Updated on 2026-08-14

app/src/main/java/com/tangem/domain/cardReader/PBKDF2.java

@@ -0,0 +1,103 @@
+
+package com.tangem.domain.cardReader;
+
+import org.spongycastle.crypto.CipherParameters;
+import org.spongycastle.crypto.digests.SHA256Digest;
+import org.spongycastle.crypto.macs.HMac;
+import org.spongycastle.crypto.params.KeyParameter;
+
+import java.security.InvalidKeyException;
+import java.util.Arrays;
+
+public final class PBKDF2 {
+    private static final HMac F =new HMac(new SHA256Digest());
+
+    /**
+     * Derive a key.
+     *
+     * @param password   The password to derive the key from.
+     * @param iterations The iteration count.
+     * @return Returns a key derived with the specified parameters.
+     * @throws InvalidKeyException If the specified length for the derived key
+     *                             is to long.
+     */
+    public static byte[] deriveKey(final byte[] password, final byte[] salt, final int iterations) throws InvalidKeyException {
+        return deriveKey(password, salt, iterations, F.getMacSize());
+    }
+
+    /**
+     * Derive a key with a specified length.
+     *
+     * @param password   The password to derive the key from.
+     * @param iterations The iteration count.
+     * @param len      The length of the derived key.
+     * @return Returns a key derived with the specified parameters.
+     * @throws InvalidKeyException If the specified length for the derived key
+     *                             is to long.
+     */
+    public static byte[] deriveKey(final byte[] password, final byte[] salt, final int iterations, final int len) throws InvalidKeyException {
+        // Check key length
+        if (len > ((Math.pow(2, 32) - 1) * F.getMacSize()))
+            throw new InvalidKeyException("Derived key to long");
+
+        byte[] derivedKey = new byte[len];
+
+        final int J = 0;
+        final int K = F.getMacSize();
+        final int U = F.getMacSize() << 1;
+        final int B = K + U;
+        final byte[] workingArray = new byte[K + U + 4];
+
+        // Initialize F
+        CipherParameters macParams = new KeyParameter(password);
+        F.init(macParams);
+
+        // Perform iterations
+        for (int kpos = 0, blk = 1; kpos < len; kpos += K, blk++) {
+            storeInt32BE(blk, workingArray, B);
+
+            F.update(salt, 0, salt.length);
+
+            F.reset();
+            F.update(salt, 0, salt.length);
+            F.update(workingArray, B, 4);
+            F.doFinal(workingArray, U);
+            System.arraycopy(workingArray, U, workingArray, J, K);
+
+            for (int i = 1, j = J, k = K; i < iterations; i++) {
+                F.init(macParams);
+                F.update(workingArray, j, K);
+                F.doFinal(workingArray, k);
+
+                for (int u = U, v = k; u < B; u++, v++)
+                    workingArray[u] ^= workingArray[v];
+
+                int swp = k;
+                k = j;
+                j = swp;
+            }
+
+            int tocpy = Math.min(len - kpos, K);
+            System.arraycopy(workingArray, U, derivedKey, kpos, tocpy);
+        }
+
+        Arrays.fill(workingArray, (byte) 0);
+
+        return derivedKey;
+    }
+
+    /**
+     * Convert a 32-bit integer value into a big-endian byte array
+     *
+     * @param value  The integer value to convert
+     * @param bytes  The byte array to store the converted value
+     * @param offSet The offset in the output byte array
+     */
+    public static void storeInt32BE(int value, byte[] bytes, int offSet) {
+        bytes[offSet + 3] = (byte) (value);
+        bytes[offSet + 2] = (byte) (value >>> 8);
+        bytes[offSet + 1] = (byte) (value >>> 16);
+        bytes[offSet] = (byte) (value >>> 24);
+    }
+
+}