SubtleCrypto extension type

The SubtleCrypto interface of the Web Crypto API provides a number of low-level cryptographic functions.

An instance of SubtleCrypto is available as the Crypto.subtle property of the Crypto interface, which in turn is available in windows through the Window.crypto property and in workers through the WorkerGlobalScope.crypto property.

Warning: This API provides a number of low-level cryptographic primitives. It's very easy to misuse them, and the pitfalls involved can be very subtle.

Even assuming you use the basic cryptographic functions correctly, secure key management and overall security system design are extremely hard to get right, and are generally the domain of specialist security experts.

Errors in security system design and implementation can make the security of the system completely ineffective.

Please learn and experiment, but don't guarantee or imply the security of your work before an individual knowledgeable in this subject matter thoroughly reviews it. The Crypto 101 Course can be a great place to start learning about the design and implementation of secure systems.

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API documentation sourced from MDN Web Docs.

on

• JSObject

Implemented types

• JSObject

Available extensions

• JSAnyOperatorExtension
• JSAnyUtilityExtension
• JSObjectUnsafeUtilExtension
• NullableUndefineableJSAnyExtension

Properties

hashCode → int

The hash code for this object.

no setter, inherited

isDefinedAndNotNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter

isNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

Whether this value corresponds to JavaScript null.

no setter

isTruthy → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of !!this in JavaScript.

no setter

isUndefined → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

Whether this value corresponds to JavaScript undefined.

no setter

isUndefinedOrNull → bool

Available on JSAny?, provided by the NullableUndefineableJSAnyExtension extension

no setter

not → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of !this in JavaScript.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

add(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this + any in JavaScript.

and(JSAny? any) → JSAny?

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this && any in JavaScript.

callMethod<R extends JSAny?>(JSAny method, [JSAny? arg1, JSAny? arg2, JSAny? arg3, JSAny? arg4]) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Calls method on this JSObject with up to four arguments.

callMethodVarArgs<R extends JSAny?>(JSAny method, [List<JSAny?>? arguments]) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Calls method on this JSObject with a variable number of arguments.

dartify() → Object?

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Converts a JavaScript value to the Dart equivalent if possible.

decrypt(AlgorithmIdentifier algorithm, CryptoKey key, BufferSource data) → JSPromise<JSAny?>

The decrypt() method of the SubtleCrypto interface decrypts some encrypted data. It takes as arguments a to decrypt with, some optional extra parameters, and the data to decrypt (also known as "ciphertext"). It returns a Promise which will be fulfilled with the decrypted data (also known as "plaintext").

delete(JSAny property) → JSBoolean

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Deletes the property with key property from this JSObject.

deriveBits(AlgorithmIdentifier algorithm, CryptoKey baseKey, int length) → JSPromise<JSArrayBuffer>

The deriveBits() method of the SubtleCrypto interface can be used to derive an array of bits from a base key.

deriveKey(AlgorithmIdentifier algorithm, CryptoKey baseKey, AlgorithmIdentifier derivedKeyType, bool extractable, JSArray<JSString> keyUsages) → JSPromise<JSAny?>

The deriveKey() method of the SubtleCrypto interface can be used to derive a secret key from a master key.

digest(AlgorithmIdentifier algorithm, BufferSource data) → JSPromise<JSAny?>

The digest() method of the SubtleCrypto interface generates a of the given data. A digest is a short fixed-length value derived from some variable-length input. Cryptographic digests should exhibit collision-resistance, meaning that it's hard to come up with two different inputs that have the same digest value.

divide(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this / any in JavaScript.

encrypt(AlgorithmIdentifier algorithm, CryptoKey key, BufferSource data) → JSPromise<JSAny?>

The encrypt() method of the SubtleCrypto interface encrypts data.

equals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this == any in JavaScript.

exponentiate(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this ** any in JavaScript.

exportKey(KeyFormat format, CryptoKey key) → JSPromise<JSAny?>

The exportKey() method of the SubtleCrypto interface exports a key: that is, it takes as input a CryptoKey object and gives you the key in an external, portable format.

generateKey(AlgorithmIdentifier algorithm, bool extractable, JSArray<JSString> keyUsages) → JSPromise<JSAny?>

Use the generateKey() method of the SubtleCrypto interface to generate a new key (for symmetric algorithms) or key pair (for public-key algorithms).

getProperty<R extends JSAny?>(JSAny property) → R

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

The value of the property key property of this JSObject.

greaterThan(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this > any in JavaScript.

greaterThanOrEqualTo(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this >= any in JavaScript.

has(String property) → bool

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for hasProperty to check whether this JSObject contains the property key property, but takes and returns a Dart value.

hasProperty(JSAny property) → JSBoolean

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Whether or not this JSObject contains the property key property.

importKey(KeyFormat format, JSObject keyData, AlgorithmIdentifier algorithm, bool extractable, JSArray<JSString> keyUsages) → JSPromise<CryptoKey>

The importKey() method of the SubtleCrypto interface imports a key: that is, it takes as input a key in an external, portable format and gives you a CryptoKey object that you can use in the Web Crypto API.

instanceof(JSFunction constructor) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instanceof constructor.

instanceOfString(String constructorName) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instanceof the constructor that is defined by constructorName, which is looked up in the globalContext.

isA<T extends JSAny?>() → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether this JSAny? is an instance of the JavaScript type that is declared by T.

lessThan(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this < any in JavaScript.

lessThanOrEqualTo(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this <= any in JavaScript.

modulo(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this % any in JavaScript.

multiply(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this * any in JavaScript.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

notEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this != any in JavaScript.

or(JSAny? any) → JSAny?

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this || any in JavaScript.

setProperty(JSAny property, JSAny? value) → void

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Write the value of property key property of this JSObject.

sign(AlgorithmIdentifier algorithm, CryptoKey key, BufferSource data) → JSPromise<JSAny?>

The sign() method of the SubtleCrypto interface generates a digital .

strictEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this === any in JavaScript.

strictNotEquals(JSAny? any) → JSBoolean

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this !== any in JavaScript.

subtract(JSAny? any) → JSAny

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this - any in JavaScript.

toString() → String

A string representation of this object.

inherited

typeofEquals(String typeString) → bool

Available on JSAny?, provided by the JSAnyUtilityExtension extension

Whether the result of typeof on this JSAny? is typeString.

unsignedRightShift(JSAny? any) → JSNumber

Available on JSAny?, provided by the JSAnyOperatorExtension extension

The result of this >>> any in JavaScript.

unwrapKey(KeyFormat format, BufferSource wrappedKey, CryptoKey unwrappingKey, AlgorithmIdentifier unwrapAlgorithm, AlgorithmIdentifier unwrappedKeyAlgorithm, bool extractable, JSArray<JSString> keyUsages) → JSPromise<CryptoKey>

The unwrapKey() method of the SubtleCrypto interface "unwraps" a key. This means that it takes as its input a key that has been exported and then encrypted (also called "wrapped"). It decrypts the key and then imports it, returning a CryptoKey object that can be used in the Web Crypto API.

verify(AlgorithmIdentifier algorithm, CryptoKey key, BufferSource signature, BufferSource data) → JSPromise<JSAny?>

The verify() method of the SubtleCrypto interface verifies a digital .

wrapKey(KeyFormat format, CryptoKey key, CryptoKey wrappingKey, AlgorithmIdentifier wrapAlgorithm) → JSPromise<JSAny?>

The wrapKey() method of the SubtleCrypto interface "wraps" a key. This means that it exports the key in an external, portable format, then encrypts the exported key. Wrapping a key helps protect it in untrusted environments, such as inside an otherwise unprotected data store or in transmission over an unprotected network.

Operators

operator ==(Object other) → bool

The equality operator.

inherited

operator [](String property) → JSAny?

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for getProperty to get the value of the property key property of this JSObject, but takes and returns a Dart value.

operator []=(String property, JSAny? value) → void

Available on JSObject, provided by the JSObjectUnsafeUtilExtension extension

Shorthand helper for setProperty to write the value of the property key property of this JSObject, but takes a Dart value.