Initial QSfera import

Server/vendor/github.com/lestrrat-go/dsig/README.md

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+# github.com/lestrrat-go/dsig [![CI](https://github.com/lestrrat-go/dsig/actions/workflows/ci.yml/badge.svg)](https://github.com/lestrrat-go/dsig/actions/workflows/ci.yml) [![Go Reference](https://pkg.go.dev/badge/github.com/lestrrat-go/dsig.svg)](https://pkg.go.dev/github.com/lestrrat-go/dsig) [![codecov.io](https://codecov.io/github/lestrrat-go/dsig/coverage.svg?branch=v1)](https://codecov.io/github/lestrrat-go/dsig?branch=v1)
+
+Go module providing low-level digital signature operations.
+
+While there are many standards for generating and verifying digital signatures, the core operations are virtually the same. This module implements the core functionality of digital signature generation / verifications in a framework agnostic way.
+
+# Features
+
+* RSA signatures (PKCS1v15 and PSS)
+* ECDSA signatures (P-256, P-384, P-521)
+* EdDSA signatures (Ed25519, Ed448)
+* HMAC signatures (SHA-256, SHA-384, SHA-512)
+* Support for crypto.Signer interface
+* Allows for dynamic additions of algorithms in limited cases.
+
+# SYNOPSIS
+
+<!-- INCLUDE(examples/dsig_readme_example_test.go) -->
+```go
+package examples_test
+
+import (
+  "crypto/ecdsa"
+  "crypto/ed25519"
+  "crypto/elliptic"
+  "crypto/rand"
+  "crypto/rsa"
+  "fmt"
+
+  "github.com/lestrrat-go/dsig"
+)
+
+func Example() {
+  payload := []byte("hello world")
+
+  // RSA signing and verification
+  {
+    privKey, err := rsa.GenerateKey(rand.Reader, 2048)
+    if err != nil {
+      fmt.Printf("failed to generate RSA key: %s\n", err)
+      return
+    }
+
+    // Sign with RSA-PSS SHA256
+    signature, err := dsig.Sign(privKey, dsig.RSAPSSWithSHA256, payload, nil)
+    if err != nil {
+      fmt.Printf("failed to sign with RSA: %s\n", err)
+      return
+    }
+
+    // Verify with RSA-PSS SHA256
+    err = dsig.Verify(&privKey.PublicKey, dsig.RSAPSSWithSHA256, payload, signature)
+    if err != nil {
+      fmt.Printf("failed to verify RSA signature: %s\n", err)
+      return
+    }
+  }
+
+  // ECDSA signing and verification
+  {
+    privKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+    if err != nil {
+      fmt.Printf("failed to generate ECDSA key: %s\n", err)
+      return
+    }
+
+    // Sign with ECDSA P-256 SHA256
+    signature, err := dsig.Sign(privKey, dsig.ECDSAWithP256AndSHA256, payload, nil)
+    if err != nil {
+      fmt.Printf("failed to sign with ECDSA: %s\n", err)
+      return
+    }
+
+    // Verify with ECDSA P-256 SHA256
+    err = dsig.Verify(&privKey.PublicKey, dsig.ECDSAWithP256AndSHA256, payload, signature)
+    if err != nil {
+      fmt.Printf("failed to verify ECDSA signature: %s\n", err)
+      return
+    }
+  }
+
+  // EdDSA signing and verification
+  {
+    pubKey, privKey, err := ed25519.GenerateKey(rand.Reader)
+    if err != nil {
+      fmt.Printf("failed to generate Ed25519 key: %s\n", err)
+      return
+    }
+
+    // Sign with EdDSA
+    signature, err := dsig.Sign(privKey, dsig.EdDSA, payload, nil)
+    if err != nil {
+      fmt.Printf("failed to sign with EdDSA: %s\n", err)
+      return
+    }
+
+    // Verify with EdDSA
+    err = dsig.Verify(pubKey, dsig.EdDSA, payload, signature)
+    if err != nil {
+      fmt.Printf("failed to verify EdDSA signature: %s\n", err)
+      return
+    }
+  }
+
+  // HMAC signing and verification
+  {
+    key := []byte("secret-key")
+
+    // Sign with HMAC SHA256
+    signature, err := dsig.Sign(key, dsig.HMACWithSHA256, payload, nil)
+    if err != nil {
+      fmt.Printf("failed to sign with HMAC: %s\n", err)
+      return
+    }
+
+    // Verify with HMAC SHA256
+    err = dsig.Verify(key, dsig.HMACWithSHA256, payload, signature)
+    if err != nil {
+      fmt.Printf("failed to verify HMAC signature: %s\n", err)
+      return
+    }
+  }
+  // OUTPUT:
+}
+```
+source: [examples/dsig_readme_example_test.go](https://github.com/lestrrat-go/dsig/blob/v1/examples/dsig_readme_example_test.go)
+<!-- END INCLUDE -->
+
+# Supported Algorithms
+
+| Constant | Algorithm | Key Type |
+|----------|-----------|----------|
+| `HMACWithSHA256` | HMAC using SHA-256 | []byte |
+| `HMACWithSHA384` | HMAC using SHA-384 | []byte |
+| `HMACWithSHA512` | HMAC using SHA-512 | []byte |
+| `RSAPKCS1v15WithSHA256` | RSA PKCS#1 v1.5 using SHA-256 | *rsa.PrivateKey / *rsa.PublicKey |
+| `RSAPKCS1v15WithSHA384` | RSA PKCS#1 v1.5 using SHA-384 | *rsa.PrivateKey / *rsa.PublicKey |
+| `RSAPKCS1v15WithSHA512` | RSA PKCS#1 v1.5 using SHA-512 | *rsa.PrivateKey / *rsa.PublicKey |
+| `RSAPSSWithSHA256` | RSA PSS using SHA-256 | *rsa.PrivateKey / *rsa.PublicKey |
+| `RSAPSSWithSHA384` | RSA PSS using SHA-384 | *rsa.PrivateKey / *rsa.PublicKey |
+| `RSAPSSWithSHA512` | RSA PSS using SHA-512 | *rsa.PrivateKey / *rsa.PublicKey |
+| `ECDSAWithP256AndSHA256` | ECDSA using P-256 and SHA-256 | *ecdsa.PrivateKey / *ecdsa.PublicKey |
+| `ECDSAWithP384AndSHA384` | ECDSA using P-384 and SHA-384 | *ecdsa.PrivateKey / *ecdsa.PublicKey |
+| `ECDSAWithP521AndSHA512` | ECDSA using P-521 and SHA-512 | *ecdsa.PrivateKey / *ecdsa.PublicKey |
+| `EdDSA` | EdDSA using Ed25519 or Ed448 | ed25519.PrivateKey / ed25519.PublicKey |
+
+# Description
+
+This library provides low-level digital signature operations. It does minimal parameter validation for performance, uses strongly typed APIs, and has minimal dependencies.
+
+# Contributions
+
+## Issues
+
+For bug reports and feature requests, please include failing tests when possible.
+
+## Pull Requests
+
+Please include tests that exercise your changes.
+
+# Related Libraries
+
+* [github.com/lestrrat-go/jwx](https://github.com/lestrrat-go/jwx) - JOSE (JWA/JWE/JWK/JWS/JWT) implementation