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Yes, I mean “digital signature policy” as a “policy
document” present at SPUri. But I use SPUri only for example, you may specify
a SigPolicyId and omit sigPolicyQualifiers at all. In this case you have to
rely on some other means to convey a correspondence between SigPolicyIds and “policy
documents”. In case of SPuri you have to retrieve a “policy document”
by its URI and hash it. Note that if your infrastructure provides a trusted source of “policy
documents”, and there will never be two different (versions of) “policy
documents” identified by the same OID, you don’t have to hash them
at all. Just use zero policy hash value. Pavel Smirnov Crypto-Pro From:
owner-ietf-smime@xxxxxxxxxxxx [mailto:owner-ietf-smime@xxxxxxxxxxxx] On
Behalf Of Yasir Khan You wrote: ”You have to hash a digital signature policy
represented as a sequence of bytes in some format and place the computed value
in SigPolicyHash.” To which item you are naming as “digital signature
policy”. You mean policy document present at SPUri? If Yes then it makes
some sense. But if only SPUserNotice is present or nothing is present as sigPolicyQualifiers as it is an OPTIONAL element:
sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF SigPolicyQualifierInfo OPTIONAL then on which item the hash would be computed? Regards, Yasir Khan From: Pavel V. Smirnov [mailto:spv@xxxxxxxxxxxx] Hello Yasir, There is no need to protect by SigPolicyHash other fields of
SignaturePolicyId structure because it is placed in a signed attribute. All
signed attributes are protected by the signature itself. In most cases the policy would be an external document not
included in your signed message, and you have to unambiguously indicate
specific policy with respect to which your document should be treated. E.g.,
you may only have an URI pointing to the policy as a SigPolicyQualifier. You have to hash a digital signature policy represented as a
sequence of bytes in some format and place the computed value in SigPolicyHash. Pavel Smirnov Crypto-Pro From: owner-ietf-smime@xxxxxxxxxxxx
[mailto:owner-ietf-smime@xxxxxxxxxxxx] On Behalf Of Yasir Khan We
have a question related to using the signature policy in the CAdES signatures
(EPES) defined in RFC-5126. Here is the relevant structure: SignaturePolicyId
::= SEQUENCE {
sigPolicyIdentifier SigPolicyId,
sigPolicyHash SigPolicyHash,
sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF
SigPolicyQualifierInfo OPTIONAL } SigPolicyId
::= OBJECT IDENTIFIER SigPolicyHash ::= OtherHashAlgAndValue OtherHashAlgAndValue ::= SEQUENCE {
hashAlgorithm
AlgorithmIdentifier,
hashValue OtherHashValue } SigPolicyQualifierInfo
::= SEQUENCE {
sigPolicyQualifierId SigPolicyQualifierId,
sigQualifier ANY DEFINED BY sigPolicyQualifierId } SigPolicyQualifierId
::= OBJECT IDENTIFIER id-spq-ets-uri
OBJECT IDENTIFIER ::= {
iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16)
id-spq(5) 1 } SPuri
::= IA5String id-spq-ets-unotice
OBJECT IDENTIFIER ::= {
iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16)
id-spq(5) 2 } SPUserNotice
::= SEQUENCE {
noticeRef NoticeReference OPTIONAL,
explicitText DisplayText OPTIONAL } NoticeReference
::= SEQUENCE {
organization DisplayText,
noticeNumbers SEQUENCE OF INTEGER } DisplayText
::= CHOICE {
visibleString VisibleString (SIZE (1..200)),
bmpString BMPString (SIZE (1..200)),
utf8String UTF8String (SIZE (1..200)) } In
the given structure for CAdES-EPES signature, its is not clear that whether are
we computing the hash "SigPolicyHash" over the document at
"SPuri" and/or over the "SPUserNotice" Are
the following combinations valid? 1)
Only compute hash over document present at SPURI if only SPUri is set 2)
Only compute hash over SPUserNotice if only SPUserNotice is set 3)
Compute hash over document at SPURI and SPUserNotice if both are set Please
clarify it. Thanks! Regards, Yasir
Khan Ascertia
Ltd t.
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