Crypto-Options on AWS | Security Roadshow Dublin

1. ©Amazon.com, Inc. and its affiliates. All rights reserved.
Crypto-Options on AWS
Ronan Guilfoyle - Solutions Architect
Amazon Web Services Ireland

2. Agenda
• Theory
• Options

3. Data
The Cryptographic Trinity
Key
Algorithm
If you don’t own all three parts of the solution, your
data is not considered to be “hard” encrypted…

4. • So what data might I be concerned with?

5. In Region I:
Availability Zone
AWS DC
Availability Zone
AWS DC

6. In Region II:
AWS DC
AWS DC
Availability Zone
AWS DC
AWS DC
Availability Zone

7. Between Regions:
Region
Availability Zone
Availability Zone
Region
Availability Zone
Availability Zone
Public
Customer
WAN
DX Site
DX Site
Here be
Dragons!

8. Summary
• Data in transit within an AZ might leave the building
• Data in transit between AZs will leave the building
• Data in transit between AWS Regions or between AWS and
customer premises needs to be taken care of, too
Encrypt Your Data in Flight

9. Discussion Points
• Hard encryption might be excessive, for some purposes
• Find out where you need which kind of encryption – map your view
of risk and need
• Think about the lifetime of your data (example: German expiry of
use of 3DES and resulting requirement for bulk data re-encryption
with stronger algorithm…)
• Sometimes encryption is only there for Compliance reasons…
Work on your data classification
Find balance between your obligation for
executive care, cost and complexity

10. What about data at rest?
Getting Data at rest encrypted on AWS
is so easy that you should consider a policy:
All data can (an should) be encrypted at rest!

11. Some AWS services supporting data at rest encryption
Technology Partners Consulting Partners AWS MarketplaceEcosystem
Elastic Beanstalk for Java, Node.js, Python,
Ruby, PHP and .Net
OpsWorks CloudFormationContainers & Deployment (PaaS)
Management &
AdministrationIAM CloudWatchCloudTrail APIs and SDKsManagement ConsoleCloud HSM Command Line Interface
Direct Connect Route 53VPC
Networking
Analytics
Data PipelineRedshiftEMR Kinesis SWFSNS SQS CloudSearchSES AppStreamCloudFront
Application Services
WorkSpaces
Regions Availability Zones Content Delivery POPs
Storage GatewayS3 EBS Glacier Import/Export DynamoDB ElastiCache
StorageCompute Databases
RDS
MySQL, PostgreSQL
Oracle, SQL Server
Elastic Load BalancerEC2 Auto Scaling
+

12. AWS Key Management Service I
• Designed for Scalability and Throughput
• Uses bespoke AWS hardware + software
• Is a multi-tenant service
• Performs AES256 operations
• API for crypto command:
– Key Management
– Encryption / Decryption
• Customer selects MasterKey
• Data Key is transported via envelope
encryption
• Durability equal to that of the highest
durability services in AWS
Customer Master
Key(s)
Data Key 1
Amazon
S3 Object
Amazon EBS
Volume
Amazon
Redshift
Cluster
Data Key 2 Data Key 3 Data Key 4
Custom
Application
AWS KMS

13. AWS Key Management Service II
Reference Architecture
Application or
AWS Service
+
Data Key Encrypted Data Key
Encrypted
Data
Master Key(s) in
Customer’s Account
AWS
Key Management Service
1. Application or AWS service client requests an encryption key to use to encrypt data, and passes a
reference to a master key under the account.
2. Client request is authenticated based on whether they have access to use the master key.
3. A new data encryption key is created and a copy of it is encrypted under the master key.
4. Both data key and encrypted data key are returned to the client. Data key is used to encrypt customer data
and then deleted as soon as is practical.
5. Encrypted data key is stored for later use and sent back to AWS KMS when the source data needs to be
decrypted.

14. S3 (normal mode)
AWS AZ
AWS AZ
AWS AZ
• Data is sent to S3 encrypted
• S3 stores the data unencrypted
• Data travels unencrypted between AZs
• Enforce https:
{
"Statement": [{
"Effect": "Deny”,
"Action": "s3:*",
"Condition": {
"Bool": { "aws:SecureTransport": false }
},
"Resource": "arn:aws:s3:::bucket/*"
]}
}

15. S3 (server-side encryption)
AWS AZ
AWS AZ
AWS AZ
• Data is sent to S3 encrypted
• S3 encrypts data with AWS owned key
• Data travels encrypted between AZs
• Data at rest is encrypted with AWS-owned key
• Enforce at-rest encryption:
{
"Statement":[{
"Sid":"DenyUnEncryptedObjectUploads",
"Effect":"Deny",
"Principal":"*",
"Action":"s3:PutObject",
"Resource":"arn:aws:s3:::YourBucket/*",
"Condition":{
"StringNotEquals":{
"s3:x-amz-server-side-encryption":"AES256"
} } } ] }

16. S3 (server-side, user key)
AWS AZ
AWS AZ
AWS AZ
• Data is sent to S3 encrypted
• S3 encrypts data with customer key sent in request
– The key will be forgotten by AWS immediately
• Data travels encrypted between AZs
• Data at rest is encrypted with customer-owned key
• Customer needs to send key in GET request

17. S3 (server-side, user key + KMS)
AWS AZ
AWS AZ
AWS AZ
• Data is sent to S3 encrypted
• S3 encrypts data with key sent in request
• Data travels encrypted between AZs
• Data at rest is encrypted with customer-owned key
• Key remains in KMS
IAM
KMS
Object

18. S3 (client-side encryption)
AWS AZ
AWS AZ
AWS AZ
• Client encrypts the data locally with local held key
• Data is sent to S3 encrypted
• Data travels encrypted between AZs
• Data at rest is encrypted with customer-owned key
• AWS never sees the key

19. EBS (normal mode)
AWS AZ
AWS AZ
• Instance sends data to volume via hypervisor module
– Module can encrypt or not, depending on customer choice
– Data travels to the disks and between datacentres, potentially unencrypted
– Data lives unencrypted on Disk

20. EBS (server-side encryption)
AWS AZ
AWS AZ
• Instance sends encrypted data over hypervisor to volume
– Instance OS needs to support encryption
– Data travels encrypted to the disks and between datacentres
– Data lives encrypted on Disk
– AWS owns key/algorithm/data
– Included in scope of AWS SOC1 report
IAM
KMS
Volume

21. CloudHSM
• Tamper-Proof and Tamper-Evident
– Destroys its stored keys if under attack
• FIPS 140-2 Level 2 certified
• Base position is to be a Keystore
• Can also be used to timestamp documents
• You can send data for encrypt / decrypt
– Key never leaves the HSM as cleartext
– Can be used by several commercial software products
– Can be used by API to access the HSM
• Needs to be backed-up (ideally to HSM on customer premises)
• Can (and should) be combined in HA clusters
• Is NOT a key management system
– but can work with some third-party ones
• Communicates via:
– PKCS#11
– JCE
• Some applications need a “plugin”

22. Redshift can use CloudHSM
• When using CloudHSM
– Redshift gets cluster key from HSM
– Redshift generates a database key and encrypts it with the cluster key from the
CloudHSM
– Redshift encrypts and decrypts individual key for data blocks with the database
key
– Redshift supports re-encryption

23. RDS Crypto Support
• RDS / Oracle can use CloudHSM to store keys for Oracle Wallet
– So TDE can be HSM-backed
• RDS / MySQL, RDS / Postgres can use KMS to manage keys used
to encrypt underlying EBS volumes
– So all tables are encrypted at rest
• Note that in-memory database contents (once the database has
been unlocked) are cleartext
– RAM encryption is not something AWS has today, but it has been done in other
contexts

24. VPC VGW
• Hardware IPsec termination points
• Data on the VPC side of the VGW is unprotected by the VGW (no
re-encryption)
– If you need VPN termination with onward re-encryption, use EC2 instances with
OpenSWAN or Cisco CRSs instead…
• Uses pre-shared symmetric key
• The Key is a shared one between AWS and the customer
AWS AZ AWS AZCustomer

25. Between Regions
Region
Availability Zone
Availability Zone
Region
Availability Zone
Availability Zone
Public
Customer
WAN
DX Site DX Site
Customer
DC

26. Others
• Glacier
– Archives have always been encrypted – this is entirely transparent to the user
– Glacier keys are AES256
– AWS holds key/algorithm/data
• Route53
– Supports signed zones
• ELB
– Supports SSL termination including onward re-encryption and customer choice of
cipher suite (useful post-POODLE)
– AWS holds keys/algorithm/data
– Unidirectional trust only (no certificate-based authentication of client to server)
• Import/Export
– Currently relies on Truecrypt shared secret between customer and AWS for
exporting data
– Truecrypt has not been broken, but it is not longer maintained. Therefore
import/export will choose another option

27. Ronan Guilfoyle
Amazon Web Services Ireland
rguilfoy@amazon.com
Additional Resources:
http://aws.amazon.com/documentation
http://aws.amazon.com/compliance
http://aws.amazon.com/security