Migrate existing code

Author: pmuens

cmd/cli/main.go

@@ -0,0 +1,8 @@
+package main
+
+import "fmt"
+
+
+func main() {
+	fmt.Printf("Hello %s\n", "World")
+}

pkg/hash/errors.go

@@ -0,0 +1,6 @@
+package hash
+
+import "fmt"
+
+// ErrSampleNonce is returned if the random nonce can't be sampled.
+var ErrSampleNonce = fmt.Errorf("unable to sample random nonce")

pkg/hash/hash.go

@@ -0,0 +1,60 @@
+package hash
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"io"
+)
+
+// Commitment is an instance of a commitment.
+type Commitment struct {
+	hash  [32]byte
+	nonce [32]byte
+}
+
+// NewCommitment creates a new instance of a commitment.
+func NewCommitment(hash [32]byte, nonce [32]byte) *Commitment {
+	return &Commitment{
+		hash:  hash,
+		nonce: nonce,
+	}
+}
+
+// Commit creates a commitment that commits to arbitrary data.
+// Returns an error if the nonce generation fails.
+func Commit(data ...[]byte) (*Commitment, error) {
+	var nonce [32]byte
+	_, err := io.ReadFull(rand.Reader, nonce[:])
+	if err != nil {
+		return nil, ErrSampleNonce
+	}
+
+	hash := generateCommitment(nonce, data...)
+
+	pair := NewCommitment(hash, nonce)
+
+	return pair, nil
+}
+
+// Verify verifies the correctness of a commitment to data.
+func Verify(pair *Commitment, data ...[]byte) bool {
+	hash := generateCommitment(pair.nonce, data...)
+
+	return hash == pair.hash
+}
+
+// generateCommitment creates the commitment by hashing the data and nonce
+// using SHA-256.
+func generateCommitment(nonce [32]byte, data ...[]byte) [32]byte {
+	var bz []byte
+
+	// Data.
+	for _, d := range data {
+		bz = append(bz, d...)
+	}
+
+	// Nonce.
+	bz = append(bz, nonce[:]...)
+
+	return sha256.Sum256(bz)
+}

pkg/hash/hash_test.go

@@ -0,0 +1,67 @@
+package hash_test
+
+import (
+	"testing"
+
+	"github.com/primefactor-io/commitment/pkg/hash"
+)
+
+func TestCommitVerify(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Commit / Verify - Valid (single-data)", func(t *testing.T) {
+		t.Parallel()
+
+		data := []byte("Hello World")
+
+		comm, _ := hash.Commit(data)
+		isValid := hash.Verify(comm, data)
+
+		if isValid != true {
+			t.Error("Commitment verification failed")
+		}
+	})
+
+	t.Run("Commit / Verify - Valid (multi-data)", func(t *testing.T) {
+		t.Parallel()
+
+		data1 := []byte("Hello")
+		data2 := []byte("World")
+
+		comm, _ := hash.Commit(data1, data2)
+		isValid := hash.Verify(comm, data1, data2)
+
+		if isValid != true {
+			t.Error("Commitment verification failed")
+		}
+	})
+
+	t.Run("Commit / Verify - Invalid (single-data)", func(t *testing.T) {
+		t.Parallel()
+
+		data1 := []byte("Hello World")
+		data2 := []byte("Hello, World")
+
+		comm, _ := hash.Commit(data1)
+		isValid := hash.Verify(comm, data2)
+
+		if isValid != false {
+			t.Error("Commitment verification failed")
+		}
+	})
+
+	t.Run("Commit / Verify - Invalid (multi-data)", func(t *testing.T) {
+		t.Parallel()
+
+		data1 := []byte("Hello")
+		data2 := []byte("World")
+		data3 := []byte(", World")
+
+		comm, _ := hash.Commit(data1, data2)
+		isValid := hash.Verify(comm, data1, data3)
+
+		if isValid != false {
+			t.Error("Commitment verification failed")
+		}
+	})
+}