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I have searched on several topic but I don't really find what I need. The problem is : I'd like to sign file with digital certificate from my own writted program (desktop or web). Then I want to know:

  1. If I can do that with CA certificate.
  2. Which CA can issue me certificate I can use in my program. I mean CA certificate file with method to access to Algorithm, Key, and also to send verification request to server? A kind of API?
  3. Does this kind of certificate exist ? Can I found it for free?
Tonechas
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Bool
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1 Answers1

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For as long as I understood your questions correctly, find below my answers:

1 - You can generate get you Digital Certificate by generating you key pair and then sign your public key by any CA (either your own CA or any Publicly trusted CA)

2 - You can make a request to a CA to get your Digital Certificate. Guessing that you want a publicly trusted certificate than you can use a wide range of CA's. I would suggest you to check the Let's Encrypt project, they release free certificates. Using your digital certificate is a matter of your implementation. Basically you need to know what do you want to achieve with it (like confidentiality, authentication, integrity..). Usually you want to implement SSL to achieve any of these features. For signing documents you need to encrypt with your private key associated with the public key that was used to get the digital certificate.

3 - As I also stated in the second answer, Yes there are free options for publicly trusted digital certificates

Trim Kadriu
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  • OK.Thank, i'm going to check if i' m satisfied, maybe it remains something. – Bool Feb 11 '17 at 15:58
  • 1) Let's suppose i install Let's Encrypt SSL certificate. Can i use it for signing file? I' d like to know if it meets specification of this question answer : http://stackoverflow.com/questions/9691521/can-ssl-cert-be-used-to-digitally-sign-files , About KeyUsage, CodeSigning and extendedKeyUsage 2) if it doesn't, which free CA can give this kind of certificate? – Bool Feb 12 '17 at 20:41