working mib login and list accounts

2026-05-12 04:19:52 +05:00
parent 31c8a5500d
commit 076a58359a
73 changed files with 3076 additions and 550 deletions
@@ -0,0 +1,56 @@
+package sh.sar.basedbank.util
+
+import javax.crypto.Mac
+import javax.crypto.spec.SecretKeySpec
+import kotlin.experimental.and
+
+object Totp {
+
+    /**
+     * Generate a 6-digit TOTP code from a Base32-encoded secret (RFC 6238 / RFC 4226).
+     * Uses HmacSHA1, 30-second window, 6 digits — matching standard authenticator apps.
+     */
+    fun generate(base32Secret: String, digits: Int = 6, periodSeconds: Long = 30): String {
+        val key = base32Decode(base32Secret.uppercase().replace(" ", "").replace("-", ""))
+        val counter = System.currentTimeMillis() / 1000L / periodSeconds
+        val otp = hotp(key, counter, digits)
+        return otp.toString().padStart(digits, '0')
+    }
+
+    private fun hotp(key: ByteArray, counter: Long, digits: Int): Int {
+        val msg = ByteArray(8) { i -> ((counter shr ((7 - i) * 8)) and 0xFF).toByte() }
+        val mac = Mac.getInstance("HmacSHA1")
+        mac.init(SecretKeySpec(key, "HmacSHA1"))
+        val hash = mac.doFinal(msg)
+
+        val offset = (hash[hash.size - 1] and 0x0F).toInt()
+        val code = ((hash[offset].toInt() and 0x7F) shl 24) or
+                   ((hash[offset + 1].toInt() and 0xFF) shl 16) or
+                   ((hash[offset + 2].toInt() and 0xFF) shl 8) or
+                   (hash[offset + 3].toInt() and 0xFF)
+
+        val modulus = Math.pow(10.0, digits.toDouble()).toInt()
+        return code % modulus
+    }
+
+    private val BASE32_CHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"
+
+    private fun base32Decode(input: String): ByteArray {
+        val clean = input.trimEnd('=')
+        val output = ByteArray(clean.length * 5 / 8)
+        var buffer = 0
+        var bitsLeft = 0
+        var outIndex = 0
+        for (c in clean) {
+            val v = BASE32_CHARS.indexOf(c)
+            require(v >= 0) { "Invalid Base32 character: $c" }
+            buffer = (buffer shl 5) or v
+            bitsLeft += 5
+            if (bitsLeft >= 8) {
+                bitsLeft -= 8
+                output[outIndex++] = ((buffer shr bitsLeft) and 0xFF).toByte()
+            }
+        }
+        return output
+    }
+}