Basic Constraints certificate extension

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
rust
Domain
cryptography, security

Research direction

Start by locating the IsCa and BasicConstraints definitions and the certificate-extension encoding path, then compare how SelfSignedOnly and Ca(BasicConstraints) are represented. The work is done when SelfSignedOnly can explicitly encode the end-entity Basic Constraints result, with tests covering the generated extension and its absence or presence as appropriate.

Written by the indexing model from the issue text.

Description

enhancement

For Basic Constraints certificate extension currently rcgen support two options:

pub enum IsCa {
    SelfSignedOnly,
    Ca(BasicConstraints)
}

And if we look into spec we will see exactly these two options:

id-ce-basicConstraints OBJECT IDENTIFIER ::=  { id-ce 19 }

   BasicConstraints ::= SEQUENCE {
        cA                      BOOLEAN DEFAULT FALSE,
        pathLenConstraint       INTEGER (0..MAX) OPTIONAL }
and extension identifies two aspects:

Subject type: is the certificate a CA certificate or it is an end entity certificate;
[Optionally] How many CAs are allowed in the chain below current CA certificate. This setting has no meaning for end entity certificates.

And for sure Ca(x) case generate something like:

SubjectType=CA
Path length Constraint = x

But in case of SelfSignedOnly it didn't generate anything.

Empty

Despite spec said: "If Basic Constraints extension is not included in certificate, it is automatically treated as end entity certificate."

Is it possible to force writing this field?

SubjectType=End Entity
Path length Constraint = None
Dominant language
Rust
Stars
516
Forks
160
No merged PRs in 30d

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