clevis

Clevis.go

clevis.go is a pure Golang implementation of clevis binding framework. The original C implementation can be found at https://github.com/latchset/clevis/

This project aims to be a pluggable library (rather than a set of tools) and functionally compatible with upstream.

This library in on par with the upstream implementation and supports following features:

• Network binding using Tang (so the data can be decrypted only when the tang server is available)
• TPM2 binding (the data can be decrypted when a specific TPM2 chip is accessed)
• Combining other bindings with Shamir's Secret Sharing

Using library

Here is an example of text decryption. First we want to encrypt (bind) a sample text. We use TPM2 binding here as an example:

$ clevis encrypt tpm2 '{}' <<< 'hello, world'
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..pDy_7V_YHq7gwh0G.Px-VUdv_dy2azz2Vvw.f-d7etmqrC3Xvdy8AoJa1w

The produced text is encrypted using a private key stored inside the TPM2 chip at your motherboard. Decryption is possible with this TPM chip only. Attempt to decrypt it on another computer will produce an error.

package main

import (
	"fmt"
	"github.com/anatol/clevis.go"
)

func main() {
	encrypted := `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..pDy_7V_YHq7gwh0G.Px-VUdv_dy2azz2Vvw.f-d7etmqrC3Xvdy8AoJa1w`
	plain, err := clevis.Decrypt([]byte(encrypted))
	if err != nil {
		panic(err)
	}

	fmt.Printf("decrypted text: %s", plain)
}

clevis.Decrypt takes the decrypted text and produces (unbinds) the original data.

Thanks

This project has been started as a part of Twitter HackWeek. Thank you Twitter and thank you Ian Brown for supporting open-source development.

License

See license file.