Generate RSA-SHA1 signature based off of a string and private key

[SanjivMeher]

I am working on a JIRA integration from Servicenow and the authentication I want to use is oAuth 1.0. As servicenow doesnt support oAuth 1.0, I am writing custom code to make it work.

I have the access token, consumer id etc, and I am trying to generate a signature, with a private key and a string I have.

Is there a function which can generate the signature using RSA-SHA1 algorithm?

I know I can generate the HMAC SHA1, but RSA-SHA1 is not supported

var mac = new CertificateEncryption();
var signature = mac.generateMac(pkey, "RSA-SHA1", signatureBaseString);

[Sashi K1]

For Global reference --> 

var gce = new GlideCertificateEncryption;
gce.sign("<sys_id>", "", "<pwd>", "SHA1withRSA", "sign this data");

refer --> https://docs.servicenow.com/bundle/paris-application-development/page/app-store/dev_portal/API_reference/GlideCertificateEncryption/concept/c_GlideCertificateEncryptionAPI.html#

[Sashi K1]

Hey Sanjeev

Could you share the OpenSSL to export pkcs8 to pkcs12? When I tried to export and use from sys_certificate, I get the following error

Key must not be null: java.security.InvalidKeyException: Key must not be null: sun.security.rsa.RSAKeyFactory.engineTranslateKey(RSAKeyFactory.java:182)

Not sure whats going wrong. Could you share openssl command used to covert? 
When I attached to sys_certificate table, I see success message when used Validate cert UI action

Thanks
Sashi

[SanjivMeher]

I have documented the steps

• Generate certificates in Servicenow supported format

Now here comes another problem. ServiceNow does not support pkcs8. But it does support pkcs12 and jks. So what we would like to do is convert the certificates to p12 file. Instructions in step 1, generates following files. Jira_privatekey.pem, jira_publickey.pem and jira_privatekey.pcks8.

To generate the p12, you need the jira_privatekey.pem and jira_publickey.pem file. Create a copy of jira_privatekey.pem, which will only have the private key (jira_privatekey_copy.pem). Add the public key from jira_publickey.pem to the same file after the RSA Private Key section as shown below.

-----BEGIN RSA PRIVATE KEY-----

<Private Key>

-----END RSA PRIVATE KEY-----

-----BEGIN CERTIFICATE-----

<Public Key>

-----END CERTIFICATE-----

Then run the following command to generate the pkcs file.

openssl pkcs12 -export -in jira_privatekey_copy.pem -out jira_privatekey.p12

[Sashi K1]

Thank you Sanjeev, once we export the .p12 to sys_certificate, you did mention to use following code

var ce = new CertificateEncryption();
ce.sign("sysid of the certificate", "1", "", "SHA1withRSA", "datastring");

Question is on the datastring. What is the correct format of the datastring that would sign the Rest message and headers

Is that datastring is a rest end point and headers together? could you give me example?

[SanjivMeher]

Below link should help you understand

http://consumingrestapis.github.io/chapter-4/4.1-oauth-1.0.html

Below is a snapshot of what i did

signatureBaseString += encodeURIComponent("oauth_consumer_key="+consumerKey+"&");

signatureBaseString += encodeURIComponent("oauth_nonce="+nonce+"&");

signatureBaseString += encodeURIComponent("oauth_signature_method="+signatureMethod+"&");

signatureBaseString += encodeURIComponent("oauth_timestamp="+timestamp+"&");

signatureBaseString += encodeURIComponent("oauth_token="+accessToken+"&");

signatureBaseString += encodeURIComponent("oauth_token_secret="+verificationCode+"&");

signatureBaseString += encodeURIComponent("oauth_version=1.0");

var ce = new CertificateEncryption();

// For PKCS

var signature = ce.sign("<sys id of the certificate>", "1", "", "SHA1withRSA", signatureBaseString);