utils.go

package crypto

import (
	"crypto/rand"
	"encoding/base64"
	"fmt"

	"github.com/google/uuid"
)

// Key is a struct that holds a key as a byte array and as a base64 encoded
// string and the id of the key.
type Key struct {
	// ID is the id of the key
	ID uuid.UUID
	// Key as byte array
	Key []byte
	// Key as base64 encoded string
	KeyAsBase64 string
}

// KSAKey is a stuct that represents a the object delivered to a requesting instance.
type KSAKey struct {
	// KeyID is the id of the key.
	KeyID string `json:"key_ID"`
	// Key is the key value as Base64.
	Key string `json:"key"`
}

// Random256BitKey generates a random 256 bit key and returns it as a Key
// struct.
func Random256BitKey() (*Key, error) {
	// Create a new byte array with a length of 32 bytes
	b := make([]byte, 32)
	// fill the byte array with random bytes
	_, err := rand.Read(b)
	if err != nil {
		return nil, err
	}

	// Encode the byte array to a base64 encoded string
	keyAsBase64String := base64.StdEncoding.EncodeToString(b)

	return &Key{
		ID:          uuid.New(),
		Key:         b,
		KeyAsBase64: keyAsBase64String,
	}, nil
}

func GetCryptoAlgorithmByName(cryptoAlgorithmName string) (CryptoAlgorithm, error) {
	switch cryptoAlgorithmName {
	case "AES_256_GCM":
		return NewAES(cryptoAlgorithmName), nil
	case "OTP":
		return NewOTP(cryptoAlgorithmName), nil
	default:
		return nil, fmt.Errorf("The provided crypto algorithm name: %s is not supported.", cryptoAlgorithmName)
	}
}