kmsencrypt

A tool designed to do KMS based envelope encryption of files.

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Decryption

1. takes a file {filename.kms} that you have encrypted with this program
2. base64 decodes the file and extracts the IV and encryption key from the prefix
3. decrypts the encryption key with the proper EncryptionContext using KMS
4. then takes that key and unencrypts the data
5. saves the data in a local file of the name {filename}

Encryption

1. This takes the file {filename},
2. generates a KMS encryption key tied to a supplied EncryptionContext value and KMS Customer Master Key
3. encrypts the file with the encryption key
4. prepends the encrypted key and IV on to the file
5. base64 encodes the new file
6. saves it as {filename.kms}

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How to build:

git clone into the $GOPATH/src/github.com/DonMills directory

mkdir $GOPATH/src/github.com/DonMills
cd $GOPATH/src/github.com/DonMills
git clone https://github.com/DonMills/kmsencrypt.git

or

go get github.com/DonMills/kmsencrypt

This tool requires the "aws-sdk-go" and the "urfave/cli" packages be installed.

go get github.com/aws/aws-sdk-go/
go get github.com/urfave/cli

Alternatively, if you have glide installed, you can just get the deps like this:

glide up

Then just build or install it...

go install

or

go build -o kmsencrypt
./kmsencrypt 

Usage Notes

The tool has a full help system, but in general usage is

 kmsencrypt [command] {command specific options}

where commands are

kmsencrypt encrypt [localfilename] [context]
OPTIONS:
   -c value  The customer master key id - can set with KMSENCRYPT_CMKID environment variable [$KMSENCRYPT_CMKID]

or

kmsencrypt decrypt [localfilename] [context]

Dealing with an "AWS Error: NoCredentialProviders" error or needing ~/.aws/config

In some situations (like needing a STS token to work on an environment) or if you have entries in your ~/.aws/config file that are needed, you may need to set the following environment variable:

AWS_SDK_LOAD_CONFIG=1

This is a function of the aws sdk for go discussed here: http://docs.aws.amazon.com/sdk-for-go/api/aws/session/

Mac installation via homebrew

New! Now you can install on a mac by using homebrew.

brew install DonMills/tools/kmsencrypt