keyderivation

Documentation

Overview

Package keyderivation provides implementations of the keyset deriver primitive.

Example

package main

import (
	"fmt"
	"log"

	"github.com/tink-crypto/tink-go/v2/aead"
	"github.com/tink-crypto/tink-go/v2/keyderivation"
	"github.com/tink-crypto/tink-go/v2/keyset"
	"github.com/tink-crypto/tink-go/v2/prf"
)

func main() {
	template, err := keyderivation.CreatePRFBasedKeyTemplate(prf.HKDFSHA256PRFKeyTemplate(), aead.AES128GCMKeyTemplate())
	if err != nil {
		log.Fatal(err)
	}

	handle, err := keyset.NewHandle(template)
	if err != nil {
		log.Fatal(err)
	}

	deriver, err := keyderivation.New(handle)
	if err != nil {
		log.Fatal(err)
	}

	derivedHandle, err := deriver.DeriveKeyset([]byte("salt"))
	if err != nil {
		log.Fatal(err)
	}

	// Use the derived keyset.
	a, err := aead.New(derivedHandle)
	if err != nil {
		log.Fatal(err)
	}

	ciphertext, err := a.Encrypt([]byte("a secret message"), nil)
	if err != nil {
		log.Fatal(err)
	}

	plaintext, err := a.Decrypt(ciphertext, nil)
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(string(plaintext))
}

Output:

a secret message

Index

• func CreatePRFBasedKeyTemplate(prfKeyTemplate, derivedKeyTemplate *tinkpb.KeyTemplate) (*tinkpb.KeyTemplate, error)
• type KeysetDeriver
  • func New(handle *keyset.Handle) (KeysetDeriver, error)

Examples

• Package

Functions

func CreatePRFBasedKeyTemplate

func CreatePRFBasedKeyTemplate(prfKeyTemplate, derivedKeyTemplate *tinkpb.KeyTemplate) (*tinkpb.KeyTemplate, error)

CreatePRFBasedKeyTemplate creates a PRF-Based Deriver key template with the specified PRF and derived key templates. If either the PRF or derived key templates are not supported by the registry, an error is returned.

Types

type KeysetDeriver

type KeysetDeriver interface {
	DeriveKeyset(salt []byte) (*keyset.Handle, error)
}

KeysetDeriver is the interface used to derive new keysets based on an additional input, the salt.

The salt is used to create the keyset using a pseudorandom function. Implementations must be indistinguishable from ideal KeysetDerivers, which, for every salt, generates a new random keyset and caches it.

func New

func New(handle *keyset.Handle) (KeysetDeriver, error)

New generates a new instance of the Keyset Deriver primitive.