signature.go

Documentation: edge-infra.dev/pkg/edge/datasync/internal/signature

     1  package signature
     2  
     3  import (
     4  	"crypto/hmac"
     5  	"crypto/sha512"
     6  	"encoding/hex"
     7  	"errors"
     8  	"strings"
     9  	"time"
    10  
    11  	"edge-infra.dev/pkg/edge/datasync/internal/config"
    12  )
    13  
    14  type MessageSignatureContext struct {
    15  	MessageID   string
    16  	MessageType string
    17  	Payload     []byte
    18  	Timestamp   time.Time
    19  }
    20  
    21  func Generate(sharedKey string, secretKey string, messageContext MessageSignatureContext, organizationName string) (string, error) {
    22  	if sharedKey == "" || secretKey == "" {
    23  		return "", errors.New("failed to sign message. missing keys")
    24  	}
    25  
    26  	signableContent := getSignableContent(messageContext, organizationName)
    27  	// if err != nil {
    28  	// 	return "", fmt.Errorf("failed to sign content. %v", err.Error())
    29  	// }
    30  
    31  	authenticationHash := GenerateHmac(secretKey, signableContent, messageContext.Timestamp)
    32  
    33  	return sharedKey + ":" + authenticationHash, nil
    34  }
    35  
    36  func getSignableContent(messageContext MessageSignatureContext, organizationName string) string {
    37  	appKey := config.GetAppKey()
    38  
    39  	values := make([]string, 0)
    40  
    41  	// h := md5.New()
    42  	// _, err := io.WriteString(h, string(messageContext.Payload))
    43  	// if err != nil {
    44  	// 	return "", fmt.Errorf("failed to write payload with md5. %v", err.Error())
    45  	// }
    46  
    47  	// md5Checksum := h.Sum(nil)
    48  
    49  	values = append(values, appKey)
    50  	// values = append(values, string(md5Checksum))
    51  	values = append(values, string(messageContext.Payload)) // TODO: maybe dont
    52  	values = append(values, messageContext.MessageID)
    53  	values = append(values, organizationName)
    54  
    55  	valuesWithContent := make([]string, 0)
    56  	for _, value := range values {
    57  		if value != "" {
    58  			valuesWithContent = append(valuesWithContent, value)
    59  		}
    60  	}
    61  
    62  	signableContent := strings.Join(valuesWithContent, "\n")
    63  	//fmt.Println(signableContent)
    64  	return signableContent
    65  }
    66  
    67  func GenerateHmac(secretKey string, signableContent string, timestamp time.Time) string {
    68  	iso8601Timestamp := timestamp.Format(time.RFC3339)
    69  
    70  	uniqueKey := secretKey + iso8601Timestamp
    71  
    72  	// Create a new HMAC by defining the hash type and the key (as byte array)
    73  	h := hmac.New(sha512.New, []byte(uniqueKey))
    74  	// Write Data to it
    75  	_, err := h.Write([]byte(signableContent))
    76  	if err != nil {
    77  		return ""
    78  	}
    79  	// Get result and encode as hexadecimal string
    80  	sha := hex.EncodeToString(h.Sum(nil))
    81  
    82  	return sha
    83  }
    84
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