CertChain Rust Reference Documentation

CertChain

Current Version: 11.6.1

Chilkat.CertChain

Inspect, verify, export, and work with X.509 certificate chains.

Chilkat.CertChain is a compact helper class for representing and working with X.509 certificate chains. It lets applications inspect the ordered certificates in a chain, retrieve individual certificates, determine whether the chain reaches a root, check for expired certificates, verify chain signatures, test whether the root is trusted, load certificate chains from JWK x5c data, and export the chain as X509PKIPathv1.

Chain inspection

Examine the certificates in chain order and retrieve individual certificates with CertAt.

Root and trust checks

Determine whether the chain reaches a root certificate and whether that root is trusted.

Signature verification

Verify that each certificate in the chain is signed by the next certificate in the chain.

Expiration checks

Detect whether one or more certificates in the chain are expired.

JWK x5c support

Load certificate chains from JWK x5c arrays used by JWT, JWS, and other security-token workflows.

Chain export

Export the certificate chain in X509PKIPathv1 format when that representation is required.

Common pattern: Use CertChain to reason about the chain as a whole. For certificate-level details such as subject, issuer, SAN values, key usage, validity dates, fingerprints, serial numbers, and extensions, retrieve each certificate with CertAt and inspect it using Chilkat.Cert.

For an extended overview, see CertChain Class Overview.

Object Creation

// Cargo.toml:
//     [dependencies]
//     chilkat = "11.6"

use chilkat::CertChain;

// Once per process, before any other Chilkat call:
chilkat::unlock_bundle("Anything for 30-day trial")?;  // shorthand for Global::new().unlock_bundle(..)

let cert_chain = CertChain::new();
// ... the native object is freed when `cert_chain` goes out of scope.
pub fn new() -> CertChain

Creates the underlying native Chilkat object (CertChain also implements Default). Every method takes &self, so the object never needs to be declared mut. A CertChain is Send but not Sync: it may be moved to another thread, but a reference to it cannot be shared between threads at the same time.

impl Drop for CertChain

The native object is freed when the CertChain is dropped — when it goes out of scope, or explicitly with drop(cert_chain). There is no Dispose method to call.

Errors

Methods that can fail return chilkat::Result<T>, which is Result<T, chilkat::Error>: a method whose only outcome is success or failure returns Result<()>, a method producing a string or an object returns Result<String> or Result<CertChain>. The error carries the object's LastErrorText at the time of the failure (Error::last_error_text), the class and method names, and implements std::error::Error, so ? works in any function returning chilkat::Result or a Box<dyn Error>. Properties never fail, and methods that answer a question (has_..., is_..., ...) return a plain bool.

match cert_chain.some_method(...) {
    Ok(value) => println!("{value:?}"),
    Err(e) => eprintln!("{}", e.last_error_text()),
}

Properties

DebugLogFilePath
// read/write
pub fn debug_log_file_path(&self) -> String
pub fn set_debug_log_file_path(&self, value: &str)

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
Example showing how to use DebugLogFilePath.
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LastErrorHtml
// read-only
pub fn last_error_html(&self) -> String

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
// read-only
pub fn last_error_text(&self) -> String

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

More Information and Examples
Concept of LastErrorTextLastErrorText Standard Information
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LastErrorXml
// read-only
pub fn last_error_xml(&self) -> String

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastMethodSuccess
// read/write
pub fn last_method_success(&self) -> bool
pub fn set_last_method_success(&self, value: bool)

Indicates the success or failure of the most recent method call: true means success, false means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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NumCerts
// read-only
pub fn num_certs(&self) -> i32
Introduced in version 9.5.0.40

The number of certificates currently contained in the chain.

Index Meaning
0 The target or end-entity certificate—the certificate farthest from the root end of the chain
1 ... NumCerts - 2 Intermediate CA certificates, when present
NumCerts - 1 The highest certificate available in the chain
Do not assume the final certificate is trusted: If ReachesRoot is false, the final certificate may only be the highest intermediate that was available. Even when the chain ends in a self-signed root, trust must be established separately.

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NumExpiredCerts
// read-only
pub fn num_expired_certs(&self) -> i32
Introduced in version 9.5.0.40

The number of certificates in the chain whose validity period has expired.

Expiration is only one validation check: A value of 0 does not mean the chain is valid or trusted. It does not by itself establish that certificates are already valid, correctly signed, unrevoked, issued by an accepted trust anchor, or suitable for the intended identity and key usage.

Retrieve individual certificates with CertAt when the application needs to inspect exact validity dates or identify which certificates are expired.

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ReachesRoot
// read-only
pub fn reaches_root(&self) -> bool
Introduced in version 9.5.0.44

true if the chain extends to a terminal root certificate rather than stopping at an intermediate certificate. When this property is true, the certificate at index NumCerts - 1 is the root-end certificate of the chain.

Root presence is not root trust: An included root is commonly self-signed, but its presence does not make it a trusted anchor. Use IsRootTrusted with the application's approved TrustedRoots collection to test trust-anchor membership.

A value of false means the chain is incomplete at the root end; the final certificate may be an intermediate CA for which no issuer certificate was available.

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UncommonOptions
// read/write
pub fn uncommon_options(&self) -> String
pub fn set_uncommon_options(&self, value: &str)
Introduced in version 9.5.0.98

Specifies uncommon behavior as a comma-separated list of keywords. The default is the empty string, which enables the standard behavior.

Keyword Effect
PkiPathV1.ExcludeRoot Omits the root certificate from the value returned by X509PKIPathv1. This option affects that method only.
Interoperability note: Some protocols transport the trust anchor with the path, while others expect the recipient to obtain or trust it independently. Use this option according to the format required by the receiving system.

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VerboseLogging
// read/write
pub fn verbose_logging(&self) -> bool
pub fn set_verbose_logging(&self, value: bool)

If set to true, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is false. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
// read-only
pub fn version(&self) -> String

Version of the component/library, such as "10.1.0"

More Information and Examples
How to get the Chilkat version at runtime.
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Methods

CertAt
pub fn cert_at(&self, index: i32, cert: &Cert) -> Result<()>
Introduced in version 11.0.0

Populates cert with the certificate at the specified zero-based index. Valid indices range from 0 through NumCerts - 1.

Index Position in the chain
0 Target or end-entity certificate
1 ... NumCerts - 2 Intermediate CA certificates, when present
NumCerts - 1 Highest certificate available in the chain; a root certificate only when ReachesRoot is true

Returns true on success. Returns false if the index is invalid or the certificate cannot be returned; in that case, do not use the contents of cert as a successful result.

Returns Ok(()) for success, Err(chilkat::Error) for failure.

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IsRootTrusted
pub fn is_root_trusted(&self, trusted_roots: &TrustedRoots) -> bool
Introduced in version 9.5.0.40

Tests whether the certificate at the root end of this chain is present in the TrustedRoots collection passed in trusted_roots. Returns true when a matching trusted-root certificate is found; otherwise returns false.

Trust is a local policy decision: A self-signed certificate is not trusted merely because it appears at the end of a chain. This method checks membership in the supplied trust collection; it does not, by itself, establish that the entire chain is valid for a particular application or identity.

A complete certificate-validation decision may also require checking signature linkage, certificate validity periods, revocation status, basic constraints, key usage, policies, name constraints, and application-specific identity requirements.

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LoadX5C
pub fn load_x5_c(&self, jwk: &JsonObject) -> Result<()>
Introduced in version 9.5.0.66

Loads the certificate chain from the x5c member of the JWK contained in jwk. Returns true if the chain is loaded successfully; otherwise returns false.

As defined by RFC 7517, x5c is a JSON array of DER-encoded X.509 certificates represented using standard Base64—not Base64URL. The first certificate contains the key associated with the JWK. Each following certificate should certify the certificate immediately before it, so the array order is target certificate first and rootward certificates afterward.

Security note: Loading an x5c array does not make its certificates trusted. Treat the chain as untrusted input until the required signature, validity, trust-anchor, revocation, and application-policy checks have been completed.

Returns Ok(()) for success, Err(chilkat::Error) for failure.

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VerifyCertSignatures
pub fn verify_cert_signatures(&self) -> bool
Introduced in version 9.5.0.40

Verifies the cryptographic signature linkage of the certificates in this chain. Starting with the target certificate at index 0, each certificate's signature is checked using the public key of the next issuer certificate in the chain. Returns true when the certificate signatures are valid through the root end of the chain; otherwise returns false.

Signature verification is not full path validation: A true result confirms the issuer-signature relationships represented by the chain. It does not by itself prove that the root is trusted, that certificates are within their validity periods, that none are revoked, that CA constraints and policies are acceptable, or that the target certificate is valid for a particular hostname or usage.
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X509PKIPathv1
pub fn x509_pki_pathv1(&self) -> Result<String>
Introduced in version 9.5.0.88

Returns the Base64 representation of a DER-encoded ASN.1 PkiPath containing the certificates in this chain. This representation is commonly identified as the X509PKIPathv1 token type in WS-Security and may also be encountered in XML-signature workflows.

A PkiPath is a SEQUENCE OF Certificate ordered from the root or most-trusted end toward the target certificate. This is the reverse of the indexing used by CertAt, where index 0 is the target certificate.

Representation Certificate order
CertChain indexing Target/leaf → intermediates → root
X509PKIPathv1 Root → intermediates → target/leaf

By default, the root certificate is included when it is present in the chain. Set UncommonOptions to PkiPathV1.ExcludeRoot when the receiving protocol expects the trust anchor to be supplied separately.

Return-value note: This is a string-returning method. Check LastMethodSuccess before using the returned text, and inspect LastErrorText if the operation fails.

Returns Err(chilkat::Error) on failure.

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