管理 S/MIME 证书

Gmail S/MIME API 提供程序化访问权限，以便为网域中的用户管理 S/MIME 电子邮件证书。 Google Workspace

管理员必须为网域启用 S/MIME 才能使证书生效。

S/MIME 标准提供了 MIME 数据的公钥加密和签名规范。如果在用户帐号中配置 S/MIME 证书，Gmail 会通过以下方式使用该证书：

• Gmail 使用用户的证书和私钥对外发邮件进行签名。
• Gmail 使用用户的私钥来解密收到的邮件。
• Gmail 使用收件人的证书和公钥来加密外发邮件。
• Gmail 会使用发件人的证书和公钥来验证收到的邮件。

您可以生成单个 S/MIME 证书，然后使用 API 上传这些证书。每个 S/MIME 证书对应于用户电子邮件帐号的特定别名。 别名包括主电子邮件地址和自定义的“用以下地址发送”地址。 系统会将一个 S/MIME 证书标记为每个别名的默认证书。

授予 API 访问权限

授权访问 API 的方式有两种：

1. 您可以将服务帐号与全网域授权结合使用。 如需了解这些术语的说明，请参阅身份验证和授权概览术语。如需了解如何启用此选项，请参阅创建具有全网域授权功能的服务帐号
2. 您可以使用需要最终用户同意的标准 OAuth2 流程来获取 Oauth2 访问令牌。如需了解详情，请参阅身份验证和授权概览。要使用此选项，网域管理员必须在“网域”控制面板中启用“S/MIME API 最终用户访问权限已启用”复选框。

ACL 范围

此 API 依赖于与 Gmail sendAs 方法相同的 ACL 范围：

gmail.settings.basic

更新主 SendAs S/MIME 时，必须使用此范围。

gmail.settings.sharing

如要更新自定义 S/MIME 数据，必须使用此范围。

使用 API

users.settings.sendAs.smimeInfo 资源提供了用于管理 S/MIME 证书的方法。每个证书都与用户的一个“用以下地址发送邮件”别名关联。

注意 ：如需确定用户存在的“用以下地址发送邮件”别名，请使用 sendAs.list() 方法。

上传 S/MIME 密钥

使用 smimeInfo.insert() 方法为属于用户的别名上传新的 S/MIME 密钥。 您可以使用以下参数标识目标别名：

userId

用户的电子邮件地址。您可以使用特殊值 me 来指示当前经过身份验证的用户。

sendAsEmail

要为其上传密钥的别名。对于使用此别名发送的邮件，该地址会显示在邮件的“发件人：”标头中。

S/MIME 证书和私钥应以该格式显示在 pkcs12 字段中；不应在请求中设置任何其他字段。PKCS12 字段应同时包含用户 S/MIME 密钥和签名证书链。API 在接受此字段之前会对此字段执行标准验证，以验证以下内容：

• 主题与指定的电子邮件地址匹配。
• 失效时间有效。
• 颁发证书的证书授权机构 (CA) 在我们的受信任列表中。
• 这些证书符合 Gmail 的技术限制。

如果密钥经过加密，则密码应该位于 encryptedKeyPassword 字段中。成功的 insert() 调用将返回 smimeInfo 的 ID，该 ID 可用于将来引用相应密钥。

列出用户的 S/MIME 密钥

使用 smimeInfo.list() 方法返回针对指定别名的指定用户的 S/MIME 密钥列表。您可以使用以下参数标识目标别名：

userId

用户的电子邮件地址。您可以使用特殊值 me 来指示当前经过身份验证的用户。

sendAsEmail

要列出其键的别名。对于使用此别名发送的邮件，该地址会显示在邮件的“发件人：”标头中。

密钥仅以 pem 格式返回，且仅包含 S/MIME 证书，不包含私钥。

检索别名的 S/MIME 密钥

使用 smimeInfo.get() 方法可返回用户的特定“用以下地址发送邮件”别名的特定 S/MIME 密钥。 您可以使用以下参数标识目标别名：

userId

用户的电子邮件地址。您可以使用特殊值 me 来指示当前经过身份验证的用户。

sendAsEmail

要检索其密钥的别名。对于使用此别名发送的邮件，该地址会显示在邮件的“发件人：”标头中。

密钥仅以 pem 格式返回，且仅包含 S/MIME 证书，不包含私钥。

删除 S/MIME 密钥

可以使用 smimeInfo.delete() 方法从别名中删除指定的 S/MIME 密钥。 您可以使用以下参数标识目标别名：

userId

用户的电子邮件地址。您可以使用特殊值 me 来指示当前经过身份验证的用户。

sendAsEmail

要检索其密钥的别名。对于使用此别名发送的邮件，该地址会显示在邮件的“发件人：”标头中。

id

SmimeInfo 的不可变 ID。

已删除的密钥不再可见或不再可用，且收到的使用相应公钥加密的 S/MIME 电子邮件无法解密。因此，建议在删除密钥之前，由其颁发机构 (CA) 撤消该密钥。

为别名设置默认 S/MIME 密钥

使用 smimeInfo.setDefault() 方法将指定的 S/MIME 密钥标记为指定别名的默认密钥。 您可以使用以下参数标识目标别名：

userId

用户的电子邮件地址。您可以使用特殊值 me 来指示当前经过身份验证的用户。

sendAsEmail

要检索其密钥的别名。对于使用此别名发送的邮件，该地址会显示在邮件的“发件人：”标头中。

id

SmimeInfo 的不可变 ID。

用户 SendAs 只有一个默认 S/MIME 密钥：调用 setDefault() 会取消设置之前的默认设置。

在接收使用给定密钥签名的 S/MIME 邮件时，Gmail 会在对发送给关联用户的邮件进行加密时，将该密钥与最远的 not_before 有效期相关联。为了确保已与其通信的 Gmail 用户使用新默认密钥，请确保新默认密钥的 not_before 日期晚于前一默认密钥，或撤消旧默认密钥。

示例代码

以下代码示例演示了如何使用 API 为拥有多用户的组织的 S/MIME 证书。

为 S/MIME 证书创建 SmimeInfo 资源

以下代码示例演示了如何从文件中读取证书、编码为 base64url 字符串，以及将其分配给 smimeInfo 资源的 pkcs12 字段：

Java

gmail/snippets/src/main/java/CreateSmimeInfo.java

在 GitHub 上查看

import com.google.api.services.gmail.model.SmimeInfo;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Base64;

/* Class to demonstrate the use of Gmail Create SmimeInfo API */
public class CreateSmimeInfo {
  /**
   * Create an SmimeInfo resource for a certificate from file.
   *
   * @param filename Name of the file containing the S/MIME certificate.
   * @param password Password for the certificate file, or null if the file is not
   *                 password-protected.
   * @return An SmimeInfo object with the specified certificate.
   */
  public static SmimeInfo createSmimeInfo(String filename, String password) {
    SmimeInfo smimeInfo = null;
    InputStream in = null;

    try {
      File file = new File(filename);
      in = new FileInputStream(file);
      byte[] fileContent = new byte[(int) file.length()];
      in.read(fileContent);

      smimeInfo = new SmimeInfo();
      smimeInfo.setPkcs12(Base64.getUrlEncoder().encodeToString(fileContent));
      if (password != null && password.length() > 0) {
        smimeInfo.setEncryptedKeyPassword(password);
      }
    } catch (Exception e) {
      System.out.printf("An error occured while reading the certificate file: %s\n", e);
    } finally {
      try {
        if (in != null) {
          in.close();
        }
      } catch (IOException ioe) {
        System.out.printf("An error occured while closing the input stream: %s\n", ioe);
      }
    }
    return smimeInfo;
  }
}

Python

gmail/snippet/smime 摘要/create_smime_info.py

在 GitHub 上查看

import base64


def create_smime_info(cert_filename, cert_password):
  """Create an smimeInfo resource for a certificate from file.
  Args:
    cert_filename: Name of the file containing the S/MIME certificate.
    cert_password: Password for the certificate file, or None if the file is not
        password-protected.
  Returns : Smime object, including smime information
  """

  smime_info = None
  try:
    with open(cert_filename, "rb") as cert:
      smime_info = {}
      data = cert.read().encode("UTF-8")
      smime_info["pkcs12"] = base64.urlsafe_b64encode(data).decode()
      if cert_password and len(cert_password) > 0:
        smime_info["encryptedKeyPassword"] = cert_password

  except (OSError, IOError) as error:
    print(f"An error occurred while reading the certificate file: {error}")
    smime_info = None

  return smime_info


if __name__ == "__main__":
  print(create_smime_info(cert_filename="xyz", cert_password="xyz"))

上传 S/MIME 证书

如需上传证书，请调用 smimeInfo.insert，并在请求正文中提供 smimeInfo 资源：

Java

gmail/snippets/src/main/java/InsertSmimeInfo.java

在 GitHub 上查看

import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.SmimeInfo;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
import java.io.IOException;

/* Class to demonstrate the use of Gmail Insert Smime Certificate API*/
public class InsertSmimeInfo {
  /**
   * Upload an S/MIME certificate for the user.
   *
   * @param userId      User's email address.
   * @param sendAsEmail The "send as" email address, or null if it should be the same as userId.
   * @param smimeInfo   The SmimeInfo object containing the user's S/MIME certificate.
   * @return An SmimeInfo object with details about the uploaded certificate, {@code null} otherwise.
   * @throws IOException - if service account credentials file not found.
   */
  public static SmimeInfo insertSmimeInfo(String userId,
                                          String sendAsEmail,
                                          SmimeInfo smimeInfo)
      throws IOException {
        /* Load pre-authorized user credentials from the environment.
           TODO(developer) - See https://developers.google.com/identity for
            guides on implementing OAuth2 for your application. */
    GoogleCredentials credentials = GoogleCredentials.getApplicationDefault()
        .createScoped(GmailScopes.GMAIL_SETTINGS_SHARING);
    HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(
        credentials);

    // Create the gmail API client
    Gmail service = new Gmail.Builder(new NetHttpTransport(),
        GsonFactory.getDefaultInstance(),
        requestInitializer)
        .setApplicationName("Gmail samples")
        .build();

    if (sendAsEmail == null) {
      sendAsEmail = userId;
    }

    try {
      SmimeInfo results = service.users().settings().sendAs().smimeInfo()
          .insert(userId, sendAsEmail, smimeInfo)
          .execute();
      System.out.printf("Inserted certificate, id: %s\n", results.getId());
      return results;
    } catch (IOException e) {
      System.err.printf("An error occured: %s", e);
    }
    return null;
  }
}

Python

gmail/snippet/smime 代码段/insert_smime_info.py

在 GitHub 上查看

import create_smime_info
import google.auth
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError


def insert_smime_info():
  """Upload an S/MIME certificate for the user.
  Print the inserted certificate's id
  Returns : Result object with inserted certificate id and other meta-data

  Load pre-authorized user credentials from the environment.
  TODO(developer) - See https://developers.google.com/identity
  for guides on implementing OAuth2 for the application.
  """
  creds, _ = google.auth.default()

  try:
    # create gmail api client
    service = build("gmail", "v1", credentials=creds)

    user_id = "[e-mail]"
    smime_info = create_smime_info.create_smime_info(
        cert_filename="xyz", cert_password="xyz"
    )
    send_as_email = None

    if not send_as_email:
      send_as_email = user_id

    # pylint: disable=maybe-no-member
    results = (
        service.users()
        .settings()
        .sendAs()
        .smimeInfo()
        .insert(userId=user_id, sendAsEmail=send_as_email, body=smime_info)
        .execute()
    )
    print(f'Inserted certificate; id: {results["id"]}')

  except HttpError as error:
    print(f"An error occurred: {error}")
    results = None

  return results


if __name__ == "__main__":
  insert_smime_info()

管理多个用户证书的示例

您可能希望一次为组织中的许多用户管理证书。 以下示例展示了如何通过一次批量调用管理多个用户的证书。

从 CSV 文件插入证书

假设您有一个 CSV 文件，其中列出了用户 ID 和每个用户证书的路径：

$ cat certificates.csv
[e-mail],/path/to/user1_cert.p12,cert_password_1
[e-mail],/path/to/user2_cert.p12,cert_password_2
[e-mail],/path/to/user3_cert.p12,cert_password_3

Java

您可以利用之前的 createSmimeInfo 和 insertSmimeInfo 调用来上传 CSV 文件中指定的证书：

gmail/snippets/src/main/java/InsertCertFromCsv.java

在 GitHub 上查看

import com.google.api.services.gmail.model.SmimeInfo;
import java.io.File;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;

/* Class to demonstrate the use of Gmail Insert Certificate from CSV File */
public class InsertCertFromCsv {
  /**
   * Upload S/MIME certificates based on the contents of a CSV file.
   *
   * <p>Each row of the CSV file should contain a user ID, path to the certificate, and the
   * certificate password.
   *
   * @param csvFilename Name of the CSV file.
   */
  public static void insertCertFromCsv(String csvFilename) {
    try {
      File csvFile = new File(csvFilename);
      CSVParser parser =
          CSVParser.parse(csvFile, java.nio.charset.StandardCharsets.UTF_8, CSVFormat.DEFAULT);
      for (CSVRecord record : parser) {
        String userId = record.get(0);
        String certFilename = record.get(1);
        String certPassword = record.get(2);
        SmimeInfo smimeInfo = CreateSmimeInfo.createSmimeInfo(certFilename,
            certPassword);
        if (smimeInfo != null) {
          InsertSmimeInfo.insertSmimeInfo(userId,
              userId,
              smimeInfo);
        } else {
          System.err.printf("Unable to read certificate file for userId: %s\n", userId);
        }
      }
    } catch (Exception e) {
      System.err.printf("An error occured while reading the CSV file: %s", e);
    }
  }
}

Python

您可以利用之前的 create_smime_info 和 insert_smime_info 调用来上传 CSV 文件中指定的证书：

gmail/snippet/smime 短片段/insert_cert_from_csv.py

在 GitHub 上查看

import csv

import create_smime_info
import insert_smime_info


def insert_cert_from_csv(csv_filename):
  """Upload S/MIME certificates based on the contents of a CSV file.
  Each row of the CSV file should contain a user ID, path to the certificate,
  and the certificate password.

  Args:
    csv_filename: Name of the CSV file.
  """

  try:
    with open(csv_filename, "rb") as cert:
      csv_reader = csv.reader(cert, delimiter=",")
      next(csv_reader, None)  # skip CSV file header
      for row in csv_reader:
        user_id = row[0]
        cert_filename = row[1]
        cert_password = row[2]
        smime_info = create_smime_info.create_smime_info(
            cert_filename=cert_filename, cert_password=cert_password
        )
        if smime_info:
          insert_smime_info.insert_smime_info()
        else:
          print(f"Unable to read certificate file for user_id: {user_id}")
        return smime_info

  except (OSError, IOError) as error:
    print(f"An error occured while reading the CSV file: {error}")


if __name__ == "__main__":
  insert_cert_from_csv(csv_filename="xyz")

证书管理

此示例结合了来自 smimeInfo API 的多次调用，以展示您可以如何管理组织的证书。它会列出用户的证书，如果默认证书已过期或未设置，它会上传在指定文件中找到的证书。然后，它会将过期最远的证书设置为默认证书。

然后，通过处理 CSV 文件的函数调用此方法，如上例所示。

Java

gmail/snippets/src/main/java/UpdateSmimeCerts.java

在 GitHub 上查看

import com.google.api.client.http.HttpRequestInitializer;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.ListSmimeInfoResponse;
import com.google.api.services.gmail.model.SmimeInfo;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
import java.io.IOException;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;

/* Class to demonstrate the use of Gmail Update Smime Certificate API*/
public class UpdateSmimeCerts {
  /**
   * Update S/MIME certificates for the user.
   *
   * <p>First performs a lookup of all certificates for a user. If there are no certificates, or
   * they all expire before the specified date/time, uploads the certificate in the specified file.
   * If the default certificate is expired or there was no default set, chooses the certificate with
   * the expiration furthest into the future and sets it as default.
   *
   * @param userId       User's email address.
   * @param sendAsEmail  The "send as" email address, or None if it should be the same as user_id.
   * @param certFilename Name of the file containing the S/MIME certificate.
   * @param certPassword Password for the certificate file, or None if the file is not
   *                     password-protected.
   * @param expireTime   DateTime object against which the certificate expiration is compared. If
   *                     None, uses the current time. @ returns: The ID of the default certificate.
   * @return The ID of the default certificate, {@code null} otherwise.
   * @throws IOException - if service account credentials file not found.
   */
  public static String updateSmimeCerts(String userId,
                                        String sendAsEmail,
                                        String certFilename,
                                        String certPassword,
                                        LocalDateTime expireTime)
      throws IOException {
        /* Load pre-authorized user credentials from the environment.
           TODO(developer) - See https://developers.google.com/identity for
            guides on implementing OAuth2 for your application. */
    GoogleCredentials credentials = GoogleCredentials.getApplicationDefault()
        .createScoped(GmailScopes.GMAIL_SETTINGS_SHARING);
    HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(
        credentials);

    // Create the gmail API client
    Gmail service = new Gmail.Builder(new NetHttpTransport(),
        GsonFactory.getDefaultInstance(),
        requestInitializer)
        .setApplicationName("Gmail samples")
        .build();

    if (sendAsEmail == null) {
      sendAsEmail = userId;
    }

    ListSmimeInfoResponse listResults;
    try {
      listResults =
          service.users().settings().sendAs().smimeInfo().list(userId, sendAsEmail).execute();
    } catch (IOException e) {
      System.err.printf("An error occurred during list: %s\n", e);
      return null;
    }

    String defaultCertId = null;
    String bestCertId = null;
    LocalDateTime bestCertExpire = LocalDateTime.MIN;

    if (expireTime == null) {
      expireTime = LocalDateTime.now();
    }
    if (listResults != null && listResults.getSmimeInfo() != null) {
      for (SmimeInfo smimeInfo : listResults.getSmimeInfo()) {
        String certId = smimeInfo.getId();
        boolean isDefaultCert = smimeInfo.getIsDefault();
        if (isDefaultCert) {
          defaultCertId = certId;
        }
        LocalDateTime exp =
            LocalDateTime.ofInstant(
                Instant.ofEpochMilli(smimeInfo.getExpiration()), ZoneId.systemDefault());
        if (exp.isAfter(expireTime)) {
          if (exp.isAfter(bestCertExpire)) {
            bestCertId = certId;
            bestCertExpire = exp;
          }
        } else {
          if (isDefaultCert) {
            defaultCertId = null;
          }
        }
      }
    }
    if (defaultCertId == null) {
      String defaultId = bestCertId;
      if (defaultId == null && certFilename != null) {
        SmimeInfo smimeInfo = CreateSmimeInfo.createSmimeInfo(certFilename,
            certPassword);
        SmimeInfo insertResults = InsertSmimeInfo.insertSmimeInfo(userId,
            sendAsEmail,
            smimeInfo);
        if (insertResults != null) {
          defaultId = insertResults.getId();
        }
      }

      if (defaultId != null) {
        try {
          service.users().settings().sendAs().smimeInfo().setDefault(userId, sendAsEmail, defaultId)
              .execute();
          return defaultId;
        } catch (IOException e) {
          System.err.printf("An error occured during setDefault: %s", e);
        }
      }
    } else {
      return defaultCertId;
    }

    return null;
  }
}

Python

gmail/snippet/smime 代码段/update_smime_cert.py

在 GitHub 上查看

from datetime import datetime

import create_smime_info
import google.auth
import insert_smime_info
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError


def update_smime_cert(
    user_id, send_as_email, cert_filename, cert_password, expire_dt
):
  """Update S/MIME certificates for the user.

  First performs a lookup of all certificates for a user.  If there are no
  certificates, or they all expire before the specified date/time, uploads the
  certificate in the specified file.  If the default certificate is expired or
  there was no default set, chooses the certificate with the expiration furthest
  into the future and sets it as default.

  Args:
    user_id: User's email address.
    send_as_email: The "send as" email address, or None if it should be the same
        as user_id.
    cert_filename: Name of the file containing the S/MIME certificate.
    cert_password: Password for the certificate file, or None if the file is not
        password-protected.
    expire_dt: DateTime object against which the certificate expiration is
      compared.  If None, uses the current time.

  Returns:
    The ID of the default certificate.

  Load pre-authorized user credentials from the environment.
  TODO(developer) - See https://developers.google.com/identity
  for guides on implementing OAuth2 for the application.
  """
  if not send_as_email:
    send_as_email = user_id

  creds, _ = google.auth.default()

  try:
    # create gmail api client
    service = build("gmail", "v1", credentials=creds)

    # pylint: disable=maybe-no-member
    results = (
        service.users()
        .settings()
        .sendAs()
        .smimeInfo()
        .list(userId=user_id, sendAsEmail=send_as_email)
        .execute()
    )

  except HttpError as error:
    print(f"An error occurred during list: {error}")
    return None

  default_cert_id = None
  best_cert_id = (None, datetime.datetime.fromtimestamp(0))

  if not expire_dt:
    expire_dt = datetime.datetime.now()
  if results and "smimeInfo" in results:
    for smime_info in results["smimeInfo"]:
      cert_id = smime_info["id"]
      is_default_cert = smime_info["isDefault"]
      if is_default_cert:
        default_cert_id = cert_id
      exp = datetime.datetime.fromtimestamp(smime_info["expiration"] / 1000)
      if exp > expire_dt:
        if exp > best_cert_id[1]:
          best_cert_id = (cert_id, exp)
      else:
        if is_default_cert:
          default_cert_id = None

  if not default_cert_id:
    default_id = best_cert_id[0]
    if not default_id and cert_filename:
      create_smime_info.create_smime_info(
          cert_filename=cert_filename, cert_password=cert_password
      )
      results = insert_smime_info.insert_smime_info()
      if results:
        default_id = results["id"]

    if default_id:
      try:
        # pylint: disable=maybe-no-member
        service.users().settings().sendAs().smimeInfo().setDefault(
            userId=user_id, sendAsEmail=send_as_email, id=default_id
        ).execute()
        return default_id
      except HttpError as error:
        print(f"An error occurred during setDefault: {error}")
  else:
    return default_cert_id

  return None


if __name__ == "__main__":
  update_smime_cert(
      user_id="xyz",
      send_as_email=None,
      cert_filename="xyz",
      cert_password="xyz",
      expire_dt=None,
  )