(sec301) strategies for protecting data using encryption in aws

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

Ken Beer

Principal Product Manager, AWS Cryptography Services

October 2015

SEC301

Strategies for Protecting Data

Using Encryption in AWS

What to expect from this session

• Understand your options for protecting your data with encryption

in AWS

• Understand how AWS Key Management Service (KMS) can

simplify encryption

• Understand alternatives such as AWS CloudHSM and partner

solutions

• Hear from Adobe Systems about their use of KMS

Plaintext

dataHardware/

software

Encrypted

data

Encrypted

data in storage

Encrypted

data key

Symmetric

data key

Master keySymmetric

data key

? Key hierarchy

?

Encryption primer

Where are keys stored?• Hardware you own?

• Hardware the cloud provider owns?

Where are keys used?• Client software you control?

• Server software the cloud provider controls?

Who can use the keys?• Users and applications that have permissions?

• Cloud provider applications you give permissions?

What assurances are there for proper security around keys?

“Key” questions to consider with any solution

Client-side encryption

• You encrypt your data before data submitted to service

• You supply encryption keys OR use keys in your AWS account

• Available clients:

• Amazon S3, Amazon EMR File System (EMRFS), Amazon DynamoDB

Server-side encryption

• AWS encrypts data on your behalf after data is received by service

• Integrated services: • S3, Amazon EBS, Amazon RDS, Amazon Redshift, Amazon WorkMail/WorkSpaces, AWS

CloudTrail, Amazon Simple Email Service, Amazon Elastic Transcoder, AWS Import/Export

Snowball, Amazon Kinesis Firehose

Options for using encryption in AWS

Your

applications

in your data

center

Your key

management

infrastructure in EC2

Your encryption

client application

Your key management

infrastructure Your application

in EC2

Your encrypted data in select AWS services

Client-side encryption in AWSS3/EMRFS and DynamoDB encryption clients in AWS SDKs

Amazon S3 Web

Server

HTTPS

Customer

Data

Amazon S3

Storage Fleet

Key is used at S3 web server, and then deleted.

Customer must provide same key when

downloading to allow S3 to decrypt data.

Customer-

provided key

Server-side encryption in AWSS3 server-side encryption with customer-provided encryption keys (SSE-C)

Plaintext

DataEncrypted

Data

Customer-

provided key

Server-side encryption in AWSS3 (SSE-KMS)

AWS Key Management Service (KMS)

• Managed service that simplifies creation, control, rotation, and use

of encryption keys in your applications

• Integrated with AWS server-side encryption

• S3, EBS, RDS, Amazon Aurora, Amazon Redshift, WorkMail,

Amazon WorkSpaces, CloudTrail, and Amazon Elastic Transcoder

• Integrated with AWS client-side encryption

• AWS SDKs, S3 encryption client, EMRFS client, and DynamoDB

encryption client

• Integrated with CloudTrail to provide auditable logs of key usage for

regulatory and compliance activities

• Available in all commercial regions except China

AWS KMSIntegrated with AWS Identity and Access Management (IAM) console

How clients and AWS services typically integrate with KMS

Two-tiered key hierarchy using envelope

encryption

• Unique data key encrypts customer data

• KMS master keys encrypt data keys

Benefits

• Limits risk of compromised data key

• Better performance for encrypting large

data

• Easier to manage small number of

master keys than millions of data keys

• Centralized access and audit of key

activity

Customer master

keys

Data key 1

S3 object EBS

volume

Amazon

Redshift

cluster

Data key 2 Data key 3 Data key 4

Custom

application

KMS

Your application or

AWS service

+

Data key Encrypted data key

Encrypted

data

Master keys in

customer’s account

KMS

How AWS services use your KMS keys

1. Client calls kms:GenerateDataKey by passing the ID of the KMS master key in your

account.

2. Client request is authenticated based on permissions set on both the user and the key.

3. A unique data encryption key is created and encrypted under the KMS master key.

4. The plaintext and encrypted data key is returned to the client.

5. The plaintext data key is used to encrypt data and is then deleted when practical.

6. The encrypted data key is stored; it’s sent back to KMS when needed for data decryption.

create-volume [--dry-run | --no-dry-run] [--size <value>] [--snapshot-id

<value>] --availability-zone <value> [--volume-type <value>] [--iops <value>]

[--encrypted | --no-encrypted] [--kms-key-id <value>] [--cli-input-json <value>]

[--generate-cli-skeleton]

Console

AWS CLI/SDK

Interfaces to select KMS keys in AWS services

You control how and when your KMS keys can

be used and by whom

Sample permissions on a key:

• Can only be used for encryption and decryption by <these users and

roles> in <this account>

• Can only be used by application A to encrypt data, but only used by

application B to decrypt data

• Can only be used to decrypt data if the service resource is active and

additional parameters about the resource are passed in the call

• Can be managed only by this set of administrator users or roles

Fully integrated with AWS Identity and Access Management

Rotating keys in KMS

What key rotation means:

• A new version of a master key is created, but mapped to the same

key ID or alias

• All new encryption requests use the new version

• All previous versions of keys are kept to perform decryption on

older ciphertexts

There is nothing users/applications need to do after a rotation –

the same keyID or alias just works

AWS CLI

enable-key-rotation --key-id <value>

Console (Key Summary Page)

Auditability of KMS key usage through

AWS CloudTrail

"EventName":"DecryptResult", This KMS API was called…

"EventTiime":"2014-08-18T18:13:07Z", ….at this time

"RequestParameters":

"{\"keyId\":\"2b42x363-1911-4e3a-8321-6b67329025ex”}”, …in reference to this key

“EncryptionContext":"volumeid-12345", …to protect this AWS resource

"SourceIPAddress":"42.23.141.114 ", …from this IP address

"UserIdentity":

“{\"arn\":\"arn:aws:iam::957737256530:user/User123“} …by this AWS user in this account

KMS APIs to build your own applications

Example management APIs

• CreateKey, CreateAlias

• DisableKey

• EnableKeyRotation

• PutKeyPolicy

• ListKeys, DescribeKey

Example data APIs

• Encrypt

• Decrypt

• ReEncrypt

• GenerateDataKey

26 APIs and growing

http://docs.aws.amazon.com/kms/latest/APIReference/Welcome.html

http://docs.aws.amazon.com/kms/latest/APIReference/Welcome.html

KMS assurancesWhy should you trust AWS with your keys?

• There are no tools in place to access your physical key material.

• Your plaintext keys are never stored in nonvolatile memory.

• You control who has permissions to use your keys.

• Separation of duties between systems that use master keys and

ones that use data keys.

• Multiparty controls for all maintenance of KMS systems that use

your master keys.

• Third-party evidence of these controls:

• Service Organization Control (SOC 1)

• PCI-DSS

• See AWS Compliance packages for details

Pricing for KMS

$1/key version/month

$0.03 per 10,000 API requests

• 20,000 free requests per month

Alternatives to KMSIn order to have different controls over the security of your keys

1. AWS CloudHSM

2. AWS Partner Solutions

3. Do it yourself

AWS CloudHSM

• You receive dedicated access to HSM

appliances

• HSMs located in AWS data centers

• Managed and monitored by AWS

• Only you have access to your keys and

operations on the keys

• HSMs are inside your Amazon VPC –

isolated from the rest of the network

• Uses SafeNet Luna SA HSM appliances

CloudHSM

AWS administrator –

Manages the appliance

You – Control keys and

crypto operations

Amazon Virtual Private Cloud

AWS CloudHSM

Available in seven regions worldwide

• US East (N. Virginia), US West (Oregon), EU (Ireland), EU (Frankfurt) and Asia Pacific (Sydney, Tokyo, Singapore)

Compliance

• Included in AWS PCI DSS and SOC-1 compliance packages

• FIPS 140-2 level 2 (maintained by Gemalto/SafeNet)

Typical use cases

• Use with Redshift, RDS for Oracle

• Integrate with third-party software (Oracle, SQL Server, Apache, SafeNet)

• Build your own custom applications

SafeNet ProtectV manager

and Virtual KeySecure

in EC2

EBS volume encryption with CloudHSM and

SafeNet Software

SafeNet ProtectV with Virtual KeySecure

CloudHSM stores the master key

SafeNet

ProtectV

client

CloudHSM

Your encrypted data

in EBS

Your applications

in EC2

ProtectV client

• Encrypts I/O from

EC2 instances to EBS

volumes

• Includes preboot

authentication

Pricing for CloudHSM

HSM provisioned in any region has a $5,000 one-time charge

Starting at $1.88/hour metered charge after setup• Hourly rate varies by region

As low as $21,500 in year one; $16,500 in subsequent years

Requests not billed; limited only by the device capacity• Varies depending on algorithm and key size

Comparing CloudHSM with KMS

CloudHSM

• Dedicated access to one or more HSM

devices that complies with government

standards (e.g., FIPS 140-2, Common

Criteria)

• You control all access to your keys and

the application software that uses them

• Supported applications: • Your custom software

• Third-party software

• AWS services: Redshift, RDS for Oracle

KMS

• Highly available and durable key storage,

management, and auditable service

• Easily encrypt your data across AWS

services and within your own applications

based on policies you define

• Supported applications:• Your custom software built with AWS SDKs/CLI

• AWS services (S3, EBS, RDS, Aurora, Redshift,

WorkMail, WorkSpaces, CloudTrail, Elastic

Transcoder)

Partner solutions in AWS Marketplace

• Browse, test, and buy encryption and key management solutions

• Pay-by-the-hour, monthly, or annual

• Software fees added to AWS bill

• Bring Your Own License

Your encryption

client application

Your key management

infrastructure

Your

applications

in your data

center

Your application

in EC2

Your key

management

infrastructure in EC2

Your encrypted data in AWS services

…

DIY key management in AWSEncrypt data client-side and send ciphertext to AWS storage services

KMS AWS CloudHSMAWS Marketplace

Partner SolutionsDIY

Where keys are

generated and stored

AWS In AWS, on an HSM

that you control

Your network or in

AWS

Your network or in

AWS

Where keys are used AWS services or your

applications

AWS or your

applications

Your network or your

EC2 instance


EC2 instance

How to control key use Policy you define;

enforced by AWS

Customer code +

SafeNet APIs

Vendor-specific

management

Config files, vendor-

specific management

Responsibility for

performance/scale

AWS You You You

Integration with AWS

services?

Yes Limited Limited Limited

Pricing model Per key/usage Per hour Per hour/per year Variable

Comparison of key management options

KMS CloudHSMAWS Marketplace


Where keys are



that you control

Your network or in

AWS

Your network or in

AWS


applications

AWS or your

applications


EC2 instance


EC2 instance


enforced by AWS

Customer code +

SafeNet APIs

Vendor-specific

management


specific management

Responsibility for

performance/scale

AWS You You You


services?




Customer success story

Frank Wiebe – Principal Scientist, Adobe Systems

Adobe use case

• Mobile app built using the CreativeSDK makes API

requests to purchase billable content

• Mobile application generates an HMAC signature

using a secret associated with app’s API key

• The HMAC signature is used to validate the

identity of the mobile app that will be connecting

• This approach is used to securely identify the

mobile app to avoid fraudulent charges against a

customer’s account

Adobe

KMS

AWS KMS

Adobe use case (cont’d)

• API Gateway needed the capability to retrieve and securely store the secret

associated with the API key in a cache.

• We wanted to minimize the time plaintext sensitive data remained in cache and

avoid storing the sensitive data on disk.

• Using the combination of AWS KMS and Amazon ElastiCache for Redis met

our requirements.

• This approach was used to securely store the API key’s secret used to

validate the digital signature of an API request processed by the adobe.io

API Gateway.

Adobe requirements

• Symmetric encryption

• We needed a secure method for sharing a secret that could be used by both the

mobile app and the API Gateway to validate an HMAC signature.

• High availability and durability with low management overhead and cost

• As a DevOps focused on API management, we did not have the time or the staff

to build and deploy our own key management solution that would meet with the

approval of Adobe Security.

• Audit trail of and strong controls to manage use of encryption keys

• We needed to control which EC2 instances could access keys.

• Log the storage and retrieval of keys.

• Fast deployment

• Following the acquisition of Aviary by Adobe, we had less than 2 months to

design, build, and deploy an approved solution to support the integration of the

Aviary APIs within the CreativeSDK.

How AWS KMS meets Adobe requirements

• Symmetric encryption

• 256-bit AES-GCM for KMS master key

• High availability and durability

• Consistent with our experience of AWS as a whole

• Audit trail of and strong controls to manage use of encryption keys

• Integration with IAM policies

• Ability to separate permission to encrypt from permission to decrypt using IAM roles for EC2

to acquire temporary security credentials to access KMS for 24 hours

• CloudTrail shows us all use of KMS master keys

• Fast deployment

• Solution was designed, built, tested, and approved by Adobe Security within 4 weeks

1. Client makes an API request to Adobe.io with API key and an

object signed using the API key secret (“digital signature”).

2. API Gateway validates digital signature. How this works:

• If the secret for validation is not in the NGINX shared cache, retrieve

the secret (in plaintext) from the Adobe key management API and

encrypt by sending to AWS KMS.

• API Gateway calls AWS KMS to generate a data encryption key (DEK)

for the secret using the GenerateDataKey API.

• Encrypt the secret with the DEK using an AES-256 CBC SHA512

algorithm, and store the ciphertext blob versions of the DEK and secret in

the shared cache with a TTL.

• If secret for validation is in the NGINX shared cache, API Gateway

makes a request to AWS KMS using the Decrypt API to retrieve the

DEK (in plaintext form), which is then used to decrypt the ciphertext

blob containing the secret.

Adobe

KMS

AWS KMS

API request flow

NGINX – AWS SDK – Setup

function _M:new(o)

local o = o or {}

setmetatable(o, self)

self.__index = self

if not o.___super then

printInitObject(o)

self:throwIfInitParamsInvalid(o)

self.kmsService = KmsService:new({

aws_region = o.aws_region,

aws_secret_key = o.aws_secret_key, – Optional. The code will automatically look for an IAM user.

aws_access_key = o.aws_access_key, – Optional. The code will automatically look for an IAM user.

aws_iam_user = o.aws_iam_user, – Optional. But it's more performant to provide it.

security_credentials_host = o.security_credentials_host,

security_credentials_port = o.security_credentials_port,

aws_debug = o.aws_debug, – Print warn level messages on the nginx logs.

aws_conn_keepalive = o.aws_conn_keepalive, – How long to keep the sockets used for AWS alive.

aws_conn_pool = o.aws_conn_pool, – The connection pool size for sockets used to connect to AWS.

shared_cache_dict = o.shared_cache_dict – Shared dict to keep IAM credentials cached for performance improvements.

})

end

return o

end

Adobe has implemented an AWS SDK for NGINX that has

been open sourced. This is the configuration of AWS KMS

within the SDK.

This SDK is available at https://github.com/adobe-

apiplatform/api-gateway-aws

NGINX – Secret Reader integrated with AWS KMS-- Encrypts the plain_text returning a pair of ( cipher_text, seed_cipher ). Use this pair to call

the decrypt method.

-- @param plain_text The Text to encode

--

function _M:encrypt(plain_text)

local DEK_plain_text – the DEK plain text

local seed_cipher – in the DEK cipher text blob

local cipher, status, body = self.kmsService:generateDataKey(self.aws_key_id, "AES_256")

if (cipher == nil) then

ngx.log(ngx.WARN, "Could not GenerateDataKey. AWS Status:", tostring(status), ", Body:",

tostring(body))

return nil, nil

end

seed_cipher = cipher.CiphertextBlob

DEK_plain_text = cipher.Plaintext -- this is the plaintext of the DEK

local cipher_text = self:encryptText(plain_text, DEK_plain_text) -- encrypt API Key secret

return cipher_text, seed_cipher -- return the encrypt API Key secret & ciphertext blob

End

+

function _M:encryptText(plain_text, seed_text)

local aes_256_cbc_sha512x5 = aes:new(seed_text,

”—insert—your—salt—here--",

aes.cipher(256, "cbc"),

aes.hash.sha512, 5)

local encrypted =

aes_256_cbc_sha512x5:encrypt(plain_text)

return encrypted

end

The SDK generates a data encryption key

(DEK), and then uses the DEK to

encrypt/decrypt data locally using the encryptText function (at right).

Operational experience post-deployment

• No operational or performance-related issues since it

was launched

• 100% availability over the past 10 months

• After initial design discussion with AWS Solutions

Architect and KMS Product Manager, we haven’t opened

an AWS Support case for this application

Wish list for KMS

Cross-region replication of encrypted AWS resources

• Can’t move KMS master keys between regions, but the process of

re-encrypting data between regions could be easier

Resources

KMS

• https://aws.amazon.com/kms

Whitepaper on KMS cryptographic details

• https://d0.awsstatic.com/whitepapers/KMS-Cryptographic-Details.pdf

CloudHSM

• https://aws.amazon.com/cloudhsm/

Whitepaper on data-at-rest encryption and key management in AWS

• https://aws.amazon.com/whitepapers/

S3 encryption client

• http://aws.amazon.com/articles/2850096021478074

AWS Partner Network

• http://www.aws-partner-directory.com/

AWS Security Blog

• http://blogs.aws.amazon.com/security

https://aws.amazon.com/kms

https://d0.awsstatic.com/whitepapers/KMS-Cryptographic-Details.pdf

https://aws.amazon.com/cloudhsm/

https://aws.amazon.com/whitepapers/

http://aws.amazon.com/articles/2850096021478074

http://www.aws-partner-directory.com/

http://blogs.aws.amazon.com/security

Related Sessions

• SEC401: Encryption Key Storage at Okta

• Pallazzo K at 4:15 P.M. today

• STG402: Amazon EBS Deep Dive

• BDT314: Running a Big Data and Analytics Application

on Amazon EMR and Amazon Redshift with a Focus on

Security

Remember to complete

your evaluations!

Thank you!

(sec301) strategies for protecting data using encryption in aws

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