn: BinData(6, "a10x…") }
}
}]
}
Update that overwrites value

db.coll.aggregate([{
$project: { name_ssn: {$concat: [ "$name", " - ", "$ssn" ] } }
}]
Aggregate acting on the data

Find with equality query
* For deterministic encryption
db.coll.find({ssn: "457-55-5462" }) {
find: "coll",
filter: { ssn: BinData(6, "a10x…") }
}

db.test.find(
{
$and: [
{
$or: [
{ ssn : { $in : [ "457-55-5462", "153-96-2097" ]} },
{ ssn: { $exists: false } }
]
},
{ name: "Doris" }
]
}
)
You see:

MongoDB sees:
{
find: "coll",
filter: {
$and: [
{
$or: [
{ ssn : { $in : [ BinData(6, "a10x…"), BinData(6, "8dk1…") ]} },
{ ssn: { $exists: false } }
]
},
{ name: "Doris" }
]
}
}

Destroy the key
Provably delete all user data.
GDPR "right-to-be-forgotten"

Doris
Private stuff in storage

PoliceDoris
Private stuff in storage

Vault key
Held only by you
Vault

Encrypted Data
MongoDB
Encryption Key

{ _id: 1, ssn: BinData(0, "A81…"), name: "Kevin" }
{ _id: 2, ssn: BinData(0, "017…"), name: "Eric" }
{ _id: 3, ssn: BinData(0, "5E1…"), name: "Albert" }
…

client = MongoClient(
auto_encryption_opts=opts)

{
name: "Doris"
ssn: "457-55-5462",
email: "Doris@gmail.com",
credit_card: "4690-6950-9373-8791",
comments: [ …. ],
avatar: BinData(0, "0fi8…"),
profile: { likes: {…}, dislikes: {…} }
}

Describes JSON
{
bsonType: "object",
properties: {
a: {
bsonType: "int"
maximum: 10
}
b: { bsonType: "string" }
},
required: ["a", "b"]
}
{
a: 5,
b: "hi"
}
{
a: 11,
b: false
}
JSON Schema

{
bsonType: "object",
properties: {
ssn: {
encrypt: { … }
}
},
required: ["ssn"]
}
JSON Schema "encrypt"

encrypt: {
keyId: (…),
algorithm: (…),
bsonType: (…)
}
bsonType indicates the type of underlying data.
algorithm indicates how to encrypt (Random or Deterministic).
keyId indicates the key used to encrypt.

opts = AutoEncryptionOptions(
schema_map = { "db.coll": <schema> }
…)

Remote Schema Fallback
db.createCollection("coll", { validator: { $jsonSchema: … } } )
Misconfigured
Client insert "457-55-5462"
error, that should be
encrypted
MongoDB

What if
… the server lies about the schema?
Misconfigured
Client insert "457-55-5462"
Evil MongoDB
ok :)

Key vault
Key vault key
Held only by you

schema_map = { "db.coll": <schema> },
key_vault_namespace = "db.keyvault"
…)

schema_map
Sub-options
key_vault_namespace

What if
… attacker drops key vault collection?

Keep at home
key_vault_namespace = "db.keyvault",
key_vault_client = <client>
…)

schema_map
Sub-options
key_vault_namespace
key_vault_client

Protects keys Stores keys
KMS
Key vault key
Key vault
Key vault
collection

key_vault_namespace = "db.keys",
kms_providers = <creds>
…)

schema_map
Sub-options
key_vault_namespace
key_vault_client
kms_providers

db.coll.insert({
name: "Doris",
ssn: "457-55-5462"
})
Get encrypted key
Decrypt the key with KMSDecrypt the key with KMS
Encrypt 457-55-5462
Send insert
Compare to JSON schema

You need…
•MongoDB 4.2 server
•Beta client (shell, Java, Python, NodeJS, Go, C#)
•Enterprise license for auto encryption
•Community for explicit encryption

Authenticated Encryption with Associated Data using the Advance

AEAD_AES_256_CBC_HMAC_SHA_512
Provides confidentiality + integrity

AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic
AEAD_AES_256_CBC_HMAC_SHA_512-Random

coll.insert({ ssn: "457-55-5462" }) { ssn: BinData(6, "a10x…") }
You see: MongoDB stores:
coll.insert({ ssn: "457-55-5462" }) { ssn: BinData(6, "f991…") }
…Random

You see: MongoDB stores:
…Deterministic

Can be queried
doc = db.coll.find({
ssn: "457-55-5642"
})
…Deterministic

Only for binary comparable types.
db.coll.find({ a: NumberDecimal("1.2")})
{ a: NumberDecimal("1.2") }
MongoDB returns:
…Deterministic

{ a: BinData(6, "b515…") }
{ a: BinData(6, "801f…") }
Encrypted as:
Value:

db.coll.find({ a: NumberDecimal("1.2") })
MongoDB returns:
"a" encrypted

Encrypt-able values
Deterministic encryption valid for…
•String
•Binary
•ObjectID
•Date
•Regex
•DBPointer
•Javascript
•Symbol
•Int
•Timestamp
•Long
Random encryption valid for…
•(all of deterministic)
•Document
•Array
•JavascriptWithScope
•Double
•Decimal128
•Bool

{ ssn: BinData(6, "AWNkTYTCw89Ss1DPzV3/2pSRDNGNJ9NB" }
New binary subtype
Older drivers and older MongoDB will treat as a black box.

byte algorithm
byte[16] key_id
byte original_bson_type
byte* payload
Ciphertext

byte algorithm
byte[16] key_id
byte* payload
key_id + algorithm describes how to decrypt.
No JSON Schema necessary!
Ciphertext

byte algorithm
byte[16] key_id
byte* payload
Provides extra server-side validation.
But prohibits single-value types (MinKey, MaxKey, Undefined, Null)
Ciphertext

byte algorithm
byte[16] key_id
byte* payload
Payload includes encoded IV and padding block, and HMAC.
Ciphertext adds between 66 to 82 bytes of overhead.
Ciphertext

ce = ClientEncryption(opts)
encrypted = ce.encrypt("457-55-5462", opts))
decrypted = ce.decrypt(BinData(6, "a10x…")))
id = ce.createDataKey(opts)

db.test.find({
$or: [
{ ssn : { $in : [ "457-55-5462", "153-96-2097" ]} },
{ name: "Doris" }
]
})
db.test.find({
$or: [
{ ssn : { $in : [ BinData(6, "a10x…"), BinData(6, "8dk1…") ]} },
{ name: "Doris" }
]
})

Limitations
If we cannot parse…
or it is impossible…
we err for safety.

{ passport_num: "281-301-348", ssn: "457-55-5462" }
{ passport_num: "390-491-482", ssn: "482-38-5899" }
{ passport_num: "104-201-596" }
passport_num and ssn encrypted with different keys

db.test.aggregate([
])
{ $project: { identifier: { $ifNull: ["$ssn", "$passport_num" ] } } },
{ $match: { identifier: "457-55-5462" } }
How do we encrypt 457-55-5462?

bypass_auto_encryption = True
…)
client = MongoClient(auto_encryption_opts=opts)
(Decryption still occurs)

db.test.aggregate([
])
{ $project: { identifier: { $ifNull: ["$ssn", "$passport_num" ] } } },
{ $match: { identifier: ce.encrypt("457-55-5462", opts) } }

One key
id = ce.createDataKey(keyopts)
Create with ClientEncryption

One key
Specify with JSONSchema
…
ssn: {
encrypt: {
keyId: [id],
algorithm: (…),
bsonType: (…)
}
}

One key
db.coll.insert({
name: "Doris",
ssn: "457-55-5462"
})
Query key vault by _id

Labeled keys
id = ce.createDataKey(keyopts, keyAltNames=["Doris"])
Create with ClientEncryption

Labeled keys
Specify JSON Pointer with JSONSchema
…
ssn: {
encrypt: {
keyId: "/name",
algorithm: (…),
bsonType: (…)
}
}

db.coll.insert({
name: "Doris",
ssn: "457-55-5462"
})
Query key vault by label "Doris"
Labeled keys

db.coll.insert({
name: "Kevin",
ssn: "457-55-5462"
})
Query key vault by label "Kevin"
Labeled keys

DorisDB
MongoDB Cloud Hosting - By Doris ™

App Server
User
insert
MongoDB
(Key Vault)
fetch key
decrypt key DorisDB
(Storage)
encrypted insert

{
email: (encrypted),
pwd: (encrypted)
}
Email deterministic, pwd random, uses collection key

{
user_id: "…",
title: (encrypted),
body: (encrypted)
}
Encrypted randomly with per-user key

User
MongoDB
(Key Vault)
delete user key
DorisDB
(Storage)
delete all posts
App Server
"Delete my data"
… but was it really deleted?

EAST
DICTATORLAND
Global Shards

EAST
DICTATORLAND
{ _id: 1, body: BinData(6, "A81…") }
{ _id: 2, body: BinData(6, "017…") }
{ _id: 3, body: BinData(6, "5E1…") }
…

MongoDB .local San Francisco 2020: Using Client Side Encryption in MongoDB 4.2

MongoDB .local San Francisco 2020: Using Client Side Encryption in MongoDB 4.2

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MongoDB .local San Francisco 2020: Using Client Side Encryption in MongoDB 4.2