PKCS15 PKCS15Object标记误解

Question

在使用ASN.1和解码PKCS #15令牌时，我发现我不理解为什么PKCS15Object的标记[0]和[1]是显式的而不是隐式的，因为它声明了with DEFINITIONS IMPLICIT TAGS子句。

PKCS-15 {iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
         pkcs-15(15) modules(1) pkcs-15(1)} 

-- $Revision: 1.7 $ --

DEFINITIONS IMPLICIT TAGS ::=

...

PKCS15Object {ClassAttributes, SubClassAttributes, TypeAttributes}
    ::= SEQUENCE {
    commonObjectAttributes  CommonObjectAttributes,
    classAttributes         ClassAttributes,
    subClassAttributes      [0] SubClassAttributes OPTIONAL <<--- explicit?,
    typeAttributes          [1] TypeAttributes              <<--- explicit?
}

PrivateKeyObject {KeyAttributes} ::= PKCS15Object { 
    CommonKeyAttributes, CommonPrivateKeyAttributes, KeyAttributes}

PrivateKeys  ::= PathOrObjects {PrivateKeyType}

PrivateKeyType ::= CHOICE {
    privateRSAKey   PrivateKeyObject {PrivateRSAKeyAttributes},
    privateECKey    [0] PrivateKeyObject {PrivateECKeyAttributes},
    ... -- For future extensions
}

PrivateRSAKeyAttributes ::= SEQUENCE {
    value           ObjectValue {RSAPrivateKeyObject},
    modulusLength   INTEGER, -- modulus length in bits, e.g. 1024
    keyInfo         KeyInfo {NULL, PublicKeyOperations} OPTIONAL,
    ... -- For future extensions
} 

拜托，谁给我解释一下。

Answer 1

其原因是X.680的细则31.2.7 (c)。您有一个正在标记的无标记DummyReference，因此您的标记是显式的。