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CentOS 5.x

The short version:

Is there a way to change the encoding format for an existing CSR "Country Code" field from UTF8 to Printable String?

The long version:

I've got a CSR generated from a product using standard java security providers (jsse/jce). Some of the information in the CSR uses UTF8 Strings (which I understand is the preferred encoding requirement as of December 31, 2003 - RF 3280).

The certificate authority I'm submitting the CSR to explicitly requires the Country Code to be specified as a PrintableString. My CSR has it listed as a UTF8 string.

I went back to the latest RFC - http://www.ietf.org/rfc/rfc5280.txt. It seems to conflict specifically on countryName. Here's where it gets a little messy...

The countryName is part of the relative DN. The relative DN is defined to be of type DirectoryString, which is defined as a choice of teletexString, printableString, universalString, utf8String, or bmpString. It also more specifically defines countryName as being either alpha (upper bound 2 bytes) or numeric (upper bound 3 bytes). Furthermore, in the appendix, it refers to the X520countryName, which is limited to be only a PrintableString of size 2.

So, it is clear why it doesn't work. It appears that the certificate authority and Sun/Java do not agree on their interpretation of the requirements for the countryName. Is there anything I can do to modify the CSR to be compatible with the CA?

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@ChrisS Sorry, that was poor terminology on my part. They want the Country Code to be specified in printableString format. –  Mike B Aug 29 '12 at 20:48

1 Answer 1

up vote 1 down vote accepted

Figured it out. Here are the basic steps:

1) Open the original CSR and copy the base64 data between the “——-BEGIN CERTIFICATE REQUEST——-” and “——-END CERTIFICATE REQUEST——-” markers.

2) Put this data into a base64 decoder and save the output as a binary file. There are a variety of online services that can do this or if you prefer there are local tools as well.

3) Download/install a hex editor. Use it to open the decoded binary file.

4) Look for two values right before the countryName:

0C
02

5) Edit the value 0C (UTF8String) and change it to 13(Printablestring)

6) Save the changes and use a base64 encoder to encode it back to base64.

7) Add the base64 data back in between the “——-BEGIN CERTIFICATE REQUEST——-” and “——-END CERTIFICATE REQUEST——-” markers.

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