Feature/2 ecdsa implementation

README.md

@@ -2,12 +2,18 @@
 
 An implementation of the W3C Web Cryptography API specification (https://www.w3.org/TR/WebCryptoAPI/) for Go using Go's standard `crypto` library.
 
+> [!IMPORTANT]  
+> Whilst we try to ensure that we don't commit breaking changes until we release our first stable version, there
+> may be times where decisions made during early development no longer make sense and therefore require
+> breaking changes. Please be mindful of this when updating your version of this library until we hit v1.0.0.
+
 ## Contents
 
 - [Background](#background)
 - [Implementation status](#implementation-status)
 - [Getting started](#getting-started)
 - [Algorithms](#algorithms)
+	- [ECDSA](#ecdsa)
 	- [HMAC](#hmac)
 	- [RSA-OAEP](#rsa-oaep)
 	- [SHA](#sha)
@@ -29,6 +35,7 @@ This library is still in active development and all algorithms are not yet suppo
 
 | Algorithm | encrypt | decrypt | sign | verify | digest | generateKey | deriveKey | deriveBits | importKey | exportKey | wrapKey | unwrapKey | 
 | :--: | :--: | :--: | :--: | :--: | :--: | :--: | :--: | :--: | :--: | :--: | :--: | :--: | 
+| [ECDSA](#ecdsa) |||:white_check_mark:|:white_check_mark:||:white_check_mark:|||:white_check_mark:|:white_check_mark:|||
 | [HMAC](#hmac) |||:white_check_mark:|:white_check_mark:||:white_check_mark:|||:white_check_mark:|:white_check_mark:|||
 | [RSA-OAEP](#rsa-oaep) |:white_check_mark:|:white_check_mark:||||:white_check_mark:|||:white_check_mark:|:white_check_mark:|||
 | [SHA](#sha) |||||:white_check_mark:||||||||
@@ -39,6 +46,52 @@ This library is still in active development and all algorithms are not yet suppo
 
 ## Algorithms
 
+### ECDSA
+
+The **ECDSA** algorithm is the implementation of operations described in [§23](https://www.w3.org/TR/WebCryptoAPI/#ecdsa) of the W3C specification.
+
+```go
+package main
+
+import (
+	"github.com/armortal/webcrypto-go"
+	"github.com/armortal/webcrypto-go/algorithms/ecdsa"
+)
+
+func main() {
+	// generate a new ECDSA key
+	key, err := webcrypto.Subtle().GenerateKey(
+		&ecdsa.Algorithm{
+			NamedCurve: "P-256",
+		}, true, webcrypto.Sign, webcrypto.Verify)
+	if err != nil {
+		panic(err)
+	}
+
+	ckp := key.(webcrypto.CryptoKeyPair)
+
+	// sign some data with the private key
+	sig, err := webcrypto.Subtle().Sign(&ecdsa.Algorithm{
+		Hash: "SHA-256",
+	}, ckp.PrivateKey(), []byte("test"))
+	if err != nil {
+		panic(err)
+	}
+
+	// verify the signature with the public key
+	ok, err := webcrypto.Subtle().Verify(&ecdsa.Algorithm{
+		Hash: "SHA-256",
+	}, ckp.PublicKey(), sig, []byte("test"))
+	if err != nil {
+		panic(err)
+	}
+
+	if !ok {
+		// didn't verify - do something
+	}
+}
+```
+
 ### HMAC
 
 The **HMAC** algorithm is the implementation of operations described in [§29](https://www.w3.org/TR/WebCryptoAPI/#hmac) of the W3C specification.
@@ -54,6 +107,12 @@ import (
 func main() {
 	// Generate a new key. A *hmac.CryptoKey is returned which implements webcrypto.CryptoKey
 	key, err := webcrypto.Subtle().GenerateKey(
+		&Algorithm{
+			Name: "ECDSA",
+			Params: ecdsa.KeyGenParams{
+
+			}
+		}
 		&hmac.Algorithm{
 			KeyGenParams: &hmac.KeyGenParams{
 				Hash: "SHA-256",

algorithm.go

@@ -14,6 +14,8 @@
 
 package webcrypto
 
+import "fmt"
+
 var algorithms = map[string]func() SubtleCrypto{}
 
 // Algorithm implements the Algorithm dictionary type as specified at
@@ -33,6 +35,10 @@ type KeyAlgorithm interface {
 // RegisterAlgorithm will register SubtleCrypto implementations referenced by the algorithm
 // name provided. When fn gets called, it should return a NEW instance of the implementation.
 func RegisterAlgorithm(name string, fn func() SubtleCrypto) {
+	_, ok := algorithms[name]
+	if ok {
+		panic(fmt.Sprintf("%s algorithm already registered", name))
+	}
 	algorithms[name] = fn
 }