About

A CSR is signed by the private key corresponding to the public key in the CSR. This check verifies the signature on the CSR is valid. An invalid signature indicates that the CSR has been modified since it was created or the public key in the CSR doesn't correspond to the private key used to sign it.

This check checks if the CSR's name contains a field with no value. For example, the CSR Decoder would issue a warning about the name given below because the locality field is present, but has no value.

CN=www.acme.com, O=acme, L=, C=gb

The reason for this warning is that some CAs may reject CSRs that contain fields with empty values.

Checks for weak RSA keys generated by Debian-based systems. It uses the dowkd blacklist, which may be incomplete.

This page contains CSRs and certificates with known weak keys. Please let us know if it fails to identify a CSR or certificate you know to have weak key.

In May 2008, the Debian team announced that Luciano Bello had discovered a vulnerabilty in the Debian OpenSSL package. The impact was that all SSL and SSH keys generated on Debian-based systems (including Ubuntu) released between September 2006 and May 13th 2008 may be affected. The Debian Security Team disclosed this vulnerability in Debian Security Advisory 1571. The best resource on this vulnerability is the Debian Wiki. We have also written about this in our CSR FAQ.

Checks RSA and DSA keys are at least 2048 bits and EC keys are at least 224 bits

About Cert Logik

What is Cert Logik?

Cert Logik is a collection of PKI and SSL products developed by Red Kestrel Consulting Limited. We've combined a CSR Decoder and X.509 Certificate Decoder into a single decoder to make decoding simpler. We've developed an SSL Checker that connects to your website and checks the installation of your SSL certificate.. We have also developed a number of PKI and SSL standalone commercial tools.

About CSR and Certificate Decoder

Objects it can Decode

The CSR and Certificate Decoder can decode the following types of objects:

X.509 Certificates
SSL Certificates
PKCS#7 encoded Certificate Chains
CSRs or PKCS#10 Requests
Some CMS objects

Certificate Checks

The Certificate Decoder checks the following:

Certificate does not use a weak key
Certificate has not expired
Key size is at least 2048 bits
The signature algorithm is strong

CSR Checks

The CSR Decoder checks the following:

CSR does not use a weak key
CSR signature is valid
Key size is at least 2048 bits
The Subject field does not contains empty values

About Red Kestrel Consulting

Red Kestrel Consulting Limited is an IT security consultancy founded in 2004 by Phil Ratcliffe. Based in Staffordshire in the UK, Red Kestrel provide security consultancy and software development services to various clients including banks, governments and software companies. We have experience in many areas of IT security including but not limited to: PKI, cryptography, secure email, smart cards, biometrics and secure application development.