feat: b64 content hash and hmac sign

b64/hmac.go

@@ -0,0 +1,42 @@
+package b64
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+)
+
+// ContentHash computes the base64 encoded SHA-256 hash of the given content.
+func ContentHash(content []byte) (string, error) {
+	sha256 := sha256.New()
+
+	_, err := sha256.Write(content)
+	if err != nil {
+		return "", err
+	}
+
+	hb := sha256.Sum(nil)
+	s := base64.StdEncoding.EncodeToString(hb)
+
+	return s, nil
+}
+
+// Hmac256 computes the base64 encoded HMAC-SHA-256 hash of the given message using the given secret.
+func Hmac256(message, secret string) (string, error) {
+	decodedSecret, err := base64.StdEncoding.DecodeString(secret)
+	if err != nil {
+		return "", err
+	}
+
+	hash := hmac.New(sha256.New, decodedSecret)
+
+	_, err = hash.Write([]byte(message))
+	if err != nil {
+		return "", err
+	}
+
+	hb := hash.Sum(nil)
+	s := base64.StdEncoding.EncodeToString(hb)
+
+	return s, nil
+}

b64/hmac_test.go

@@ -0,0 +1,30 @@
+package b64_test
+
+import (
+	"testing"
+
+	"github.com/zeiss/pkg/b64"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestContentHash(t *testing.T) {
+	t.Parallel()
+
+	content := []byte("test content")
+	hash, err := b64.ContentHash(content)
+	require.NoError(t, err)
+	assert.Equal(t, "auinVVUgn9bEQVfArtgBbnY/9DWhnPGG92hjFAFD/3I=", hash)
+}
+
+func TestHmac256(t *testing.T) {
+	t.Parallel()
+
+	message := "test message"
+	secret := "c2VjcmV0"
+
+	hash, err := b64.Hmac256(message, secret)
+	require.NoError(t, err)
+	assert.Equal(t, "O86/Q8hdILum47a6J4rx0ro6sNV94nGwrTC4M+hRxaY=", hash)
+}