X509 证书：一个使用 High-tag-number form 编码的 Tag 示例证书

证书特点

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其中部分节点的 Tag 值超过了 30，使用的 High-tag-number form 编码， 比较少见。

ASN.1 相关编码规则

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ref: https://luca.ntop.org/Teaching/Appunti/asn1.html

Identifier octets. There are two forms: low tag number (for tag numbers between 0 and 30) and high tag number (for tag numbers 31 and greater).


Low-tag-number form. One octet. Bits 8 and 7 specify the class (see Table 2), bit 6 has value "0," indicating that the encoding is primitive, and bits 5-1 give the tag number.


High-tag-number form. Two or more octets. First octet is as in low-tag-number form, except that bits 5-1 all have value "1." Second and following octets give the tag number, base 128, most significant digit first, with as few digits as possible, and with the bit 8 of each octet except the last set to "1."

特殊部分

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SEQUENCE (8 elem)
	[1] (1 elem)
		SET (1 elem)
			INTEGER 2
	[2] (1 elem)
    	INTEGER 3
	[3] (1 elem)
		INTEGER 256
	[5] (1 elem)
		SET (1 elem)
			INTEGER 4
	[10] (1 elem)
		INTEGER 1
	[504] (1 elem)
		INTEGER 2
	[702] (1 elem)
		INTEGER 0
	[703] (1 elem)
		NULL

证书内容

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-----BEGIN CERTIFICATE-----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SN1rYv3g4XurBcHrkAHXnF7R4QIgEv3mZBbMf1TbK07t132dg+8CLfr0+p05Y3x2eM6lOcY=
-----END CERTIFICATE-----