(Ruby) RSA Sign String using Private Key of Certificate Type A3 (smart card / token)

Demonstrates RSA signing a string using the private key of a certificate type A3 (smart card, token).

Note: This is a Windows-only example.

Note: This example requires Chilkat v10.1.2 or greater.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# First get the A3 certificate that was installed on the Windows system.
certStore = Chilkat::CkCertStore.new()

thumbprint = "12c1dd8015f3f03f7b1fa619dc24e2493ca8b4b2"

# This is specific to Windows because it is opening the Windows Current-User certificate store.
bReadOnly = true
success = certStore.OpenCurrentUserStore(bReadOnly)
if (success != true)
    print certStore.lastErrorText() + "\n";
    exit
end

# Find the certificate with the desired thumbprint
# (There are many ways to locate a certificate.  This example chooses to find by thumbprint.)
json = Chilkat::CkJsonObject.new()
json.UpdateString("thumbprint",thumbprint)

cert = Chilkat::CkCert.new()
success = certStore.FindCert(json,cert)
if (success == false)
    print "Failed to find the certificate." + "\n";
    exit
end

print "Found: " + cert.subjectCN() + "\n";

rsa = Chilkat::CkRsa.new()

# Provide the cert's private key
bUsePrivateKey = true
success = rsa.SetX509Cert(cert,bUsePrivateKey)
if (success != true)
    print rsa.lastErrorText() + "\n";
    exit
end

# Return the RSA signature in base64 encoded form.
rsa.put_EncodingMode("base64")

# Sign the utf-8 byte representation of the string.
rsa.put_Charset("utf-8")

# You can also choose other hash algorithms, such as SHA-1.
sigBase64 = rsa.signStringENC("text to sign","SHA-256")
if (rsa.get_LastMethodSuccess() != true)
    print rsa.lastErrorText() + "\n";
    exit
end

print "Base64 signature: " + sigBase64 + "\n";