diff --git a/crypto/sharedkey/blake2s_test.go b/crypto/sharedkey/blake2s_test.go
new file mode 100644
index 0000000..f6cc546
--- /dev/null
+++ b/crypto/sharedkey/blake2s_test.go
@@ -0,0 +1,45 @@
+package sharedkey
+
+import (
+	"github.com/stretchr/testify/assert"
+	"math/rand"
+	"mpbl3p/shared"
+	"testing"
+)
+
+func TestBlake2s_GenerateVerify(t *testing.T) {
+	t.Run("GeneratedVerifies", func(t *testing.T) {
+		// ASSIGN
+		key := make([]byte, 16)
+		rand.Read(key)
+		buf := make([]byte, 500)
+		rand.Read(buf)
+
+		// ACT
+		b := Blake2s{key}
+		code := b.Generate(buf)
+
+		// ASSERT
+		err := b.Verify(buf, code)
+		assert.Nil(t, err)
+	})
+
+	t.Run("FlippedBitFailsVerify", func(t *testing.T) {
+		// ASSIGN
+		key := make([]byte, 16)
+		rand.Read(key)
+		buf := make([]byte, 500)
+		rand.Read(buf)
+
+		// ACT
+		b := Blake2s{key}
+		code := b.Generate(buf)
+
+		offset := rand.Intn(len(buf) * 8)
+		buf[offset/8] ^= 1 << (offset % 8)
+
+		// ASSERT
+		err := b.Verify(buf, code)
+		assert.Equal(t, shared.ErrBadChecksum, err)
+	})
+}