HPolyC example.

vfs/adiantum/example_test.go

@@ -0,0 +1,52 @@
+//go:build (linux || darwin || windows || freebsd || illumos) && !sqlite3_nosys
+
+package adiantum_test
+
+import (
+	"crypto/rand"
+	"log"
+	"os"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/vfs"
+	"github.com/ncruces/go-sqlite3/vfs/adiantum"
+	"golang.org/x/crypto/argon2"
+	"lukechampine.com/adiantum/hbsh"
+	"lukechampine.com/adiantum/hpolyc"
+)
+
+func ExampleRegister_hpolyc() {
+	adiantum.Register("hpolyc", vfs.Find(""), hpolycCreator{})
+
+	db, err := sqlite3.Open("file:demo.db?vfs=hpolyc" +
+		"&textkey=correct+horse+battery+staple")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.Remove("./demo.db")
+	defer db.Close()
+	// Output:
+}
+
+type hpolycCreator struct{}
+
+// HBSH creates an HBSH cipher given a key.
+func (hpolycCreator) HBSH(key []byte) *hbsh.HBSH {
+	if len(key) != 32 {
+		// Key is not appropriate, return nil.
+		return nil
+	}
+	return hpolyc.New(key)
+}
+
+// KDF gets a key from a secret.
+func (hpolycCreator) KDF(secret string) []byte {
+	if secret == "" {
+		// No secret is given, generate a random key.
+		key := make([]byte, 32)
+		n, _ := rand.Read(key)
+		return key[:n]
+	}
+	// Hash the secret with a KDF.
+	return argon2.IDKey([]byte(secret), []byte("hpolyc"), 3, 64*1024, 4, 32)
+}