此问题可能是由于私钥密码不匹配而导致的。可以使用以下代码示例来解决问题：

try {
    KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");
    keyStore.load(null);

    String alias = "my_key";
    KeyStore.Entry entry = keyStore.getEntry(alias, null);

    if (entry == null) {
        Log.e("TAG", "No key found under alias: " + alias);
        return;
    }

    if (!(entry instanceof KeyStore.PrivateKeyEntry)) {
        Log.e("TAG", "Not an instance of a PrivateKeyEntry");
        return;
    }

    PrivateKey privateKey = ((KeyStore.PrivateKeyEntry)entry).getPrivateKey();

    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
    cipher.init(Cipher.DECRYPT_MODE, privateKey);

    byte[] encryptedData = ... // encrypted data
    byte[] decryptedData = cipher.doFinal(encryptedData);
    
    String decryptedString = new String(decryptedData, StandardCharsets.UTF_8);
    Log.i("TAG", "Decrypted string: " + decryptedString);
} catch (Exception e) {
    Log.e("TAG", "Exception while decrypting: " + e.getMessage());
}

此代码示例从 Android 密钥库中获取了一个私钥，并使用 RSA 算法和 PKCS#1 填充模式对加密数据进行解密。如果私钥密码不匹配，则会抛出异常。