《基本要求》規定的 SSL 憑證內容

CA/Browser Forum 官方網站「Certificate Contents for Baseline SSL」頁面之非官方繁體中文翻譯。

Baseline Requirements for Contents of Publicly Trusted SSL/TLS Certificates

公開信賴 SSL/TLS 憑證內容於《基本要求》中的規定

Certificates conforming to the Baseline Requirements must comply with sections 9.1 and 9.2 of the Baseline Requirements as well as Appendices A and B. Here are the general requirements found in those parts of the Baseline Requirements:

遵循《基本要求》之憑證，須符合《基本要求》第 9.1 節、第 9.2 節以及附錄 A 與附錄 B 之規定。以下為上述部分於《基本要求》所載之一般要求：

編按：本段所引條號為 2013 年撰寫本頁時的《基本要求》1.0 版編號。現行《基本要求》（v2.2.7）已改採 RFC 3647 架構，第 9.1 節為「費用」、第 9.2 節為「財務責任」，與憑證內容無關；憑證剖繪現規定於第 7.1 節（憑證剖繪）、第 7.2 節（CRL 剖繪）與第 7.3 節（OCSP 剖繪）。附錄 A 現為「CAA 聯絡標籤」、附錄 B 現為「為 Onion 網域名稱簽發憑證」。

CA Certificates

憑證機構（CA）憑證

Recommended key strengths are at least 2048-bit RSA using SHA-256, SHA-384 or SHA-512 or Elliptic Curve using NIST P-256, P-384, or P-521.

建議之金鑰強度為至少 2048 位元 RSA 搭配 SHA-256、SHA-384 或 SHA-512，或使用 NIST P-256、P-384、P-521 之橢圓曲線（Elliptic Curve）。

No MD5, and 1024-bit RSA and SHA1 are grandfathered. — SHA-1 MAY be used with RSA keys until SHA-256 is supported widely by browsers used by a substantial portion of relying-parties worldwide, and a Root CA Certificate issued prior to 31 Dec. 2010 with an RSA key size less than 2048 bits may still serve as a trust anchor for Subscriber Certificates.

不得使用 MD5；1024 位元 RSA 與 SHA-1 則適用既有例外規定（grandfathered）。亦即，在全世界相當比例之信賴憑證者所使用的瀏覽器廣泛支援 SHA-256 之前，RSA 金鑰得（MAY）使用 SHA-1；此外，於 2010 年 12 月 31 日前簽發，且 RSA 金鑰長度小於 2048 位元之根憑證機構（Root CA）憑證，仍可作為用戶憑證之信賴根源（Trust Anchor）。

編按：本段所述之過渡期安排早已失效。現行金鑰長度規定見第 6.1.5 節，簽章演算法規定見第 7.1.3.2 節——SHA-1 僅能用在符合條件的既有憑證、且只能於 2026-09-15 前使用。

basicConstraints

This extension MUST be present and MUST be marked critical. The cA field MUST be set true. The pathLenConstraint field MAY be present.

keyUsage

This extension MUST be present and MUST be marked critical. Bit positions for keyCertSign and cRLSign MUST be set. If the Private Key is used for signing OCSP responses, then the digitalSignature bit MUST be set.

basicConstraints

此擴充欄位應（MUST）存在，且應（MUST）標記為關鍵（critical）。cA 欄位應（MUST）設為 true。pathLenConstraint 欄位得（MAY）存在。
keyUsage

此擴充欄位應（MUST）存在，且應（MUST）標記為關鍵（critical）。keyCertSign 與 cRLSign 的旗標位元應（MUST）設定。若該私密金鑰用於簽章 OCSP 回應，則 digitalSignature 旗標位元應（MUST）設定。

All Certificates

所有憑證

CA shall not issue Certificates containing a keyUsage flag, extendedKeyUsage value, Certificate extension, or other data not specified unless the CA is aware of a reason for including the data in the Certificate. CAs SHALL NOT issue a Certificate with:

(a) Extensions that do not apply in the context of the public Internet (such as an extendedKeyUsage value for a service that is only valid in the context of a privately managed network), unless:

such value falls within an OID arc for which the Applicant demonstrates ownership, or

the Applicant can otherwise demonstrate the right to assert the data in a public context; or

(b) semantics that, if included, will mislead a Relying Party about the certificate information verified by the CA (such as including extendedKeyUsage value for a smart card, where the CA is not able to verify that the corresponding Private Key is confined to such hardware due to remote issuance).

除非 CA 知悉將憑證包含該資料之理由，否則 CA 不應簽發含有未經規定之 keyUsage 旗標、extendedKeyUsage 值、憑證擴充欄位或其他資料之憑證。CA 不得（SHALL NOT）簽發具有下列情形的憑證：

（a）不適用於公共網際網路的擴充欄位（例如，僅在私有管理網路底下有效之服務所使用的 extendedKeyUsage 值），除非：
- 1. 該值位於申請者能證明擁有其所有權之 OID arc 範圍內；或
- 1. 申請者能以其他方式證明其有權於公共網際網路中聲明該資料；或
（b）具有可能使信賴憑證者對 CA 所驗證之憑證資訊產生誤解的含義（例如，憑證包含智慧卡專用之 extendedKeyUsage 值，而 CA 因採行遠端簽發，無法驗證對應之私密金鑰是否確實僅存在於該硬體內）。

Subscriber Certificates

用戶憑證

certificatePolicies

This extension MUST be present and SHOULD NOT be marked critical. certificatePolicies:policyIdentifier (Required)

A Policy Identifier, defined by the issuing CA, that indicates a Certificate Policy asserting the issuing CA’s adherence to and compliance with these Requirements.

The following extensions MAY be present: certificatePolicies:policyQualifiers:policyQualifierId (Recommended)

id-qt 1 [RFC 5280].

certificatePolicies:policyQualifiers:qualifier:cPSuri (Optional)

HTTP URL for the Subordinate CA’s Certification Practice Statement, Relying Party Agreement or other pointer to online information provided by the CA.

certificatePolicies

此擴充欄位應（MUST）存在，且不宜（SHOULD NOT）標記為關鍵。

certificatePolicies:policyIdentifier（必要）
- 由簽發憑證機構（issuing CA）所定義之政策識別碼，用以表示簽發憑證機構（issuing CA）遵守並遵循本文件要求規定之憑證政策。
下列擴充欄位得（MAY）存在：

certificatePolicies:policyQualifiers:policyQualifierId（建議）
- 值為 id-qt 1 [RFC 5280]。
certificatePolicies:policyQualifiers:qualifier:cPSuri（選用）
- 下屬憑證機構（Subordinate CA）之憑證實務作業基準（CPS）、信賴憑證者協議（Relying Party Agreement），或其他由 CA 提供的線上資訊之 HTTP URL。

cRLDistributionPoints

This extension MAY be present. If present, it MUST NOT be marked critical, and it MUST contain the HTTP URL of the CA’s CRL service. See Section 13.2.1 for details.

cRLDistributionPoints

此擴充欄位得（MAY）存在。若存在，則不得（MUST NOT）標記為關鍵，且應（MUST）包含該 CA 之 CRL 服務的 HTTP URL。詳見第 13.2.1 節。

authorityInformationAccess

With the exception of stapling, which is noted below, this extension MUST be present. It MUST NOT be marked critical, and it MUST contain the HTTP URL of the Issuing CA’s OCSP responder (accessMethod = 1.3.6.1.5.5.7.48.1). It SHOULD also contain the HTTP URL of the Issuing CA’s certificate (accessMethod = 1.3.6.1.5.5.7.48.2). See Section 13.2.1 for details. The HTTP URL of the Issuing CA’s OCSP responder MAY be omitted provided that the Subscriber “staples” OCSP responses for the Certificate in its TLS handshakes [RFC4366].

authorityInformationAccess

除下述 stapling 情形外，此擴充欄位應（MUST）存在。該擴充欄位不得（MUST NOT）標記為關鍵，且應（MUST）包含簽發憑證機構（issuing CA）之 OCSP 回應伺服器的 HTTP URL（accessMethod = 1.3.6.1.5.5.7.48.1）。該擴充欄位亦宜（SHOULD）包含簽發憑證機構（issuing CA）憑證的 HTTP URL（accessMethod = 1.3.6.1.5.5.7.48.2）。詳見第 13.2.1 節。若用戶於其 TLS 連線交握中對該憑證進行 OCSP stapling [RFC4366]，則簽發憑證機構（issuing CA）之 OCSP 回應伺服器的 HTTP URL 得（MAY）省略。

編按：上兩段的「第 13.2.1 節」為《基本要求》1.0 版章節編號，現行版本並無第 13 章（最高為第 9 章）。另外，現行第 7.1.2.7.7 節已將 id-ad-ocsp（OCSP 回應伺服器 URL）改為得（MAY），不再是必要欄位；CRL 與 OCSP 之簽發與可用性規定見第 4.9.7 節與第 4.9.9 節。certificatePolicies 之現行規定見第 7.1.2.7.9 節。

basicConstraints (optional)

If present, the cA field MUST be set false.

keyUsage (optional)

If present, bit positions for keyCertSign and cRLSign MUST NOT be set.

extKeyUsage (required)

Either the value id-kp-serverAuth [RFC5280] or id-kp-clientAuth [RFC5280] or both values MUST be present. id-kp-emailProtection [RFC5280] MAY be present. Other values SHOULD NOT be present.

basicConstraints（選用）

若存在，cA 欄位應（MUST）設為 false。
keyUsage（選用）

若存在，keyCertSign 與 cRLSign 的旗標位元不得（MUST NOT）設定。
extKeyUsage（必要）

應（MUST）存在 id-kp-serverAuth [RFC5280] 或 id-kp-clientAuth [RFC5280] 其中之一，或兩者皆存在。id-kp-emailProtection [RFC5280] 得（MAY）存在。其他值則不宜（SHOULD NOT）存在。

編按：extKeyUsage 的規定已變更。依現行第 7.1.2.7.10 節，用戶憑證中 id-kp-emailProtection 為不得（MUST NOT）存在，與本頁所述「得存在」相反。引用時請以現行《基本要求》規定為準。