Performing cryptographic operations with the GREP11 API

Example: Generating random data using the GenerateRandomRequest() function

GREP11 API supports programming languages with gRPC libraries. Two sample GitHub repositories are provided for you to test the GREP11 API:

• The sample GitHub repository for Golang
• The sample GitHub repository for JavaScript

You can use the following Golang code example to generate random data by calling the GenerateRandom function.

This example assumes that extra required Golang packages are included through import statements, such as the gRPC and http packages. The import pb "github.com/IBM-Cloud/hpcs-grep11-go/grpc" statement is used by GREP11 to perform API function calls.

import pb "github.com/IBM-Cloud/hpcs-grep11-go/grpc"

// Data structure and supporting methods used for GREP11 authentication
// IAMPerRPCCredentials type defines the fields required for IBM Cloud IAM authentication
// This type implements the gRPC PerRPCCredentials interface

type IAMPerRPCCredentials struct {
	expiration  time.Time
	updateLock  sync.Mutex
	AccessToken string // Required if APIKey nor Endpoint are specified - IBM Cloud IAM access token
	APIKey      string // Required if AccessToken is not specified - IBM Cloud API key
	Endpoint    string // Required if AccessToken is not specified - IBM Cloud IAM endpoint
}

// GetRequestMetadata is used by GRPC for authentication
func (cr *IAMPerRPCCredentials) GetRequestMetadata(ctx context.Context, uri ...string) (map[string]string, error) {
	// Set token if empty or Set token if expired
	if len(cr.APIKey) != 0 && len(cr.Endpoint) != 0 && time.Now().After(cr.expiration) {
		if err := cr.getToken(ctx); err != nil {
			return nil, err
		}
	}

	return map[string]string{
		"authorization":    cr.AccessToken,
	}, nil
}

// RequireTransportSecurity is used by gRPC for authentication
func (cr *IAMPerRPCCredentials) RequireTransportSecurity() bool {
	return true
}

// getToken obtains a bearer token and the expiration
func (cr *IAMPerRPCCredentials) getToken(ctx context.Context) (err error) {
	cr.updateLock.Lock()
	defer cr.updateLock.Unlock()

	// Check if another thread has updated the token
	if time.Now().Before(cr.expiration) {
		return nil
	}

	var req *http.Request
	client := http.Client{}
	requestBody := []byte("grant_type=urn:ibm:params:oauth:grant-type:apikey&apikey=" + cr.APIKey)

	req, err = http.NewRequest("POST", cr.Endpoint+"/identity/token", bytes.NewBuffer(requestBody))
	if err != nil {
		return err
	}

	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req = req.WithContext(ctx)
	resp, err := client.Do(req)
	if err != nil {
		return err
	}

	respBody, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("failed to read response body: %s", err)
	}
	defer resp.Body.Close()

	iamToken := struct {
		AccessToken string `json:"access_token"`
		ExpiresIn   int32  `json:"expires_in"`
	}{}

	err = json.Unmarshal(respBody, &iamToken)
	if err != nil {
		return fmt.Errorf("error unmarshaling response body: %s", err)
	}

	cr.AccessToken = fmt.Sprintf("Bearer %s", iamToken.AccessToken)
	cr.expiration = time.Now().Add((time.Duration(iamToken.ExpiresIn - 60)) * time.Second)

	return nil
}

// Generating a GREP11 API function call

// The following IBM Cloud items need to be changed prior to running the sample program
const address = "<grep11_server_address>"

var callOpts = []grpc.DialOption{
  grpc.WithTransportCredentials(credentials.NewTLS(&tls.Config{})),
  grpc.WithPerRPCCredentials(&util.IAMPerRPCCredentials{
    APIKey:   "<ibm_cloud_apikey>",
    Endpoint: "https://iam.cloud.ibm.com",
  }),
}

conn, err := grpc.Dial(address, callOpts...)
if err != nil {
		panic(fmt.Errorf("Could not connect to server: %s", err))
}
defer conn.Close()

cryptoClient := pb.NewCryptoClient(conn)

rngTemplate := &pb.GenerateRandomRequest{
		Len: (uint64)(ep11.AES_BLOCK_SIZE),
}

// Generate 16 bytes of random data for the initialization vector
rng, err := cryptoClient.GenerateRandom(context.Background(), rngTemplate)
if err != nil {
		panic(fmt.Errorf("GenerateRandom Error: %s", err))
}
iv := rng.Rnd[:ep11.AES_BLOCK_SIZE]
fmt.Println("Generated IV")

In the example, update the following variables:

• Replace <grep11_server_address> with the value of your GREP11 API endpoint. To find the service endpoint URL, from your provisioned service instance UI, click Overview > Connect > Enterprise PKCS #11 endpoint URL. Alternatively, you can dynamically retrieve the API endpoint URL. The returned value includes the following. Depending on whether you are using public or private network, use the public or private service endpoint value that is returned in the ep11 section.

  {
    "instance_id": "<instance_ID>",
    "kms": {
      "public": "<instance_ID>.api.<region>.hs-crypto.appdomain.cloud",
      "private":"<instance_ID>.api.private.<region>.hs-crypto.appdomain.cloud"
    },
    "ep11": {
      "public": "<instance_ID>.ep11.<region>.hs-crypto.appdomain.cloud",
      "private":"<instance_ID>.ep11.private.<region>.hs-crypto.appdomain.cloud"
    }
  }
  

  If you create your instances after April 12 2024 in certain regions, you might need to use the new API endpoints with the new format as <instance_ID>.ep11.<REGION>.hs-crypto.appdomain.cloud. The availability date varies by region. For more information about the supported regions, the availability dates, and the new endpoint URLs, see New endpoints.

• Replace <ibm_cloud_apikey> with the service ID API key that you created. The service ID API Key can be created by following the instruction in Managing service ID API key.

If the sample request is processed successfully, random data with a length of 16 bytes will be returned, as specified in ep11.AES_BLOCKSIZE.

The previous authentication example as well as more Golang code examples can be found at:

• GREP11 API examples
• IBM Cloud IAM support for GREP11