SecureString React Native Reference Documentation

SecureString

Current Version: 11.6.1

Chilkat.SecureString

Store, append, compare, hash, verify, and securely access sensitive string values.

Chilkat.SecureString holds sensitive text in an encrypted in-memory form while still allowing controlled operations on the value. It can append clear-text strings, append text from a StringBuilder, append another SecureString, load text from a file, return the clear-text value when needed, compare secure strings, mark the value read-only, maintain a hash of the current value, and verify a supplied hash against that maintained value.

Encrypted in-memory value

Store sensitive text in a form that is decrypted only when needed for access, modification, comparison, or hashing.

Append safely

Append clear-text strings, StringBuilder content, or another SecureString; the value is then re-encrypted.

Read-only protection

Set ReadOnly to prevent later modification of the secure string.

Hash maintenance

Set MaintainHash to a supported hash algorithm such as sha256, sha512, sha1, or md5.

Hash output and verification

Retrieve the current hash value in an encoding such as hex or Base64, or verify a supplied encoded hash with VerifyHash.

Compare and access

Compare two secure strings with SecStrEquals, or call Access when the clear-text value is required.

Common pattern: Create a SecureString, load or append the sensitive text, set MaintainHash if later verification is needed, and optionally set ReadOnly after the final value is established. Use Access only at the point where the clear-text string is actually needed, and check LastErrorText if an append, file load, hash, or verification operation fails.

Hash note: VerifyHash depends on MaintainHash having already been set so the object maintains an internal hash for the current secure string value.

Object Creation

// npm install @chilkat/react-native react-native-nitro-modules
// (React Native 0.76+ with the New Architecture; then `pod install` for iOS.  The Chilkat
//  native library is downloaded and verified during the native build -- see the package README.)

import { Chilkat, SecureString } from '@chilkat/react-native'

// Once per app start, before any other Chilkat call:
Chilkat.unlockBundle('Anything for 30-day trial')   // shorthand for new Global().unlockBundle(..)

const secureString = new SecureString()
// ... the native object is released when `secureString` is garbage collected, or now with secureString.dispose()

new SecureString()

Creates the underlying native Chilkat object. SecureString is a Nitro Module HybridObject: use it from the JavaScript thread only (it cannot be passed to a Worklet or another runtime). Every member is synchronous and blocks the JavaScript thread until Chilkat returns; a method that can take a while also exists as a ...Async twin returning a Promise, which runs the same call on a native worker thread so the UI keeps rendering. While such a call is pending, every other call on this object throws, except abort() and assigning onPercentDone / onProgressInfo.

dispose(): void

Releases the native object immediately instead of waiting for garbage collection (useful for a large BinData or an open socket). Calling it more than once is harmless; any other use of the object afterwards throws. An object with a pending ...Async call cannot be disposed until the promise settles.

Errors

A method that can fail throws a plain Error: a method whose only outcome is success or failure returns void and throws on failure; a method producing a string or an object returns it and throws where Chilkat would have returned null. The error's message is "Class.method(...): reason", where the reason is the last informative line of the object's lastErrorText, which holds the full Chilkat log of the failed call. A ...Async twin rejects its promise with the same Error instead of throwing. Properties never throw, and methods that answer a question (has..., is..., ...) return a plain boolean.

try {
  secureString.someMethod(...)
} catch (e) {
  console.log((e as Error).message)   // SecureString.someMethod(...): <reason>
  console.log(secureString.lastErrorText)   // the full Chilkat log of the failed call
}

// The same call without blocking the JavaScript thread:
try {
  await secureString.someMethodAsync(...)
} catch (e) {
  console.log((e as Error).message)   // SecureString.someMethodAsync: <reason>
}

Properties

DebugLogFilePath

// read/write
debugLogFilePath: string

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

SecureString React Native Reference Documentation

SecureString

Current Version: 11.6.1

Store, append, compare, hash, verify, and securely access sensitive string values.

Encrypted in-memory value

Append safely

Read-only protection

Hash maintenance

Hash output and verification

Compare and access

Object Creation

Errors

Properties

DebugLogFilePath

LastErrorHtml

LastErrorText

LastErrorXml

LastMethodSuccess

MaintainHash

ReadOnly

VerboseLogging

Version

Methods

Access

Append

AppendSb

AppendSecure

HashVal

LoadFile

SecStrEquals

VerifyHash