---
title: "Calculate Cryptographic Operation Latency SLIs"
slug: "calculate-cryptographic-operation-latency-slis"
updated: 2026-07-29T05:33:33Z
published: 2026-07-29T05:33:33Z
canonical: "support.fortanix.com/calculate-cryptographic-operation-latency-slis"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://support.fortanix.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Calculate Cryptographic Operation Latency SLIs

## 1.0 Introduction

This article describes how to use the **Fortanix-Data-Security-Manager (DSM)** Audit Logs API `(/sys/v1/logs)` and Get Key API `(/crypto/v1/keys/{key_id})` to retrieve the information required to calculate Service Level Indicators (SLIs) for cryptographic operation latency. It explains how to obtain audit log information and key metadata to calculate latency statistics for cryptographic operations grouped by operation type, key type, and key size.

## 2.0 Retrieve Audit Logs

The Audit Logs API `(/sys/v1/logs)` retrieves audit log entries for cryptographic operations. The endpoint is paginated and returns up to 1000 log entries per request. Use the query parameters to define the time range and retrieve additional pages of results.

> [!NOTE]
> NOTE
> 
> - Audit logs are returned in reverse chronological order.
> - The time range specified by `range_from` and` range_to` cannot exceed 30 days.
> - The maximum value for the `size` parameter is `1000`.

### 2.1 Query Parameters

| Parameter | Description |
| --- | --- |
| `range_from` | Unix timestamp that specifies the beginning of the time range. |
| `range_to` | Unix timestamp that specifies the end of the time range. |
| `size` | Maximum number of audit log entries to return. The value cannot exceed 1000. |
| `previous_id` | UUID of the last log returned by the previous request. Use this parameter to retrieve the next page of results. |

### 2.2 Example: Retrieve the First Page of Audit Logs

The following request retrieves up to 1000 audit logs between July 1 and July 31, 2026.

```bash
GET {dsm_url}/sys/v1/logs?range_from=1782889200&range_to=1785499200&size=1000
```

### 2.3 Example: Retrieve the Next Page

Use the `previous_id` parameter to retrieve the next page. The last log entry returned by the previous request has the ID `xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx`.

```bash
GET {dsm_url}/sys/v1/logs?range_from=1782889200&range_to=1785499200&size=1000&previous_id=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
```

### 2.4 Response Schema

The Audit Logs API returns a JSON document containing an array of audit log entries.

```json
{
  "hits": [
    {
      "_id": "Uuid",
      "_source": {
        "action_type": "string",
        "object_id": "Uuid",
        "message": "string", // For crypto operations, this has the form:
        // “App "{app_name}" used key "{key_name}" to perform "{crypto_operation}" operation”
        // {crypto_operation} can be Encryption, Decryption, Signing, Verification, etc.
        "response_time": {
          "secs": "int",
          "nanos": "int",
        }
      }
    },
  ]
}
```

The Log API response has the following fields:

| Field | Description |
| --- | --- |
| `_id` | Unique identifier for the audit log entry. Use this value with `previous_id` to retrieve the next page of results. |
| `action_type` | Type of audited action. Filter entries with the value `CRYPTOOPERATION `to calculate cryptographic operation latency. |
| `object_id` | Identifier of the key used for the cryptographic operation. Use this value to retrieve key metadata with the Keys API. |
| `message` | Describes the cryptographic operation, including the application name, key name, and operation type, such as encryption, decryption, signing, or verification. |
| `response_time.secs` | Whole seconds component of the operation latency. |
| `response_time.nanos` | Nanoseconds component of the operation latency. |

## 3.0 Retrieve Key Metadata

Use the Get Key API `(/crypto/v1/keys/{key_id})` to retrieve the key type and key size.

For audit log entries where `action_type` is `CRYPTOOPERATION`, the` object_id` field contains the ID of the key used to perform the operation.

Use the key ID from the audit log to retrieve the key metadata with the Get Key API.

```bash
GET /crypto/v1/keys/{key_id}
```

The response includes metadata for the specified key.

```json
{
  "kid": "Uuid",
  "key_size": "int",
  "obj_type": "string",
}
```

**Response fields**

| Field | Description |
| --- | --- |
| `kid` | Unique identifier of the key. |
| `key_size` | Size of the key, in bits. |
| `obj_type` | Cryptographic key type such as AES or RSA |

Combine the following information to calculate latency SLIs for cryptographic operations:

- Operation type (from the `message` field)
- Operation latency (from `response_time`)
- Key type (`obj_type`)
- Key size (`key_size`)

Group the resulting latency statistics by operation type, key type, and key size to analyse the performance of different cryptographic operations.

Fortanix Data Security Manager (DSM) is the world’s first cloud service secured with Intel® SGX. With Fortanix DSM, you can securely generate, store, and use cryptographic keys and certificates, as well as other secrets such as passwords, API keys, tokens, or any blob of data. Your business-critical applications and containers can integrate with Fortanix DSM using legacy cryptographic interfaces (PKCS#11, CNG, and JCE) or using the native Fortanix DSM RESTful interface.