A polyfill for WebCrypto that “smooths out” the rough-edges in existing User Agent implementations.
Though WebCrypto is well supported across browsers, several browsers still have prefixed and buggy implementations. Additionally, they do not always support the same algorithms, for example, Edge does not support SHA1 or ECC while both Firefox and Chrome do.
NOTE: If you are not familiar with how to use the various capabilities of WebCrypto see this great example page.
 Edge |
 Firefox |
 Chrome |
 Safari |
|---|---|---|---|
| last 2 versions | last 2 versions | last 2 versions | last 2 versions |
webcrypto-liner is a wrapper for WebCrypto designed to address these issues, at the same time it was designed to be modular so that it can also be used for testing the addition of new algorithms to WebCrypto in the future.
Intentionally webcrypto-liner does not implement any cryptography though it does consume libraries that do. We strongly recommend you read “What’s wrong with in-browser cryptography?” before using this library.
The libraries webcrypto-liner relies on include:
| Package | Description | Size | Optional |
|---|---|---|---|
| asmcrypto.js | A performant JavaScript implementation of popular cryptographic utilities with performance in mind. | 131 KB | Yes |
| elliptic | Fast Elliptic Curve Cryptography in plain javascript | 130 KB | Yes |
| webcrypto-core | A input validation layer for WebCrypto polyfills 1 | 25 KB | No |
1 This library is compiled into webcrypto-liner.
webcrypto-liner will always try to use a native implementation of webcrypto, or a prefixed version of webcrypto, before it falls back to a Javascript implementation of a given algorithm. We have no control over the corresponding implementation and what it does, for example, it may not use window.crypto.getRandomValues even if it is available and the mechanism it uses to gather randomness may be both insecure and weak.
We have done no security review or take a position on the security of these third-party libraries. YOU HAVE BEEN WARNED.
To keep webcrypto-liner as small as possible (right now it is ~11kb without dependencies) it was designed to be modular, so if you do not need ECC support, do not include elliptic as a dependency and it will not be loaded.
If you do not load any of the dependencies that provide cryptographic implementations webcrypto-liner will work as an interoperability layer, very similar to webcrypto-shim.
webcrypto-liner supports the following algorithms and key lengths:
| Capability | Details |
|---|---|
| Encryption/Decryption | RSA-OAEP, DES-CBC1, DES-EDE3-CBC1, AES-ECB 1, AES-CBC, AES-ECB and AES-GCM |
| Sign/Verify | RSA-PSS, RSASSA_PKCS1-v1_5 and ECDSA |
| Hash | SHA-1, and SHA-256, SHA-512 |
| Derive Key/Bits | ECDH, PBKDF2 |
| Keywrap | AES-GCM, AES-CBC, AES-ECB 1, DES-CBC1, DES-EDE3-CBC1 |
| ECC Curves | P-256, P-384, P-521, and K-2562 (secp256k1) |
| RSA Key Lengths | 1024, 2048, 3072, and 4096 |
| AES Key Lengths | 128, 192 and 256 |
1 Mechanism is not defined by the WebCrypto specifications. Use of mechanism in a safe way is hard, it was added for the purpose of enabling interoperability with an existing system. We recommend against its use unless needed for interoperability.
2 K-256 (secp256k1) curve is not defined by the WebCrypto specifications.
You can see the webcrypto-liner in use in the pv-webcrypto-tests page.