---
title: Use a randomly-generated IV
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Datadog Security > Code Security > Static Code Analysis (SAST) > SAST
  Rules > Use a randomly-generated IV
---

# Use a randomly-generated IV

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# Important note for users on the following Datadog sites: app.ddog-gov.com

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This product is not supported for your selected [Datadog site](https://docs.datadoghq.com/getting_started/site). ().
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## Metadata{% #metadata %}

**ID:** `java-security/random-iv`

**Language:** Java

**Severity:** Warning

**Category:** Security

**CWE**: [1204](https://cwe.mitre.org/data/definitions/1204.html)

## Description{% #description %}

The initialization vector (IV) for a cryptographic operation must be random and not statically declared. Instead of using a static initialization vector, use the `SecureRandom` class that will initialize your vector with real random values.

#### Learn More{% #learn-more %}

- [`SecureRandom` documentation](https://docs.oracle.com/javase/8/docs/api/java/security/SecureRandom.html)
- [CWE-1204: Generation of Weak Initialization Vector (IV)](https://cwe.mitre.org/data/definitions/1204.html)

## Non-Compliant Code Examples{% #non-compliant-code-examples %}

```java
public class Foo {
    void bad() {
        byte[] iv = new byte[] { 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, };
    }

    void alsoBad() {
        byte[] iv = "secret iv in here".getBytes();
    }
}
```

## Compliant Code Examples{% #compliant-code-examples %}

```java
public class Foo {
    void good() {
        SecureRandom random = new SecureRandom();
        byte iv[] = new byte[16];
        random.nextBytes(bytes);
    }
}
```
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