Keyless Signature Infrastructure Provider (rsyslog-ksi-ls12) — rsyslog 8.37.0 documentation

# Keyless Signature Infrastructure Provider (rsyslog-ksi-ls12)

Module Name: | rsyslog-ksi-ls12
Author: | Guardtime & Adiscon
Available Since: | 8.27

## Purpose

The `rsyslog-ksi-ls12` module enables record level log signing with Guardtime KSI blockchain. KSI keyless signatures provide long-term log integrity and prove the time of log records cryptographically using independent verification.

Main features of the `rsyslog-ksi-ls12` module are:

- Automated online signing of file output log.
- Efficient block-based signing with record-level verification.
- Log records removal detection.

For best results use the `rsyslog-ksi-ls12` module together with Guardtime `logksi` tool, which will become handy in:

- Signing recovery.
- Extension of KSI signatures inside the log signature file.
- Verification of the log using log signatures.
- Extraction of record-level signatures.
- Integration of log signature files (necessary when signing in async mode).

## Getting Started

To get started with log signing:

- Sign up to the Guardtime tryout service to be able to connect to KSI blockchain: guardtime.com/technology/blockchain-developers
- Install the `libksi` library (v3.13 or later) from Guardtime repository either for RHEL/CentOS 6 http://download.guardtime.com/ksi/configuration/guardtime.el6.repo or RHEL/CentOS 7 http://download.guardtime.com/ksi/configuration/guardtime.el7.repo
- Install the `rsyslog-ksi-ls12` module (same version as rsyslog) from Adiscon repository.
- Install the accompanying `logksi` tool (v1.0 or later) from Guardtime repository either for RHEL/CentOS 6 http://download.guardtime.com/ksi/configuration/guardtime.el6.repo or RHEL/CentOS 7 http://download.guardtime.com/ksi/configuration/guardtime.el7.repo

## Configuration Parameters

Currently the log signing is only supported by the file output module, thus the action type must be `omfile`. To activate signing, add the following parameters to the action of interest in your rsyslog configuration file:

Note

Parameter names are case-insensitive.

### Action Parameters

#### sig.provider

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
word | none | no | none

Specifies the signature provider; in case of `rsyslog-ksi-ls12` package this is `"ksi_ls12"`.

#### sig.block.levelLimit

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
size | none | yes | none

Defines the maximum level of the root of the local aggregation tree per one block.

#### sig.aggregator.url

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
word | none | yes | none

Defines the endpoint of the KSI signing service in KSI Gateway. Supported URL schemes are:

> - http://
> - ksi+http://
> - ksi+tcp://

#### sig.aggregator.user

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
word | none | yes | none

Specifies the login name for the KSI signing service.

#### sig.aggregator.key

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
word | none | yes | none

Specifies the key for the login name.

#### sig.syncmode

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
string | sync | no | none

Defines the signing mode: `"sync"` or `"async"`.

#### sig.hashFunction

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
word | SH2-256 | no | none

Defines the hash function to be used for hashing. The following hash algorithms are currently supported:

> - SHA1
> - SHA2-256
> - RIPEMD-160
> - SHA2-224
> - SHA2-384
> - SHA2-512
> - RIPEMD-256
> - SHA3-244
> - SHA3-256
> - SHA3-384
> - SHA3-512
> - SM3

#### sig.block.timeLimit

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
int | 0 | no | none

Defines the maximum duration of one block in seconds. Default value indicates that no time limit is set.

#### sig.keepTreeHashes

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
binary | off | no | none

Turns on/off the storing of the hashes that were used as leaves for building the Merkle tree.

#### sig.keepRecordHashes

type | default | mandatory | `obsolete legacy` directive
--- | --- | --- | ---
binary | on | no | none

Turns on/off the storing of the hashes of the log records.

The log signature file, which stores the KSI signatures and information about the signed blocks, appears in the same directory as the log file itself; it is named `<logfile>.logsig`.

## See Also

To better understand the log signing mechanism and the module’s possibilities it is advised to consult with:

- KSI Rsyslog Integration User Guide
- KSI Developer Guide

Access for both of these documents requires Guardtime tryout service credentials, available from https://guardtime.com/technology/blockchain-developers

## Examples

### Signing logs with KSI

To sign the logs in `/var/log/secure` with KSI:

    # The authpriv file has restricted access and is signed with KSI
    authpriv.*    action(type="omfile" file="/var/log/secure"
      sig.provider="ksi_ls12"
      sig.syncmode="sync"
      sig.hashFunction="SHA2-256"
      sig.block.levelLimit="8"
      sig.block.timeLimit="0"
      sig.aggregator.url=
        "http://tryout.guardtime.net:8080/gt-signingservice"
      sig.aggregator.user="rsmith"
      sig.aggregator.key="secret"
      sig.keepTreeHashes="off"
      sig.keepRecordHashes="on")

Note that all parameter values must be between quotation marks!

See also

Help with configuring/using `Rsyslog`:

- Mailing list - best route for general questions
- GitHub: rsyslog source project - detailed questions, reporting issues that are believed to be bugs with `Rsyslog`
- Stack Exchange (View, Ask) - experimental support from rsyslog community

See also

Contributing to `Rsyslog`:

- Source project: rsyslog project README.
- Documentation: rsyslog-doc project README