I am developing a project which requires video file encryption. I am familiar with AWS S3 so I have decided to use the same. I found the link Reference Link
Which says we need to provide our encryption key to to encrypt the data and AWS takes care of the data writing and we can access the file again by passing the same encryption key.
I want to know from where should I generate the encryption key?
You're looking at the "customer-provided encryption keys" section. In that case, you provide the encryption key.
If you don't want to, or know how to, manage your own keys, you should use S3-managed encryption keys or (even better) KMS-managed encryption keys.
For even more safety, client-side encryption is nice.
Related
My understanding is that by generating your own key and use that to encrypt stuff, it prevents a cloud provider from being able to read your data at rest. But before a cloud provider can use this customer managed key to encrypt/decrypt, it has to first have access to the key's plaintext. What stops a cloud provider from actually storing that plaintext and still has access to my data at rest?
Different cloud provider might have different approach to this, so I'm using AWS S3 as a reference here, which requires you to send the key in the request. https://docs.aws.amazon.com/AmazonS3/latest/userguide/ServerSideEncryptionCustomerKeys.html
In the SSE-C scenario you refer to, the user provides AWS the plaintext data and plaintext key (over https) and then AWS performs the encryption and discards the key. The benefit to the user is that the user does not have to perform cryptographic operations.
If there is a concern about AWS having access to plaintext data or keys, the user can encrypt the data on the client computer and then send the data to AWS already encrypted. This is the client-side encryption scenario.
I have recently been reading about Amazon KMS, including envelope encryption. The source I used for envelope encryption (Free Code Camp) seems to consider 4 levels of envelope encryption (data encryption key, key encryption key, KMS master key and root KMS master key), as shown in the figure below:
On the other hand, what I have read in aws only seems to consider two levels (KMS key or key encryption key and data encryption key), as shown in the figure below:
Am I missing something here? Is this disparity only apparent?
Thanks in advance for your answers!
What you see here are just different levels of abstraction.
The upper diagram shows the whole chain of keys involved in creating data keys for encryption/decryption. It peeks under the hood of the KeyId abstraction.
The docs are quite extensive as cryptography is famously littered with pitfalls and edge cases, but here's my not entirely accurate but useful enough mental model of the process:
Through heavily-audited and secure random magic hardware appliances (HSMs) can come up with keys that (almost, except for replication) never leave the appliance. Besides creating these keys, HSMs can also encrypt and decrypt data using these keys as well as create more keys.
KMS exposes these HSMs in some ways to you. It allows you to manage these keys through the KMS API and create an abstraction called a master Key (there are different versions...) identified by a KeyId. This master key is not necessarily a single key (key material is what AWS uses in the docs).
Rather there are multiple keys under the hood, but they are not directly exposed to the user. The underlying keys can be rotated according to a schedule. Effectively this key is versioned, but only the most recent version is used to encrypt new data; older versions are only used to decrypt data.
The other keys in the chain in the diagram are pretty much just implementation details that you don't need to know unless you plan to audit KMS in which case my mental model won't be enough. In practice, the lower diagram is much more important.
The lower diagram shows what KMS looks like from a client that uses KMS to manage encryption keys to encrypt data in another system. To use KMS in a system, you only need to know the identifier of a KMS Key (KeyId) and have the appropriate permissions.
The flow looks like this for encryption:
You make a GenerateDataKey API Call to KMS and pass in the KeyId of the key you wish to use. KMS will then return (among other things) a plain text data key and an encrypted data key.
You use the plain text data key to encrypt your data locally and store the encrypted data alongside the encrypted data key. Next, you delete the plain text data key from memory.
For decryption the flow is as follows:
You read the encrypted data key from the encrypted object and make a call to the Decrypt API passing in the encrypted data key. Assuming you have permission, KMS will return the plain text data key [1][2].
You use the plain text data key to decrypt your encrypted data.
From the client's perspective, all you need to know about the keys that KMS uses is the KeyId (by default, there are more advanced features like encryption contexts).
[1] for symmetric encryption, it can infer the correct KeyId from the metadata, but as a best practice, you should send the KeyId as well.
[2] AWS infers the correct key-material for decryption from metadata in the encrypted blob.
I am storing data in file in aws s3 and already enabled SSE. but i am curious to know is there a way to encrypt the data so when someone download the file so they cant see the content?? I am just new to AWS and it would be great if somw one give the input
Use the AWS Key Management Service (AWS KMS) to encrypt the data prior to uploading it to an Amazon S3 bucket. Then the data will remain encrypted until it's decrypted using the key. YOu can find an example here (for Java SDK)
https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/javav2/example_code/s3/src/main/java/com/example/s3/KMSEncryptionExample.java
already enabled SSE.
SSE encrypts the content on S3, but an authenticated client cloud access the content in plain, the encryption is done under the hood and the client is unable to access the ciphertext (encrypted form)
You can use the default s3 key or a custom KMS key (CMS) , where the client need explicit access to decrypt the content.
download the file so they cant see the content??
Then the content needs to be encrypted before the upload. AWS provides some support for the client-side encryption but the client is free to implement its own encryption strategy and the key management.
To solve trouble with managing the keys on the client side, it's often more practical to stick with SSE and allow access to S3 or the used CMS (key) only to identities that must access the content.
I am expecting very high traffic on one of my services, and I would like to add encryption for a new feature. I know KMS makes an API call each encrypt/decrypt call, but is it possible to use KMS for key management and cache the keys in memory to encrypt/decrypt locally without additional API calls?
The KMS key never leaves its hardware. That's it.
By default the KMS is intended for the envelope encryption. There is a data encryption key and KMS is used to encrypt the data key.
You can call the KMS to generate a random data key along the its encrypted value and then use the data-key to encrypt the data itself.
If you are encrypting for the same system (data are encrypted for the same target ), you may reuse the same data key and use a unique IV to encrypt multiple messages.
Edit: I'd suggest using the AWS Encryption SDK a bit helping the developers to do it properly
Is it possible to get files from encrypted S3 buckets using boto 2? I am working with a project that uses S3 in several places and has to read/write to an encrypted S3 bucket. I would like to make as small a change as possible, for the time being, to support encryption.
Encryption actually works at the object level, rather than the bucket.
There are several ways to use encryption. If it is Protecting Data Using Server-Side Encryption with Amazon S3-Managed Encryption Keys (SSE-S3), then as long as your app has permission to access the object then it will be automatically decrypted. (The app won't even notice that it was encrypted!)
If it is Protecting Data Using Server-Side Encryption with AWS KMS–Managed Keys (SSE-KMS), the app will also need adequate permissions to use the key in KMS. The object will be automatically decrypted, but it needs permissions to use the key.
If the app is Protecting Data Using Server-Side Encryption with Customer-Provided Encryption Keys (SSE-C), then the app must provide the encryption key when it tries to access the object.
And finally, if it is Protecting Data Using Client-Side Encryption, then the app is totally responsible for encryption/decryption.
It is most likely that your data is using Server-Side Encryption with Amazon S3-Managed Encryption Keys (SSE-S3). If so, then your app doesn't have to do anything — it will all be handled automagically by Amazon S3.