diff --git a/internal/crypto/password.go b/internal/crypto/password.go
index 0505651b3..a09811d1e 100644
--- a/internal/crypto/password.go
+++ b/internal/crypto/password.go
@@ -2,6 +2,8 @@ package crypto
 
 import (
 	"context"
+	"crypto/aes"
+	"crypto/cipher"
 	"crypto/subtle"
 	"encoding/base64"
 	"errors"
@@ -321,19 +323,21 @@ func compareHashAndPasswordScrypt(ctx context.Context, hash, password string) er
 }
 
 func firebaseScrypt(password, salt, signerKey []byte, N, r, p uint64, keyLen int) ([]byte, error) {
-	// Step 1: Use standard scrypt to derive an intermediate key
-	intermediateKey, err := scrypt.Key(password, salt, int(N), int(r), int(p), 32)
+
+	ck, err := scrypt.Key(password, salt, 1<<N, int(r), int(p), keyLen)
 	if err != nil {
 		return nil, err
 	}
 
-	// Step 2: Use the intermediate key to derive the final key
-	result, err := scrypt.Key(intermediateKey, signerKey, 256, 8, 1, keyLen)
-	if err != nil {
+	var block cipher.Block
+	if block, err = aes.NewCipher(ck); err != nil {
 		return nil, err
 	}
 
-	return result, nil
+	cipherText := make([]byte, aes.BlockSize+len(signerKey))
+	stream := cipher.NewCTR(block, cipherText[:aes.BlockSize])
+	stream.XORKeyStream(cipherText[aes.BlockSize:], signerKey)
+	return cipherText[aes.BlockSize:], nil
 }
 
 // CompareHashAndPassword compares the hash and