Encrypt file using X509 Certificate

[i11usive]

I'm trying to encrypt a file using a X509 certificate. I'm trying using OPENSSL - command as follows:

 

openssl rsautl -encrypt -pubin -inkey receiver.crt -in my_infile.txt -out my_outfile.txt

 

However I can't seem to get this to work - it keeps coming up with "Unable to load publick key". Can anyone point me in the right direction to get this done? I'm sick of looking at visited links on Google trying to find a solution.

 

Thanks in advance.

[+BudMan MVC]

where did you get the cert, you don't seem to have any path specified in in your command.  Can you PM the cert and I will encrypt a text file for you showing example commands, etc..

 

what version of openssl are you using - this is on linux/windows - what flavor?

 

example on ubuntu 14.04.2

 

user@ubuntu:~$ openssl version
OpenSSL 1.0.1f 6 Jan 2014

 

do you have a CA setup?  Or did someone send you this x509?

[i11usive]

Thanks for the response. The cert has been issued by the US IRS - the link for which is https://www.ides-support.com/Downloads/encryption-service_services_irs_gov.crt

 

I'm running the OPENSSL on Windows - version 1.0.2a. I've managed to get this done before, but can't figure out for the life of me how to do it again. Of course, this time round I'm taking detailed notes.

 

All help appreciated.

[+BudMan MVC]

you sure that is the crt your using for encryption.  I grabbed that crt with wget and then looking at its details

 

[pre]

user@ubuntu:~/myCA$ openssl x509 -in gov.crt -text -noout

Certificate:

    Data:

        Version: 3 (0x2)

        Serial Number: 1355950258 (0x50d228b2)

    Signature Algorithm: sha256WithRSAEncryption

        Issuer: C=US, O=Entrust, Inc., OU=See www.entrust.net/legal-terms, OU=© 2012 Entrust, Inc. - for authorized use only, CN=Entrust Certification Authority - L1K

        Validity

            Not Before: Oct 16 18:44:59 2014 GMT

            Not After : Dec 17 02:12:19 2018 GMT

        Subject: C=US, ST=District of Columbia, L=Washington, O=United States Department of Treasury - IRS, CN=encryption-service.services.irs.gov

        Subject Public Key Info:

            Public Key Algorithm: rsaEncryption

                Public-Key: (2048 bit)

                Modulus:

                    00:e2:17:21:32:1e:7e:ee:13:ab:c1:46:1b:cc:f5:

                    c8:bf:e8:11:53:1c:89:52:d4:c8:71:7a:33:85:5f:

                    41:5f:f1:72:f9:dd:21:60:ba:cf:34:bc:07:37:d6:

                    be:60:f2:10:88:b5:b3:98:43:69:d9:57:08:31:ae:

                    77:ca:07:be:5c:30:5d:e5:22:85:ed:7c:db:2d:d9:

                    73:74:9d:44:47:ee:a5:94:1c:61:b6:d8:67:1f:9b:

                    11:bf:34:1d:c2:76:b0:02:b4:17:0c:2f:70:c5:ae:

                    52:54:8f:49:40:ee:84:e1:26:bb:83:bc:26:88:9d:

                    49:ba:58:cc:1a:ab:8e:0b:ac:e5:38:2e:46:67:43:

                    f6:5c:1e:55:b1:c2:6e:8e:98:a9:c5:1d:02:5c:68:

                    8d:43:6f:99:ea:02:ce:70:6b:24:39:44:7a:3e:73:

                    a6:0d:01:e6:d7:17:d6:1b:ad:b9:6a:ca:64:f0:68:

                    24:2b:9d:04:1b:0b:fe:8e:df:c9:cc:cb:58:06:60:

                    0c:3c:01:83:1e:3a:12:88:67:2b:8c:9a:8c:36:ed:

                    da:b5:7d:a2:f0:ec:39:d3:20:89:e4:d7:c1:e5:4f:

                    bb:53:b1:db:1f:93:a5:1b:b7:6f:01:8e:14:3e:e3:

                    df:3a:9d:2d:9f:2d:0e:df:fa:ab:89:3c:4f:54:84:

                    d3:f9

                Exponent: 65537 (0x10001)

        X509v3 extensions:

            X509v3 Key Usage:

                Digital Signature, Key Encipherment

            X509v3 Extended Key Usage:

                TLS Web Server Authentication, TLS Web Client Authentication

            X509v3 CRL Distribution Points:

                Full Name:

                  URI:http://crl.entrust.net/level1k.crl

            X509v3 Certificate Policies:

                Policy: 2.16.840.1.114028.10.1.5

                  CPS: http://www.entrust.net/rpa

                Policy: 2.23.140.1.2.2

            Authority Information Access:

                OCSP - URI:http://ocsp.entrust.net

                CA Issuers - URI:http://aia.entrust.net/l1k-chain256.cer

            X509v3 Subject Alternative Name:

                DNS:encryption-service.services.irs.gov

            X509v3 Authority Key Identifier:

                keyid:82:A2:70:74:DD:BC:53:3F:CF:7B:D4:F7:CD:7F:A7:60:C6:0A:4C:BF

            X509v3 Subject Key Identifier:

                C3:92:3E:9C:84:E4:63:50:CA:8A:FE:A2:27:67:BC:2C:7E:DB:5F:05

            X509v3 Basic Constraints:

                CA:FALSE

    Signature Algorithm: sha256WithRSAEncryption

         52:5d:9e:13:6c:f0:ce:91:b8:ca:40:59:05:b7:4a:0d:0f:e2:

         e3:88:1e:b8:50:92:56:ec:68:e2:bc:67:3a:ba:7e:7e:8c:af:

         e3:16:24:5b:89:95:e0:be:f8:94:f6:8b:39:d5:dc:7d:eb:e9:

         8d:62:be:04:6b:3e:1d:4a:2e:3c:4c:6e:8b:58:a6:0c:0c:2c:

         4f:4b:36:c4:45:5a:c2:33:fd:80:54:0d:19:a0:07:64:6e:11:

         8b:c6:d5:1e:bc:d2:16:13:37:d9:4e:96:a0:23:23:a1:7f:e5:

         39:34:b1:76:c1:56:7e:ac:21:39:2d:46:f9:f6:02:59:62:a5:

         af:f1:23:a1:27:af:ea:8e:0e:a8:15:a9:6a:a9:c4:76:b1:4f:

         c5:24:d2:11:0f:e1:de:ba:b4:24:26:b9:8b:a8:9c:7d:d9:2e:

         7d:18:76:90:e2:5d:49:34:3a:8b:0c:13:bf:16:36:36:34:f7:

         9d:68:e4:44:d8:71:9e:3e:af:78:ad:0d:f0:d8:f7:f2:91:40:

         da:33:1a:d7:62:ba:28:57:6a:95:68:19:65:e2:a4:65:3a:08:

         8a:f8:4a:df:20:b4:08:b4:69:bc:4c:ec:71:e9:f6:66:5f:cc:

         10:4f:05:04:65:f1:34:12:2f:8e:c1:bd:b5:d9:5a:de:ff:e8:

         b5:c1:04:8f

user@ubuntu:~/myCA$

[/pre]

 

Looks like its suppose to be used as client auth.

 

      X509v3 extensions:

            X509v3 Key Usage:

                Digital Signature, Key Encipherment

            X509v3 Extended Key Usage:

                TLS Web Server Authentication, TLS Web Client Authentication

 

 

So your trying to encrypt a file with it to send where?  From what the extensions are on that key..

 

http://tools.ietf.org/html/rfc5280

The keyEncipherment bit is asserted when the subject public key is

used for enciphering private or secret keys, i.e., for key

transport. For example, this bit shall be set when an RSA public

key is to be used for encrypting a symmetric content-decryption

key or an asymmetric private key.

The dataEncipherment bit is asserted when the subject public key

is used for directly enciphering raw user data without the use of

an intermediate symmetric cipher. Note that the use of this bit

is extremely uncommon; almost all applications use key transport

or key agreement to establish a symmetric key.

That key is not really meant to encrypt a file with and send it too them..

[i11usive]

Thanks for the responses - managed to get it using:

 

openssl smime -encrypt -binary -aes-256-cbc -in my_infile.txt -out my_ourfile.txt receiver.crt

 

Sometimes a break away from the screen helps! Plus bouncing off you guys :-)

[+BudMan MVC]

that is not really what the crt is meant for...

From looking at the extensions on that crt, it does not look to be intended for smime...

http://tools.ietf.org/html/rfc3850

4.4.4. Extended Key Usage Extension

The extended key usage extension also serves to limit the technical

purposes for which a public key listed in a valid certificate may be

used. The set of technical purposes for the certificate therefore

are the intersection of the uses indicated in the key usage and

extended key usage extensions.

For example, if the certificate contains a key usage extension

indicating digital signature and an extended key usage extension

which includes the email protection OID, then the certificate may be

used for signing but not encrypting S/MIME messages. If the

certificate contains a key usage extension indicating digital

signature, but no extended key usage extension then the certificate

may also be used to sign but not encrypt S/MIME messages.

If the extended key usage extension is present in the certificate

then interpersonal message S/MIME receiving agents MUST check that it

contains either the emailProtection or the anyExtendedKeyUsage OID as

defined in [KEYM]. S/MIME uses other than interpersonal messaging

MAY require the explicit presence of the extended key usage extension

or other OIDs to be present in the extension or both.

From looking at that cert, its meant for client auth, and not really meant as means of sending encrypted messages via smime.. While it has the digital signature ext.. It makes no mention of other email related use, and clearly states the client auth ext.. So while you could use it to sign a email, clearly it should not be used for encryption from my looking at it.