272 lines
7.2 KiB
Markdown
272 lines
7.2 KiB
Markdown
# JWK [](https://pkg.go.dev/github.com/lestrrat-go/jwx/jwk)
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Package jwk implements JWK as described in [RFC7517](https://tools.ietf.org/html/rfc7517)
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* Parse and work with RSA/EC/Symmetric/OKP JWK types
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* Convert to and from JSON
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* Convert to and from raw key types (e.g. *rsa.PrivateKey)
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* Ability to keep a JWKS fresh.
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Examples are located in the examples directory ([jwk_example_test.go](../examples/jwk_example_test.go))
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Supported key types:
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| kty | Curve | Go Key Type |
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|:----|:------------------------|:----------------------------------------------|
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| RSA | N/A | rsa.PrivateKey / rsa.PublicKey (2) |
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| EC | P-256<br>P-384<br>P-521<br>secp256k1 (1) | ecdsa.PrivateKey / ecdsa.PublicKey (2) |
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| oct | N/A | []byte |
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| OKP | Ed25519 (1) | ed25519.PrivateKey / ed25519.PublicKey (2) |
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| | X25519 (1) | (jwx/)x25519.PrivateKey / x25519.PublicKey (2)|
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* Note 1: Experimental
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* Note 2: Either value or pointers accepted (e.g. rsa.PrivateKey or *rsa.PrivateKey)
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# SYNOPSIS
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## Parse a JWK or a JWK set
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```go
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// Parse a single JWK key.
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key, err := jwk.ParseKey(...)
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// Parse a JWK set (or a single JWK key)
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set, err := jwk.Parse(...)
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```
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## Create JWK keys from raw keys
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```go
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func ExampleNew() {
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// New returns different underlying types of jwk.Key objects
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// depending on the input value.
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// []byte -> jwk.SymmetricKey
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{
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raw := []byte("Lorem Ipsum")
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key, err := jwk.New(raw)
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if err != nil {
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fmt.Printf("failed to create symmetric key: %s\n", err)
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return
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}
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if _, ok := key.(jwk.SymmetricKey); !ok {
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fmt.Printf("expected jwk.SymmetricKey, got %T\n", key)
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return
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}
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}
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// *rsa.PrivateKey -> jwk.RSAPrivateKey
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// *rsa.PublicKey -> jwk.RSAPublicKey
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{
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raw, err := rsa.GenerateKey(rand.Reader, 2048)
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if err != nil {
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fmt.Printf("failed to generate new RSA privatre key: %s\n", err)
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return
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}
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key, err := jwk.New(raw)
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if err != nil {
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fmt.Printf("failed to create symmetric key: %s\n", err)
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return
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}
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if _, ok := key.(jwk.RSAPrivateKey); !ok {
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fmt.Printf("expected jwk.SymmetricKey, got %T\n", key)
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return
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}
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// PublicKey is omitted for brevity
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}
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// *ecdsa.PrivateKey -> jwk.ECDSAPrivateKey
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// *ecdsa.PublicKey -> jwk.ECDSAPublicKey
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{
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raw, err := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
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if err != nil {
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fmt.Printf("failed to generate new ECDSA privatre key: %s\n", err)
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return
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}
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key, err := jwk.New(raw)
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if err != nil {
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fmt.Printf("failed to create symmetric key: %s\n", err)
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return
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}
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if _, ok := key.(jwk.ECDSAPrivateKey); !ok {
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fmt.Printf("expected jwk.SymmetricKey, got %T\n", key)
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return
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}
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// PublicKey is omitted for brevity
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}
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// OUTPUT:
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}
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```
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# Get the JSON representation of a key
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```go
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func ExampleMarshalJSON() {
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// to get the same values every time, we need to create a static source
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// of "randomness"
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rdr := bytes.NewReader([]byte("01234567890123456789012345678901234567890123456789ABCDEF"))
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raw, err := ecdsa.GenerateKey(elliptic.P384(), rdr)
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if err != nil {
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fmt.Printf("failed to generate new ECDSA privatre key: %s\n", err)
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return
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}
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key, err := jwk.New(raw)
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if err != nil {
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fmt.Printf("failed to create symmetric key: %s\n", err)
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return
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}
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if _, ok := key.(jwk.ECDSAPrivateKey); !ok {
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fmt.Printf("expected jwk.SymmetricKey, got %T\n", key)
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return
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}
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key.Set(jwk.KeyIDKey, "mykey")
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buf, err := json.MarshalIndent(key, "", " ")
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if err != nil {
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fmt.Printf("failed to marshal key into JSON: %s\n", err)
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return
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}
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fmt.Printf("%s\n", buf)
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// OUTPUT:
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// {
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// "kty": "EC",
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// "crv": "P-384",
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// "d": "ODkwMTIzNDU2Nzg5MDEyMz7deMbyLt8g4cjcxozuIoygLLlAeoQ1AfM9TSvxkFHJ",
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// "kid": "mykey",
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// "x": "gvvRMqm1w5aHn7sVNA2QUJeOVcedUnmiug6VhU834gzS9k87crVwu9dz7uLOdoQl",
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// "y": "7fVF7b6J_6_g6Wu9RuJw8geWxEi5ja9Gp2TSdELm5u2E-M7IF-bsxqcdOj3n1n7N"
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// }
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}
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```
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# Auto-Refresh a key during a long running process
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```go
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func ExampleAutoRefresh() {
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ctx, cancel := context.WithCancel(context.Background())
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const googleCerts = `https://www.googleapis.com/oauth2/v3/certs`
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ar := jwk.NewAutoRefresh(ctx)
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// Tell *jwk.AutoRefresh that we only want to refresh this JWKS
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// when it needs to (based on Cache-Control or Expires header from
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// the HTTP response). If the calculated minimum refresh interval is less
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// than 15 minutes, don't go refreshing any earlier than 15 minutes.
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ar.Configure(googleCerts, jwk.WithMinRefreshInterval(15*time.Minute))
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// Refresh the JWKS once before getting into the main loop.
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// This allows you to check if the JWKS is available before we start
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// a long-running program
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_, err := ar.Refresh(ctx, googleCerts)
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if err != nil {
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fmt.Printf("failed to refresh google JWKS: %s\n", err)
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return
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}
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// Pretend that this is your program's main loop
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MAIN:
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for {
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select {
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case <-ctx.Done():
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break MAIN
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default:
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}
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keyset, err := ar.Fetch(ctx, googleCerts)
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if err != nil {
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fmt.Printf("failed to fetch google JWKS: %s\n", err)
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return
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}
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_ = keyset
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// Do interesting stuff with the keyset... but here, we just
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// sleep for a bit
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time.Sleep(time.Second)
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// Because we're a dummy program, we just cancel the loop now.
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// If this were a real program, you prosumably loop forever
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cancel()
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}
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// OUTPUT:
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}
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```
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Parse and use a JWK key:
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```go
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import (
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"encoding/json"
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"log"
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"github.com/lestrrat-go/jwx/jwk"
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)
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func main() {
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set, err := jwk.Fetch(context.Background(), "https://www.googleapis.com/oauth2/v3/certs")
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if err != nil {
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log.Printf("failed to parse JWK: %s", err)
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return
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}
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// Key sets can be serialized back to JSON
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{
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jsonbuf, err := json.Marshal(set)
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if err != nil {
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log.Printf("failed to marshal key set into JSON: %s", err)
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return
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}
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log.Printf("%s", jsonbuf)
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}
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for it := set.Iterate(context.Background()); it.Next(context.Background()); {
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pair := it.Pair()
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key := pair.Value.(jwk.Key)
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var rawkey interface{} // This is the raw key, like *rsa.PrivateKey or *ecdsa.PrivateKey
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if err := key.Raw(&rawkey); err != nil {
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log.Printf("failed to create public key: %s", err)
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return
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}
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// Use rawkey for jws.Verify() or whatever.
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_ = rawkey
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// You can create jwk.Key from a raw key, too
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fromRawKey, err := jwk.New(rawkey)
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// Keys can be serialized back to JSON
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jsonbuf, err := json.Marshal(key)
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if err != nil {
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log.Printf("failed to marshal key into JSON: %s", err)
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return
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}
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log.Printf("%s", jsonbuf)
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// If you know the underlying Key type (RSA, EC, Symmetric), you can
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// create an empy instance first
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// key := jwk.NewRSAPrivateKey()
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// ..and then use json.Unmarshal
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// json.Unmarshal(key, jsonbuf)
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//
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// but if you don't know the type first, you have an abstract type
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// jwk.Key, which can't be used as the first argument to json.Unmarshal
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//
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// In this case, use jwk.Parse()
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fromJsonKey, err := jwk.ParseBytes(jsonbuf)
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if err != nil {
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log.Printf("failed to parse json: %s", err)
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return
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}
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_ = fromJsonKey
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_ = fromRawKey
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}
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}
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```
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