---
name: "certpatch"
section: "8"
platform: "linux"
package: "isakmpd"
version: "20041012-8"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/certpatch"
---

# certpatch(8)

add subjectAltName identities to X.509 certificates

## NAME

**certpatch** – add subjectAltName identities to X.509 certificates

## SYNOPSIS

**certpatch** \[**-t** *identity-type*\] **-i** *identity* **-k** *signing-key* *input-certificate* *output-certificate*

## DESCRIPTION

**certpatch** alters PEM-encoded X.509 certificates by adding a subjectAltName extension containing an identity used by the signature-based authentication schemes of the ISAKMP protocol. After the addition the certificate will be signed once again with the supplied CA signing key.

The options are as follows:

- **-t** *identity-type*

  If given, the **-t** option specifies the type of the given identity. Currently ip, fqdn, and ufqdn are recognized. The default is ip.

- **-i** *identity*

  The **-i** option takes an argument which is the identity to put into the subjectAltName field of the certificate. If the identity-type is ip, this argument should be an IPv4 address in dotted decimal notation.

- **-k** *signing-key*

  The **-k** option specifies the key used for signing the certificate once the subjectAltName extension has been added. The key is specified by the filename where it is stored in PEM format.

## SEE ALSO

[isakmpd(8)](/isakmpd/8.md), [ssl(8)](/ssl/8.md)