Web/API/SubtleCrypto

From Get docs

Secure contextThis feature is available only in secure contexts (HTTPS), in some or all supporting browsers.


The SubtleCrypto interface of the Web Crypto API provides a number of low-level cryptographic functions. Access to the features of SubtleCrypto is obtained through the subtle property of the Crypto object you get from Window.crypto.

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.

If you're not sure you know what you are doing, you probably shouldn't be using this API.


Properties

This interface doesn't inherit any properties, as it has no parent interface.

Methods

This interface doesn't inherit any methods, as it has no parent interface.

SubtleCrypto.encrypt()
Returns a Promise that fufills with the encrypted data corresponding to the clear text, algorithm, and key given as parameters.
SubtleCrypto.decrypt()
Returns a Promise that fulfills with the clear data corresponding to the encrypted text, algorithm, and key given as parameters.
SubtleCrypto.sign()
Returns a Promise that fulfills with the signature corresponding to the text, algorithm, and key given as parameters.
SubtleCrypto.verify()
Returns a Promise that fulfills with a Boolean value indicating if the signature given as a parameter matches the text, algorithm, and key that are also given as parameters.
SubtleCrypto.digest()
Returns a Promise that fulfills with a digest generated from the algorithm and text given as parameters.
SubtleCrypto.generateKey()
Returns a Promise that fulfills with a newly-generated CryptoKey, for symmetrical algorithms, or a CryptoKeyPair, containing two newly generated keys, for asymmetrical algorithms. These will match the algorithm, usages, and extractability given as parameters.
SubtleCrypto.deriveKey()
Returns a Promise that fulfills with a newly generated CryptoKey derived from the master key and specific algorithm given as parameters.
SubtleCrypto.deriveBits()
Returns a Promise that fulfills with a newly generated buffer of pseudo-random bits derived from the master key and specific algorithm given as parameters.
SubtleCrypto.importKey()
Returns a Promise that fulfills with a CryptoKey corresponding to the format, the algorithm, raw key data, usages, and extractability given as parameters.
SubtleCrypto.exportKey()
Returns a Promise that fulfills with a buffer containing the key in the requested format.
SubtleCrypto.wrapKey()
Returns a Promise that fulfills with a wrapped symmetric key for usage (transfer and storage) in insecure environments. The wrapped key matches the format specified in the given parameters, and wrapping is done by the given wrapping key, using the specified algorithm.
SubtleCrypto.unwrapKey()
Returns a Promise that fulfills with a CryptoKey corresponding to the wrapped key given in the parameter.

Using SubtleCrypto

We can split the functions implemented by this API into two groups: cryptography functions and key management functions.

Cryptography functions

These are the functions you can use to implement security features such as privacy and authentication in a system. The SubtleCrypto API provides the following cryptography functions:

Key management functions

Except for digest(), all the cryptography functions in the API use cryptographic keys. In the SubtleCrypto API a cryptographic key is represented using a CryptoKey object. To perform operations like signing and encrypting, you pass a CryptoKey object into the sign() or encrypt() function.

Generating and deriving keys

The generateKey() and deriveKey() functions both create a new CryptoKey object.

The difference is that generateKey() will generate a new distinct key value each time you call it, while deriveKey() derives a key from some initial keying material. If you provide the same keying material to two separate calls to deriveKey(), you will get two CryptoKey objects that have the same underlying value. This is useful if, for example, you want to derive an encryption key from a password and later derive the same key from the same password to decrypt the data.

Importing and exporting keys

To make keys available outside your app, you need to export the key, and that's what exportKey() is for. You can choose one of a number of export formats.

The inverse of exportKey() is importKey(). You can import keys from other systems, and support for standard formats like PKCS #8 and JSON Web Key helps you do this. The exportKey() function exports the key in an unencrypted format.

If the key is sensitive you should use wrapKey(), which exports the key and then encrypts it using another key; the API calls a "key-wrapping key".

The inverse of wrapKey() is unwrapKey(), which decrypts then imports the key.

Storing keys

CryptoKey objects can be stored using the structured clone algorithm, meaning that you can store and retrieve them using standard web storage APIs. The specification expects that most developers will use the IndexedDB API to store CryptoKey objects.

Supported algorithms

The cryptographic functions provided by the Web Crypto API can be performed by one or more different cryptographic algorithms: the algorithm argument to the function indicates which algorithm to use. Some algorithms need extra parameters: in these cases the algorithm argument is a dictionary object that includes the extra parameters.

The table below summarises which algorithms are suitable for which cryptographic operations:

sign()

verify()

encrypt()

decrypt()

digest()

deriveBits()

deriveKey()

wrapKey()

unwrapKey()

RSASSA-PKCS1-v1_5
RSA-PSS
ECDSA
HMAC
RSA-OAEP
AES-CTR
AES-CBC
AES-GCM
SHA-1
SHA-256
SHA-384
SHA-512
ECDH
HKDF
PBKDF2
AES-KW

Specifications

Specification Status Comment
Web Cryptography APIThe definition of 'SubtleCrypto' in that specification. Recommendation Initial definition.

Browser compatibility

Update compatibility data on GitHub

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
SubtleCrypto Chrome

Full support 37

Edge

Partial support 12

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE

Partial support 11

Opera

Full support 24

Safari Full support 10.1


Full support 10.1


Full support 7

Prefixed'

Prefixed' Implemented with the vendor prefix: WebKit

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS Full support 10.3


Full support 10.3


Full support 7

Prefixed'

Prefixed' Implemented with the vendor prefix: WebKit

Samsung Internet Android

Full support 6.0

decrypt Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: AES-CTR.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns CryptoOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

deriveBits Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: ECDH. Notes' Not supported: HKDF, PBKDF2.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE

No support No

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

deriveKey Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: ECDH. Notes' Not supported: HKDF, PBKDF2.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE

No support No

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

digest Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: SHA-1.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns CryptoOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

encrypt Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: AES-CTR.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns CryptoOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

exportKey Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: RSA-PSS, ECDSA, ECDH. Notes' Not supported: AES-CTR.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns KeyOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

generateKey Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: RSA-PSS, ECDSA, ECDH. Notes' Not supported: AES-CTR.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns KeyOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

importKey Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: RSA-PSS, ECDSA, ECDH. Notes' Not supported: AES-CTR, HKDF, PBKDF2.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns KeyOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

Secure context required Chrome

Full support 60

Edge

Full support 79

Firefox

Full support 75

IE

No support No

Opera

Full support 47

Safari

No support No

WebView Android

Full support 60

Chrome Android

Full support 60

Firefox Android

No support No

Opera Android

Full support 47

Safari iOS

No support No

Samsung Internet Android

Full support 8.0

sign Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: RSA-PSS, ECDSA.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns CryptoOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

unwrapKey Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: AES-CTR.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns KeyOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

?

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

verify Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: RSA-PSS, ECDSA.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns CryptoOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

Available in workers Chrome

?

Edge

?

Firefox

Full support 48

IE

?

Opera

?

Safari

?

WebView Android

?

Chrome Android

?

Firefox Android

?

Opera Android

?

Safari iOS

?

Samsung Internet Android

?

wrapKey Chrome

Full support 37

Edge Partial support 12

Notes'

Partial support 12

Notes'

Notes' Not supported: AES-CTR.

Firefox Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

IE Partial support 11

Notes'

Partial support 11

Notes'

Notes' Returns KeyOperation instead of Promise

Opera

Full support 24

Safari

Full support 7

WebView Android

Full support 37

Chrome Android

Full support 37

Firefox Android Full support 34


Full support 34


No support 32 — 34

Disabled'

Disabled' From version 32 until version 34 (exclusive): this feature is behind the dom.webcrypto.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

Opera Android

Full support 24

Safari iOS

Full support 7

Samsung Internet Android

Full support 6.0

Legend

Full support  
Full support
Partial support  
Partial support
No support  
No support
Compatibility unknown  
Compatibility unknown
See implementation notes.'
See implementation notes.
User must explicitly enable this feature.'
User must explicitly enable this feature.
Requires a vendor prefix or different name for use.'
Requires a vendor prefix or different name for use.


See also