feat: sdk migration in progress

internal/utils/crypto.go

@@ -0,0 +1,85 @@
+package utils
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"io"
+)
+
+var (
+	ErrNoActiveMasterKey   = errors.New("no active master key found")
+	ErrInvalidOrgID        = errors.New("invalid organization ID")
+	ErrCredentialNotFound  = errors.New("credential not found")
+	ErrInvalidMasterKeyLen = errors.New("invalid master key length")
+)
+
+func randomBytes(n int) ([]byte, error) {
+	b := make([]byte, n)
+	if _, err := io.ReadFull(rand.Reader, b); err != nil {
+		return nil, fmt.Errorf("rand: %w", err)
+	}
+	return b, nil
+}
+
+func encryptAESGCM(plaintext, key []byte) (cipherNoTag, iv, tag []byte, _ error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, nil, nil, fmt.Errorf("cipher: %w", err)
+	}
+
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, nil, nil, fmt.Errorf("gcm: %w", err)
+	}
+	if gcm.NonceSize() != 12 {
+		return nil, nil, nil, fmt.Errorf("unexpected nonce size: %d", gcm.NonceSize())
+	}
+
+	iv, err = randomBytes(gcm.NonceSize())
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	// Go’s GCM returns ciphertext||tag, with 16-byte tag.
+	cipherWithTag := gcm.Seal(nil, iv, plaintext, nil)
+	if len(cipherWithTag) < 16 {
+		return nil, nil, nil, errors.New("ciphertext too short")
+	}
+	tagLen := 16
+	cipherNoTag = cipherWithTag[:len(cipherWithTag)-tagLen]
+	tag = cipherWithTag[len(cipherWithTag)-tagLen:]
+	return cipherNoTag, iv, tag, nil
+}
+
+func decryptAESGCM(cipherNoTag, key, iv, tag []byte) ([]byte, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, fmt.Errorf("cipher: %w", err)
+	}
+	gcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return nil, fmt.Errorf("gcm: %w", err)
+	}
+	if gcm.NonceSize() != len(iv) {
+		return nil, fmt.Errorf("bad nonce size: %d", len(iv))
+	}
+	// Reattach tag
+	cipherWithTag := append(append([]byte{}, cipherNoTag...), tag...)
+	plain, err := gcm.Open(nil, iv, cipherWithTag, nil)
+	if err != nil {
+		return nil, fmt.Errorf("gcm open: %w", err)
+	}
+	return plain, nil
+}
+
+func EncodeB64(b []byte) string {
+	return base64.StdEncoding.EncodeToString(b)
+}
+
+func DecodeB64(s string) ([]byte, error) {
+	return base64.StdEncoding.DecodeString(s)
+}