Verify Signed Email

Ruby script to load an signed email and verify the digital signature. The digital certificate used for signing is also retrieved and checked.

Download Ruby Programming Example Scripts

# file: VerifySignedEmail.rb

# Ruby script to verify the signature on a signed email.
#
# This example will load a signed email from a .eml file and demonstrate
# how to determine that the signature is valid.

# (Chilkat email objects can also be created by downloading email from 
# a POP3 server, an IMAP server (using Chilkat IMAP) or loading
# directly from a MIME string.)

# When a Chilkat email object is created, the security layers 
# (signature and/or encryption) are automatically "unwrapped".  
# This happens when an email is loaded from a MIME string, a .eml file, 
# or downloaded from a POP3/IMAP server.

# The result is that your program is always working with an email 
# that is in an unsigned and unencrypted state.  There are properties and
# methods that allow you to determine if the email was originally signed
# and/or encrypted, whether it was successfully verified and/or decrypted,
# and what digital certificates were used.

require 'chilkat'

# Create an instance of the mailman object for unlocking
mailman = Chilkat::CkMailMan.new()
mailman.UnlockComponent("anything for 30-day trial")

# Load a digitally signed email from a .eml
email = Chilkat::CkEmail.new()
success = email.LoadEml("signed_email.eml")
if not success
	email.SaveLastError("lastError.txt");
else
	# Was this email signed?
	if (email.get_ReceivedSigned()) then
		print "This email was signed!\n"
		
		# Was the signature verified?  This check is only meaningful if the
		# email was signed (i.e. ReceivedSigned is true)
		if (email.get_SignaturesValid()) then
			print "The digital signature is valid\n"
			
			# Get the digital certificate used for signing.
			cert = email.GetSignedByCert()
			
			# Show the certificate SubjectDN
			subjectDN = Chilkat::CkString.new()
			cert.get_SubjectDN(subjectDN)
			print "certificate SubjectDN:\n  [" + subjectDN.getString() + "]\n"
			
			# Is the certificate valid in all ways?
			if (cert.get_Revoked()) then
				print "Certificate is revoked!\n"
			end
			if (cert.get_Expired()) then
				print "Certificate is expired!\n"
			end
			if (!cert.get_SignatureVerified()) then
				print "Certificate's signature not verified!\n"
			end
			if (!cert.get_TrustedRoot()) then
				print "Certificate's root authority is not trusted!\n"
			end
			
		else
			print "The signature is NOT valid!\n"
		end
	end
end