For "eParaksts Token Signing" functionality, a custom plugin/Extension must be installed on the end user's computer for browsers that communicate with the smart card.

End user plugin/extension installation are distributed with eParakstītājs 3.0 software package

Using the JavaScript API function getBackendInfo, it is possible to determine the state of the installed plugin/extension. In situations where the plugin/extension is not installed or its version is out of date.

JavaScript API (HWCrypto)

Components
JavaScript API (HWCrypto) consists of three files:

eparaksts-hwcrypto.js – main functions;
eparaksts-hwcrypto-legacy.js – additional functionality to provide compatibility with IE8+;
eparaksts-jquery.js – additional compatibility functions.

JavaScript API functions

getBackendInfo

Function
Returns information about end user plugin/extension

Promise window.eparakstshwcrypto.getBackendInfo()

Parameters
none

Result
Returns the Promise object that corresponds to the BackendInfo data type.

Errors
Expected errors:

technical_error.

🚧
See section JavaScript API Error Handling.

getCertificate

Function
Prompts the user to select a certificate from the list of available certificates. Connection to a browser plugin/extension that allows certificate data to be read from the user's smart card.

Promise window.eparakstshwcrypto.getCertificate(object options)

Parameters

Property		Type	Mandatory	Description
options		object	no	Conditions for certificate selection.
	lang	string	no	Preferred user interface language (ISO-639-1 code). Supported languages: en - English (default value); lv - Latvian; ru - Russian. The user interface language is not fully affected because the language used can be determined by the operating system or browser.
	operation	string	no	Type of operation: sign - document signing (signing certificate will be returned) (default value); auth - user authentication (authentication certificate will be returned)

Result
Returns the Promise object that corresponds to the Certificate data type.

Errors
Expected errors:

no_implementation;
no_certificates;
user_cancel;
technical_error.

🚧
See section JavaScript API Error Handling.

sign

Funcion
Requires the user to sign the prepared HASH value (signable data for example). Connection to a browser plugin/extension that provides signing on the user's smart card.

Promise window.eparakstshwcrypto.sign(object certificate, object hash, object options)

Parameters

Property	Object properties	Type	Mandatory	Description
certificate		object	yes	Certificate to use the corresponding private key for signing. An object corresponding to the Certificate data type was obtained using the getCertificate function.
hash		object	yes	Prepared signable HASH value
	type	string	yes	The value of the type field is not interpreted, but it is saved for backwards compatibility. In all cases it is recommended to use the constant "SHA"
	hex	string	yes	Signable HASH value in HEX encoding.* * or in case of multiple document (batch) signing, signable HASH values must be included in JSON object, which contains one or more "key:value" pairs, where: "key" - signed document identifier; "value" - Signable HASH value in HEX encoding
options		object	no	Signing conditions
	lang	string	no	Preferred user interface language (ISO-639-1 code). Supported languages: en - English (default value); lv - Latvian; The user interface language is not fully affected because the language used can be determined by the operating system or browser.
	operation	string	no	Type of operation: sign - document signing (default value); auth - user authentication
	info	string	no	Informative text (document title, transaction amount, etc.).

Result
Returns the Promise object that corresponds to the Signature data type.

Errors
Expected errors:

no_implementation;
invalid_argument;
user_cancel;
technical_error;
pin_blocked.

🚧
See section JavaScript API Error Handling.

Data Types

BackendInfo

Contains information about the end user plugin/extension installed in the browser.

Attributes

Property	Type	Description
type	string	Plugin/extension type: - NO_IMPLEMENTATION - Plugin/extension is blocked or not installed - FAILING_CHROME - Plugin/extension is not working, end user must enable plugin/extension and restart browser - FAILING_NPAPI - Plugin/extension is not working, end user must enable plugin/extension and restart browser - Plugin/extension name - Plugin/extension is working. Plugin/extension version is additionally available.
version	string	Plugin/extension version

Certificate

Contains X509 certificate data.

Attributes

Property	Type	Description
encoded	Uint8Array	The binary value of the certificate in DER encoding.
hex	string	The value of the certificate in HEX encoding. (Optional)

Signature

Contains signed data.

Attributes

Property	Type	Description
hex	string	Signed data in HEX encoding.* If request contains "JSON"* type, signed data are included in JSON object, which contains one or more "key:value" pairs, where: "key" - signed document identifier; "value" - signed data in HEX encoding. The order in which the "key:value" pairs are returned may not be identical to the order in which the signature request was built.