二阶段差不多

internal/dkim/keys.go

@@ -0,0 +1,42 @@
+package dkim
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/pem"
+	"fmt"
+)
+
+// GenerateKeyPair 生成 2048 位 RSA 密钥对，返回 PEM 编码的私钥和公钥
+func GenerateKeyPair() (privateKeyPEM, publicKeyPEM string, err error) {
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return "", "", fmt.Errorf("生成RSA密钥对失败: %w", err)
+	}
+
+	privBytes := x509.MarshalPKCS1PrivateKey(key)
+	privPEM := pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: privBytes})
+
+	pubBytes, err := x509.MarshalPKIXPublicKey(&key.PublicKey)
+	if err != nil {
+		return "", "", fmt.Errorf("编码公钥失败: %w", err)
+	}
+	pubPEM := pem.EncodeToMemory(&pem.Block{Type: "PUBLIC KEY", Bytes: pubBytes})
+
+	return string(privPEM), string(pubPEM), nil
+}
+
+// GetDKIMDNSRecord 生成 DKIM DNS TXT 记录值
+// 格式: v=DKIM1; k=rsa; p=<base64公钥>
+func GetDKIMDNSRecord(publicKeyPEM string) string {
+	if publicKeyPEM == "" {
+		return ""
+	}
+	block, _ := pem.Decode([]byte(publicKeyPEM))
+	if block == nil {
+		return ""
+	}
+	return fmt.Sprintf("v=DKIM1; k=rsa; p=%s", base64.StdEncoding.EncodeToString(block.Bytes))
+}