©2015, Amazon Web Services, Inc. or its affiliates. All rights reserved

Crypto Options in AWS

Dave Walker – Specialist Solutions Architect, Security and ComplianceAmazon Web Services UK Ltd

28/01/16

The Cryptographic Trinity

Key

Algorithm

Data

…and Duality of Use• Encryption in transit

– Interesting in elastic / autoscaling environments• Encryption at rest

– Various solutions• …and when to do each

Encryption in Transit

Network Infrastructure

• “Do I need to encrypt data in transit inside my VPC(s)?”– It depends on your risk appetite…

• VPC is covered under PCI-DSS etc as a Layer 2 isolated network– “Are ne’er-do’wells with spades, Stanley knives, laptops and

photomultipliers a risk that you require mitigating, or are they residual risk that you accept?”

• Inter-AZ links, and inter-datacentre links within a Region, are not something we state as being encrypted on the wire

• …so you should assume they aren’t• However, there is likely to be other technology in place to get the most out of

WAN bandwidth, which may also serve as an obfuscation layer• …eg DWDM• …but what goes down that WAN pipe won’t be indistinguishable from whitenoise• …and therefore doesn’t pass an important strength test applied to Feistel ciphers

Anatomy of a Region

AWS DC AWS DC

AWS DC AWS DC

Availability Zone Availability Zone

Between Regions

Region

Availability Zone

Availability Zone

Region

Availability Zone

Availability Zone

“Public Internet”

Customer WAN

DX SiteDX Site

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 Marketplace appliances with VPN support– …or ensure that sensitive traffic is also encrypted at application level (ssh, https,

etc)• Uses pre-shared symmetric key (AES-256) - may change in future

AWS AZ AWS AZCustomer

Between Regions

Region

Availability Zone

Availability Zone

Region

Availability Zone

Availability Zone

Public

Customer WAN

DX Site DX Site

Customer DC

Encryption in Transit for Elastic Instances• No shortage of encryption options…

– ssh, etc• Key management and key propagation management

– More interesting!– “if newly-minted Instance A needs to talk to newly-minted Instance B and doesn’t have

its public ssh key…”– Kerberos realm auto-join at Instance create isn’t easy (addprinc needs passwords…)– Options with KMS to access encrypted sets of keys stored in S3 or DynamoDB…

• Enter “Directories of Secrets”• Some early third-party options to examine

– KeyWhiz: http://square.github.io/keywhiz/ – Vault: https://www.vaultproject.io/– Sneaker: https://github.com/codahale/sneaker– Lemur: https://github.com/Netflix/lemur

• Heavyweight option: Overlay networking (eg CohesiveFT VNS3)• Other parties working on further commercial options…

Encryption at Rest

AWS Key Management Service

• Designed for Scalability and Throughput• Uses bespoke AWS hardware + software• Is a multi-tenant service• Performs AES-256 operations• API for crypto command:

– Key Management• Activate, Deactivate, Create, Delete, Grant access,

Rotate– Encryption / Decryption

• Customer selects Master Key• Data Key is managed using envelope

encryption• All key access actions are logged in

CloudTrail

Customer MasterKey(s)

Data Key 1

Amazon S3 Object

Amazon EBS

Volume

Amazon Redshift Cluster

Data Key 2 Data Key 3 Data Key 4

CustomApplication

AWS KMS

AWS Key Management ServiceReference Architecture

Application or AWS Service

+Data Key Encrypted Data Key

EncryptedData

Master Key(s) in Customer’s Account

AWSKey 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.

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/*" ]}}

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• Data travels encrypted between AZs• Data at rest is encrypted with customer-owned key• Customer needs to send key in GET request

Customer needs to trust AWS to forget the key…

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" } } } ] }

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

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

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

EBS (server-side encryption)

AWS AZ

AWS AZ

• Instance sends encrypted data over hypervisor to volume– Instance OS needs to handle 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, PCI-DSS reports

IAM

KMS

Volume

CloudHSM• Tamper-Proof and Tamper-Evident

– Destroys its stored keys if under attack• FIPS 140-2 Level 2 certified• Essential function is “being a Keystore”• Can also be used to timestamp documents• You can send data for encrypt / decrypt• Needs to be backed-up (ideally to HSM on customer premises)• Can be (and should) be combined in HA clusters• Doesn’t do Financial Services specialised functions (eg PIN verify)• Is NOT a key management system

– but can work with some third-party ones• Communicates via:

– PKCS#11– JCE

• Some applications need a “plugin”– SafeNet supply one for Apache

CloudHSM Integration with S3, EBS, EC2• S3

– Integration using SafeNet KeySecure on EC2– White paper at

http://www2.safenet-inc.com/AWS-guides/SafeNetKMIP_AmazonS3_IntegrationGuide.pdf

• EBS and EC2– Use SafeNet KeySecure (6.1.2 or later) on EC2, backed by CloudHSM, for key

management– Install SafeNet ProtectV Manager on EC2 (c1.medium / m1.medium)– Install ProtectV Client on EC2 instances– Use ProtectV for EBS volume encryption (ext3, ext4, swap)– Supported platforms:

• RHEL 5.8, 6.2, 6.3• CentOS 6.2• Microsoft Windows 2008, 2012

– Encrypt full EBS-backed EC2 instances, including root volumes

Redshift can use CloudHSM, Without Additional Software• 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 data with the database key– Redshift supports re-encryption

RDS Crypto Support• RDS / Oracle EE can use CloudHSM to store keys for Oracle

keystore– …so TDE can be HSM-backed

• All RDS database types 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

Other Services• 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– DNSSEC is being looked-into

• 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 – be aware of

pentests reporting SSL renegotiation issues as per CVE-2009-3555)• Import/Export

– The pre-Snowball service relies on Truecrypt, with a shared secret between customer and AWS for exporting data

– Truecrypt has not been broken, but it is no longer maintained. Snowball uses AES-256, and keys are not stored on the device.

SafeNet Product Support for AWSSafeNet Product AWS Service(s) Supported Notes

ProtectV and Virtual KeySecure for AWS

EC2 or VPC Instances and EBS Storage

GovCloud (Beta)

• Requires Safenet KeySecure (HW or Virtual)• Available in AWS MarketPlace, as well as SafeNet sales channels

Virtual KeySecure for AWS CloudHSM • Available in AWS Marketplace• CloudHSM supports Virtual KeySecure as the hardware root of trust

for vKS master keys

StorageSecure AWS Storage Gateway • Safenet KeySecure Hardware (optional)• iSCSI integration (however StorageSecure also supports CIFS,

NFS, FTP, TFTP and HTTP protocols.)

Luna SA 7000 HSM CloudHSMRedShiftRDS (via 3rd party vendor)

• High availability• Key synchronization• Key Management

Luna Backup HSM CloudHSM • Key backup

ProtectApp S3 and EBS volumes • Can be integrated with Amazon S3 Encryption Clients and AWS SDKs (Java and .Net)

• Requires SafeNet KeySecure (HW or virtual)• Can be installed on an EC2/VPC instance to protect data stored on

EBS volumes.

ProtectFile EBS volumes and S3 • Requires SafeNet KeySecure (HD or Virtual)

Differences between CloudHSM and KMS

CloudHSM• Single-tenant HSM• Customer-managed durability and

availability• Customer managed root of trust• Generate or import keys• FIPS 140-2 Validation• Broad third-party app support• Symmetric and asymmetric ops• Fixed price ($16.5k/yr/hsm)• Broad range of symmetric and asymmetric

algorithms

KMS• Multi-tenant AWS service• Highly available and durable key

storage and management (including key rotation)

• AWS managed root of trust• Mint and use keys in situ• Extensive auditing• Broad support for AWS services• Symmetric encryption only• Usage-based pricing ($1/mo/key)• AES-256

Useful Reading

• Encrypting Data at Rest: https://d0.awsstatic.com/whitepapers/AWS_Securing_Data_at_Rest_with_Encryption.pdf

• AWS Key Management Service Cryptographic Details: https://d0.awsstatic.com/whitepapers/KMS-Cryptographic-Details.pdf

So:• Data in transit within an AZ might leave a given datacentre• Data in transit between AZs will leave a given datacentre• Data in transit between AWS Regions or between AWS and customer

premises needs to be taken care of, too– You can run VPNs over Direct Connect and via VPC VGWs, or ensure via firewalls

and proxies that only encrypted protocols pass between your premises and AWS• Data at Rest: baseline encryption question is turning into “why not?”• Key Management of Data at Rest: choices for key management and

control, with varying degrees of complexity• We have a great story for storage device decommissioning (US DoD

5220.22M)• Keys can also be deleted (new for KMS!)

Discussion Points• Hard encryption in transit might be excessive, in some contexts• 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 required for Compliance reasons

Get your data classification rightFind the balance between your obligations for

executive care, cost and complexity

©2015, Amazon Web Services, Inc. or its affiliates. All rights reserved

Dave Walker – Specialised Solutions Architect Security/ComplianceAmazon Web Services UK Ltd

28/01/16

Thank You