憑證廢止清冊（CRL）及 CRL 條目之擴充欄位

CRL and CRL entry extensions

CRL Extensions

Extension	Presence	Critical	Description
authorityKeyIdentifier	MUST	N	See Section 7.1.2.11.1
CRLNumber	MUST	N	MUST contain an INTEGER greater than or equal to zero (0) and less than 2¹⁵⁹, and convey a strictly increasing sequence.
IssuingDistributionPoint	*	Y	See Section 7.2.2.1 CRL Issuing Distribution Point
Any other extension	NOT RECOMMENDED	-	-

revokedCertificates Component

Component	Presence	Description
serialNumber	MUST	MUST be byte-for-byte identical to the serialNumber contained in the revoked Certificate.
revocationDate	MUST	Normally, the date and time revocation occurred. See the footnote following this table for circumstances where backdating is permitted.
crlEntryExtensions	*	See the “crlEntryExtensions Component” table for additional requirements.

Note: The CA SHOULD update the revocation date in a CRL entry when it is determined that the private key of the Certificate was compromised prior to the revocation date that is indicated in the CRL entry for that Certificate. Backdating the revocationDate field is an exception to best practice described in RFC 5280, Section 5.3.2; however, these requirements specify the use of the revocationDate field to support TLS implementations that process the revocationDate field as the date when the Certificate is first considered to be compromised.

注意：若確定憑證的私密金鑰（Private Key）在該憑證的 CRL 條目所載之廢止日期前即已遭破解（compromise），CA 宜（SHOULD）更新該 CRL 條目中的廢止日期。倒填 revocationDate 欄位屬於 RFC 5280 第 5.3.2 節 所述最佳實務之例外；然而，本節要求指定使用 revocationDate 欄位，以支援將該欄位所載日期視為憑證首次被認定已遭破解之日期的 TLS 實作。

crlEntryExtensions Component

CRL Entry Extension	Presence	Description
reasonCode	*	When present (OID 2.5.29.21), MUST NOT be marked critical and MUST indicate the most appropriate reason for revocation of the Certificate. MUST be present unless the CRL entry is for a Certificate not technically capable of causing issuance and either 1) the CRL entry is for a Subscriber Certificate subject to these Requirements revoked prior to 2023-07-15 or 2) the reason for revocation (i.e., reasonCode) is unspecified (0). See the “CRLReasons” table for additional requirements.
Any other value	NOT RECOMMENDED	-

CRLReasons

RFC 5280 reasonCode	RFC 5280 reasonCode value	Description
unspecified	0	Represented by the omission of a reasonCode. MUST be omitted if the CRL entry is for a Certificate not technically capable of causing issuance unless the CRL entry is for a Subscriber Certificate subject to these Requirements revoked prior to 2023-07-15.
keyCompromise	1	Indicates that it is known or suspected that the Subscriber’s Private Key has been compromised.
affiliationChanged	3	Indicates that the Subject’s name or other Subject Identity Information in the Certificate has changed, but there is no cause to suspect that the Certificate’s Private Key has been compromised.
superseded	4	Indicates that the Certificate is being replaced because: the Subscriber has requested a new Certificate, the CA has reasonable evidence that the validation of domain authorization or control for any fully-qualified domain name or IP address in the Certificate should not be relied upon, or the CA has revoked the Certificate for compliance reasons such as the Certificate does not comply with these Baseline Requirements or the CA’s CP or CPS.
cessationOfOperation	5	Indicates that the website with the Certificate is shut down prior to the expiration of the Certificate, or if the Subscriber no longer owns or controls the Domain Name in the Certificate prior to the expiration of the Certificate.
certificateHold	6	MUST NOT be included if the CRL entry is for 1) a Certificate subject to these Requirements, or 2) a Certificate not subject to these Requirements and was either A) issued on-or-after 2020-09-30 or B) has a notBefore on-or-after 2020-09-30.
privilegeWithdrawn	9	Indicates that there has been a subscriber-side infraction that has not resulted in keyCompromise, such as the Certificate Subscriber provided misleading information in their Certificate Request or has not upheld their material obligations under the Subscriber Agreement or Terms of Use.

The Subscriber Agreement, or an online resource referenced therein, MUST inform Subscribers about the revocation reason options listed above and provide explanation about when to choose each option. Tools that the CA provides to the Subscriber MUST allow for these options to be easily specified when the Subscriber requests revocation of their Certificate, with the default value being that no revocation reason is provided (i.e. the default corresponds to the CRLReason “unspecified (0)” which results in no reasonCode extension being provided in the CRL).

用戶協議（Subscriber Agreement）或其中所參照的線上資源，應（MUST）告知用戶上述的廢止原因選項，並說明各選項應於何種情形下選用。CA 提供給用戶的工具，應（MUST）允許用戶於請求廢止其憑證時，能輕易指定上述的選項；其預設值應為不提供廢止原因（即預設值對應於 CRLReason「unspecified (0)」，因此 CRL 中不提供 reasonCode 擴充欄位）。

The privilegeWithdrawn reasonCode SHOULD NOT be made available to the Subscriber as a revocation reason option, because the use of this reasonCode is determined by the CA and not the Subscriber.

privilegeWithdrawn reasonCode 不宜（SHOULD NOT）作為供用戶選擇的廢止原因選項，因為是否使用此 reasonCode 是由 CA 決定，而非由用戶決定。

When a CA obtains verifiable evidence of Key Compromise for a Certificate whose CRL entry does not contain a reasonCode extension or has a reasonCode extension with a non-keyCompromise reason, the CA SHOULD update the CRL entry to enter keyCompromise as the CRLReason in the reasonCode extension.

若 CA 取得某憑證金鑰遭破解（Key Compromise）的可查證證據，而該憑證的 CRL 條目不含 reasonCode 擴充欄位，或其 reasonCode 擴充欄位所載原因並非 keyCompromise，則 CA 宜（SHOULD）更新該 CRL 條目，將 reasonCode 擴充欄位中的 CRLReason 設為 keyCompromise。