Add SHA256 computation and verification functionality

- Implemented computeSHA256 function to generate hex-encoded SHA256 hashes.
- Added verifySHA256 function to validate input data against expected hash in a WebAssembly context.
- Created main_test.go to include unit tests for computeSHA256 with various input cases.

software-verifier/main.go

@@ -0,0 +1,36 @@
+//go:build js && wasm
+// +build js,wasm
+
+package main
+
+import (
+	"fmt"
+	"syscall/js"
+)
+
+// verifySHA256 verifies that the SHA256 hash of the input data matches the provided expected hash.
+func verifySHA256(this js.Value, args []js.Value) any {
+	if len(args) < 2 {
+		return js.ValueOf("invalid arguments: expected (data []uint8, expectedHash string)")
+	}
+
+	dataLen := args[0].Get("length").Int()
+	data := make([]byte, dataLen)
+	js.CopyBytesToGo(data, args[0])
+
+	expectedHash := args[1].String()
+	actualHash := computeSHA256(data)
+
+	if actualHash == expectedHash {
+		return js.ValueOf(true)
+	}
+	return js.ValueOf(fmt.Sprintf("hash mismatch: got %s, expected %s", actualHash, expectedHash))
+}
+
+// main initializes the WebAssembly module and exposes verifySHA256 to the JavaScript global scope.
+func main() {
+	c := make(chan struct{})
+	fmt.Println("Software Verifier WASM Initialized")
+	js.Global().Set("verifySHA256", js.FuncOf(verifySHA256))
+	<-c
+}

software-verifier/main_test.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"testing"
+)
+
+func TestComputeSHA256(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "Empty string",
+			input:    "",
+			expected: "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+		},
+		{
+			name:     "Hello world",
+			input:    "hello world",
+			expected: "b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9",
+		},
+		{
+			name:     "Software Station",
+			input:    "Software Station",
+			expected: "2f94338443740cd0ca2afbd1c177f8a624a521d1668d9eaf4e2439ae06e32b11",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			actual := computeSHA256([]byte(tt.input))
+			if actual != tt.expected {
+				t.Errorf("computeSHA256() = %v, want %v", actual, tt.expected)
+			}
+		})
+	}
+}
+

software-verifier/verifier.go

@@ -0,0 +1,13 @@
+package main
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+)
+
+// computeSHA256 returns the hex-encoded SHA256 hash of the input data.
+func computeSHA256(data []byte) string {
+	hash := sha256.Sum256(data)
+	return hex.EncodeToString(hash[:])
+}
+