diff --git a/crypto/bls/go.mod b/crypto/bls/go.mod
new file mode 100644
index 000000000..45667a011
--- /dev/null
+++ b/crypto/bls/go.mod
@@ -0,0 +1,12 @@
+module github.com/tendermint/tendermint/crypto/bls
+
+go 1.17
+
+require github.com/tendermint/tendermint v0.35.4
+
+require (
+	github.com/oasisprotocol/curve25519-voi v0.0.0-20210609091139-0a56a4bca00b // indirect
+	github.com/petermattis/goid v0.0.0-20180202154549-b0b1615b78e5 // indirect
+	github.com/sasha-s/go-deadlock v0.2.1-0.20190427202633-1595213edefa // indirect
+	golang.org/x/sys v0.0.0-20220412211240-33da011f77ad // indirect
+)
diff --git a/crypto/bls/simple_sign_test.go b/crypto/bls/simple_sign_test.go
new file mode 100644
index 000000000..11c026579
--- /dev/null
+++ b/crypto/bls/simple_sign_test.go
@@ -0,0 +1,37 @@
+package bls
+
+import (
+	"testing"
+
+	"github.com/tendermint/tendermint/crypto/ed25519"
+)
+
+func TestEd25519SignVerify(t *testing.T) {
+	m := []byte("a test message to be signed")
+	privKey := ed25519.GenPrivKey()
+	pubKey := privKey.PubKey()
+
+	sig, err := privKey.Sign(m)
+	if err != nil {
+		t.Error("Unexpected nil signature or error", m, sig, err)
+	}
+	if !pubKey.VerifySignature(m, sig) {
+		t.Error("Failed to verify signature produced by the key", m, sig)
+	}
+	if pubKey.VerifySignature(scrambleBytes(m), sig) {
+		t.Error("Unexpected to verify scrambled message", scrambleBytes(m), sig)
+	}
+	if pubKey.VerifySignature(m, scrambleBytes(sig)) {
+		t.Error("Unexpected to verify scrambled signature", m, scrambleBytes(sig))
+	}
+}
+
+// Scrambles a byte array, currently just flipping a bit.
+// TODO: implement a more complex scrambling method.
+func scrambleBytes(b []byte) []byte {
+	bb := make([]byte, len(b))
+	copy(bb, b)
+	index := len(b) / 2
+	bb[index] ^= 1
+	return bb
+}