From 6384e7eb4f339e0e3dcd92718eb6856dbc74caa1 Mon Sep 17 00:00:00 2001
From: renzhiyuan <465386466@qq.com>
Date: Mon, 17 Aug 2026 11:03:05 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E6=96=87=E4=BB=B6:=20crypto.?=
 =?UTF-8?q?go?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 crypto.go | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)
 create mode 100644 crypto.go

diff --git a/crypto.go b/crypto.go
new file mode 100644
index 0000000..f1bcf39
--- /dev/null
+++ b/crypto.go
@@ -0,0 +1,75 @@
+package intelligence_finance
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"math/big"
+	"sort"
+	"strings"
+	"time"
+)
+
+// GenerateTimestamp generates a Unix timestamp in seconds as a string.
+func GenerateTimestamp() string {
+	return fmt.Sprintf("%d", time.Now().Unix())
+}
+
+// GenerateTimestampMillis generates a Unix timestamp in milliseconds as a string.
+func GenerateTimestampMillis() string {
+	return fmt.Sprintf("%d", time.Now().UnixMilli())
+}
+
+// GenerateNonce generates a cryptographically secure random string of the given length.
+func GenerateNonce(length int) (string, error) {
+	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	b := make([]byte, length)
+	for i := range b {
+		num, err := rand.Int(rand.Reader, big.NewInt(int64(len(charset))))
+		if err != nil {
+			return "", fmt.Errorf("generate nonce: %w", err)
+		}
+		b[i] = charset[num.Int64()]
+	}
+	return string(b), nil
+}
+
+// HmacSHA256Base64 computes HmacSHA256 of the given data using the secret key,
+// and returns the result as a Base64-encoded string.
+func HmacSHA256Base64(secret, data string) string {
+	mac := hmac.New(sha256.New, []byte(secret))
+	mac.Write([]byte(data))
+	return base64.StdEncoding.EncodeToString(mac.Sum(nil))
+}
+
+// BuildSignString sorts parameters by key in dictionary order and concatenates
+// them as key=value&key2=value2, excluding empty values and the sign/signature fields.
+func BuildSignString(params map[string]string) string {
+	keys := make([]string, 0, len(params))
+	for k, v := range params {
+		if v != "" && k != "sign" && k != "signature" {
+			keys = append(keys, k)
+		}
+	}
+	sort.Strings(keys)
+
+	var parts []string
+	for _, k := range keys {
+		parts = append(parts, fmt.Sprintf("%s=%s", k, params[k]))
+	}
+	return strings.Join(parts, "&")
+}
+
+// BuildSignStringOrdered concatenates parameters in the specified key order,
+// excluding empty values.
+func BuildSignStringOrdered(params map[string]string, orderedKeys []string) string {
+	var parts []string
+	for _, k := range orderedKeys {
+		if v, ok := params[k]; ok && v != "" {
+			parts = append(parts, fmt.Sprintf("%s=%s", k, v))
+		}
+	}
+	return strings.Join(parts, "&")
+}
\ No newline at end of file