chrome.certificateProvider

Description

Use this API to expose certificates to the platform which can use these certificates for TLS authentications.

Permissions

certificateProvider

Availability

Chrome 46+ ChromeOS only

Concepts and usage

Typical usage of this API to expose client certificates to ChromeOS follows these steps:

  • The Extension registers for the events onCertificatesUpdateRequested and onSignatureRequested.
  • The Extension calls setCertificates() to provide the initial list of certificates after the initialization.
  • The Extension monitors the changes in the list of available certificates and calls setCertificates() to notify the browser about every such change.
  • During a TLS handshake, the browser receives a client certificate request. With an onCertificatesUpdateRequested event, the browser asks the Extension to report all certificates that it currently provides.
  • The Extension reports back with the currently available certificates, using the setCertificates() method.
  • The browser matches all available certificates with the client certificate request from the remote host. The matches are presented to the user in a selection dialog.
  • The user can select a certificate and thereby approve the authentication or abort the authentication.
Certificate selection dialog
Certificate selection dialog.
  • If the user aborts the authentication or no certificate matched the request, the TLS client authentication is aborted.
  • Otherwise, if the user approves the authentication with a certificate provided by this Extension, the browser requests the Extension to sign the data to continue the TLS handshake. The request is sent as a onSignatureRequested event.
  • This event contains input data, declares which algorithm has to be used to generate the signature, and refers to one of the certificates that were reported by this Extension. The Extension must create a signature for the given data using the private key associated with the referenced certificate. Creating the signature might require prepending a DigestInfo and padding the result before the actual signing.
  • The Extension sends back the signature to the browser using the reportSignature() method. If the signature couldn't be calculated, the method has to be called without signature.
  • If the signature was provided, the browser completes the TLS handshake.

The actual sequence of steps can be different. For example, the user will not be asked to select a certificate if the enterprise policy to automatically select a certificate is used (see AutoSelectCertificateForUrls and Chrome policies for users).

In the Extension, this can look similar to the following snippet:

function collectAvailableCertificates() {
  // Return all certificates that this Extension can currently provide.
  // For example:
  return [{
    certificateChain: [new Uint8Array(...)],
    supportedAlgorithms: ['RSASSA_PKCS1_v1_5_SHA256']
  }];
}

// The Extension calls this function every time the currently available list of
// certificates changes, and also once after the Extension's initialization.
function onAvailableCertificatesChanged() {
  chrome.certificateProvider.setCertificates({
    clientCertificates: collectAvailableCertificates()
  });
}

function handleCertificatesUpdateRequest(request) {
  // Report the currently available certificates as a response to the request
  // event. This is important for supporting the case when the Extension is
  // unable to detect the changes proactively.
  chrome.certificateProvider.setCertificates({
    certificatesRequestId: request.certificatesRequestId,
    clientCertificates: collectAvailableCertificates()
  });
}

// Returns a private key handle for the given DER-encoded certificate.
// |certificate| is an ArrayBuffer.
function getPrivateKeyHandle(certificate) {...}

// Digests and signs |input| with the given private key. |input| is an
// ArrayBuffer. |algorithm| is an Algorithm.
// Returns the signature as ArrayBuffer.
function signUnhashedData(privateKey, input, algorithm) {...}

function handleSignatureRequest(request) {
  // Look up the handle to the private key of |request.certificate|.
  const key = getPrivateKeyHandle(request.certificate);
  if (!key) {
    // Handle if the key isn't available.
    console.error('Key for requested certificate no available.');

    // Abort the request by reporting the error to the API.
    chrome.certificateProvider.reportSignature({
      signRequestId: request.signRequestId,
      error: 'GENERAL_ERROR'
    });
    return;
  }

  const signature = signUnhashedData(key, request.input, request.algorithm);
  chrome.certificateProvider.reportSignature({
    signRequestId: request.signRequestId,
    signature: signature
  });
}

chrome.certificateProvider.onCertificatesUpdateRequested.addListener(
    handleCertificatesUpdateRequest);
chrome.certificateProvider.onSignatureRequested.addListener(
    handleSignatureRequest);

Types

Algorithm

Chrome 86+

Types of supported cryptographic signature algorithms.

Enum

"RSASSA_PKCS1_v1_5_MD5_SHA1"
Specifies the RSASSA PKCS#1 v1.5 signature algorithm with the MD5-SHA-1 hashing. The extension must not prepend a DigestInfo prefix but only add PKCS#1 padding. This algorithm is deprecated and will never be requested by Chrome as of version 109.

"RSASSA_PKCS1_v1_5_SHA1"
Specifies the RSASSA PKCS#1 v1.5 signature algorithm with the SHA-1 hash function.

"RSASSA_PKCS1_v1_5_SHA256"
Specifies the RSASSA PKCS#1 v1.5 signature algorithm with the SHA-256 hashing function.

"RSASSA_PKCS1_v1_5_SHA384"
Specifies the RSASSA PKCS#1 v1.5 signature algorithm with the SHA-384 hashing function.

"RSASSA_PKCS1_v1_5_SHA512"
Specifies the RSASSA PKCS#1 v1.5 signature algorithm with the SHA-512 hashing function.

"RSASSA_PSS_SHA256"
Specifies the RSASSA PSS signature algorithm with the SHA-256 hashing function, MGF1 mask generation function and the salt of the same size as the hash.

"RSASSA_PSS_SHA384"
Specifies the RSASSA PSS signature algorithm with the SHA-384 hashing function, MGF1 mask generation function and the salt of the same size as the hash.

"RSASSA_PSS_SHA512"
Specifies the RSASSA PSS signature algorithm with the SHA-512 hashing function, MGF1 mask generation function and the salt of the same size as the hash.

CertificateInfo

Properties

  • certificate

    ArrayBuffer

    Must be the DER encoding of a X.509 certificate. Currently, only certificates of RSA keys are supported.

  • supportedHashes

    Hash[]

    Must be set to all hashes supported for this certificate. This extension will only be asked for signatures of digests calculated with one of these hash algorithms. This should be in order of decreasing hash preference.

CertificatesUpdateRequest

Chrome 86+

Properties

  • certificatesRequestId

    number

    Request identifier to be passed to setCertificates.

ClientCertificateInfo

Chrome 86+

Properties

  • certificateChain

    ArrayBuffer[]

    The array must contain the DER encoding of the X.509 client certificate as its first element.

    This must include exactly one certificate.

  • supportedAlgorithms

    Algorithm[]

    All algorithms supported for this certificate. The extension will only be asked for signatures using one of these algorithms.

Error

Chrome 86+

Types of errors that the extension can report.

Value

"GENERAL_ERROR"

Hash

Deprecated. Replaced by Algorithm.

Enum

"MD5_SHA1"
Specifies the MD5 and SHA1 hashing algorithms.

"SHA1"
Specifies the SHA1 hashing algorithm.

"SHA256"
Specifies the SHA256 hashing algorithm.

"SHA384"
Specifies the SHA384 hashing algorithm.

"SHA512"
Specifies the SHA512 hashing algorithm.

PinRequestErrorType

Chrome 57+

The types of errors that can be presented to the user through the requestPin function.

Enum

"INVALID_PIN"
Specifies the PIN is invalid.

"INVALID_PUK"
Specifies the PUK is invalid.

"MAX_ATTEMPTS_EXCEEDED"
Specifies the maximum attempt number has been exceeded.

"UNKNOWN_ERROR"
Specifies that the error cannot be represented by the above types.

PinRequestType

Chrome 57+

The type of code being requested by the extension with requestPin function.

Enum

"PIN"
Specifies the requested code is a PIN.

"PUK"
Specifies the requested code is a PUK.

PinResponseDetails

Chrome 57+

Properties

  • userInput

    string optional

    The code provided by the user. Empty if user closed the dialog or some other error occurred.

ReportSignatureDetails

Chrome 86+

Properties

  • error

    "GENERAL_ERROR"
     optional

    Error that occurred while generating the signature, if any.

  • signRequestId

    number

    Request identifier that was received via the onSignatureRequested event.

  • signature

    ArrayBuffer optional

    The signature, if successfully generated.

RequestPinDetails

Chrome 57+

Properties

  • attemptsLeft

    number optional

    The number of attempts left. This is provided so that any UI can present this information to the user. Chrome is not expected to enforce this, instead stopPinRequest should be called by the extension with errorType = MAX_ATTEMPTS_EXCEEDED when the number of pin requests is exceeded.

  • errorType

    PinRequestErrorType optional

    The error template displayed to the user. This should be set if the previous request failed, to notify the user of the failure reason.

  • requestType

    PinRequestType optional

    The type of code requested. Default is PIN.

  • signRequestId

    number

    The ID given by Chrome in SignRequest.

SetCertificatesDetails

Chrome 86+

Properties

  • certificatesRequestId

    number optional

    When called in response to onCertificatesUpdateRequested, should contain the received certificatesRequestId value. Otherwise, should be unset.

  • clientCertificates

    ClientCertificateInfo[]

    List of currently available client certificates.

  • error

    "GENERAL_ERROR"
     optional

    Error that occurred while extracting the certificates, if any. This error will be surfaced to the user when appropriate.

SignatureRequest

Chrome 86+

Properties

  • algorithm

    Algorithm

    Signature algorithm to be used.

  • certificate

    ArrayBuffer

    The DER encoding of a X.509 certificate. The extension must sign input using the associated private key.

  • input

    ArrayBuffer

    Data to be signed. Note that the data is not hashed.

  • signRequestId

    number

    Request identifier to be passed to reportSignature.

SignRequest

Properties

  • certificate

    ArrayBuffer

    The DER encoding of a X.509 certificate. The extension must sign digest using the associated private key.

  • digest

    ArrayBuffer

    The digest that must be signed.

  • hash

    Hash

    Refers to the hash algorithm that was used to create digest.

  • signRequestId

    number

    Chrome 57+

    The unique ID to be used by the extension should it need to call a method that requires it, e.g. requestPin.

StopPinRequestDetails

Chrome 57+

Properties

  • errorType

    PinRequestErrorType optional

    The error template. If present it is displayed to user. Intended to contain the reason for stopping the flow if it was caused by an error, e.g. MAX_ATTEMPTS_EXCEEDED.

  • signRequestId

    number

    The ID given by Chrome in SignRequest.

Methods

reportSignature()

Promise Chrome 86+ 
chrome.certificateProvider.reportSignature(
  details: ReportSignatureDetails,
  callback?: function,
)

Should be called as a response to onSignatureRequested.

The extension must eventually call this function for every onSignatureRequested event; the API implementation will stop waiting for this call after some time and respond with a timeout error when this function is called.

Parameters

Returns

  • Promise<void>

    Chrome 96+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

requestPin()

Promise Chrome 57+ 
chrome.certificateProvider.requestPin(
  details: RequestPinDetails,
  callback?: function,
)

Requests the PIN from the user. Only one ongoing request at a time is allowed. The requests issued while another flow is ongoing are rejected. It's the extension's responsibility to try again later if another flow is in progress.

Parameters

Returns

  • Promise<PinResponseDetails | undefined>

    Chrome 96+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

setCertificates()

Promise Chrome 86+ 
chrome.certificateProvider.setCertificates(
  details: SetCertificatesDetails,
  callback?: function,
)

Sets a list of certificates to use in the browser.

The extension should call this function after initialization and on every change in the set of currently available certificates. The extension should also call this function in response to onCertificatesUpdateRequested every time this event is received.

Parameters

  • The certificates to set. Invalid certificates will be ignored.

  • callback

    function optional

    The callback parameter looks like: 

    () => void

Returns

  • Promise<void>

    Chrome 96+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

stopPinRequest()

Promise Chrome 57+ 
chrome.certificateProvider.stopPinRequest(
  details: StopPinRequestDetails,
  callback?: function,
)

Stops the pin request started by the requestPin function.

Parameters

  • Contains the details about the reason for stopping the request flow.

  • callback

    function optional

    The callback parameter looks like: 

    () => void

Returns

  • Promise<void>

    Chrome 96+

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

Events

onCertificatesUpdateRequested

Chrome 86+ 
chrome.certificateProvider.onCertificatesUpdateRequested.addListener(
  callback: function,
)

This event fires if the certificates set via setCertificates are insufficient or the browser requests updated information. The extension must call setCertificates with the updated list of certificates and the received certificatesRequestId.

Parameters

onSignatureRequested

Chrome 86+ 
chrome.certificateProvider.onSignatureRequested.addListener(
  callback: function,
)

This event fires every time the browser needs to sign a message using a certificate provided by this extension via setCertificates.

The extension must sign the input data from request using the appropriate algorithm and private key and return it by calling reportSignature with the received signRequestId.

Parameters