If we make the private key exportable (using -pe option in makecert), then in theory we have both an exportable private key and the public key (public key in certificate) -- which can be transferred or imported to another machine.
So, my question is, why do we still need to create the .pfx file (key exchange file, which contains private and public keys) -- making the private key exportable in certificate could do anything we want? Any scenarios pfx file could cover which making private key exportable in certificate could not achieve?
thanks in advance,
George
Is there a makecert command line you have found that will generate a certificate file that includes a private key? I never have. I have seen someone allude to the fact that there is a version of makecert that can produce .pfx files but also have never seen that.
That means at the very best you can create TWO files with makecert if you want a private key file. One for the certificate and one for the private key. You can copy both those files to another computer and import them using makecert.
The advantage of the .pfx certificate format is that you can combine the two files with the certificate and private key into one. This is more convenient and also means you can use the file with the .Net X509Certificate2 class for use with an SslStream.
Your pfx file can be password protected, that would add a layer of protection
The problem is, the X509 Certificate standard (the certificate) does not include the private key. The certificate contains the subject public key info (aka, the public key) and information about the holder of the private key, but the standard does not support including the private key. This is the basic idea of PKI - the certificate is the public info you share with the world, the private key is something you hold very securely.
Making a private key exportable in any mechanism (for example, makecert), means you are telling that product that the key can be exported. It doesn't specify the file format that you would use to store it. A pfx file is one way of storing the private key - it uses the PKCS 12 standard. Java Key Stores (*.jks) are another way to do the same thing. Most commerically supported standards have similar common features - they protect the private key by encrypting it. The encryption can be unlocked using a password. They couple the private key with the certificate that decribes it.
If you want to build a PFX file, you should have both x509 cert public key and private key file which you can generate using makecert command. PFX can be generated using PVk2PFX command which you can find Microsoft SDK installation directiory.
Related
A CSR is mainly created to create a certificate having trusted public key.
Before creating a CSR,
we create a private key
openssl genrsa -out key.pem 1024
and then use that private key(key.pem) to create a CSR(req.pem) request.
openssl req -new -key key.pem -out req.pem
Edit:
I see that a docker engine is installed with root certificate, server certificate & private used with CSR
What is the exact purpose of providing private key(key.pem as input) amidst submitting CSR? Because certificate is supposed to be signed with parent private key
Is private key(key.pem) required to generate corresponding public key amidst CSR creation?
or
Is private key(key.pem) used to encrypt the CSR and the resulting signature is appended to CSR?
The structure of a PKCS#10 certification request (RFC 2986) is, loosely described:
Request:
Info:
Version
Name
PublicKey
Attributes
SignatureAlgorithmIdentifier
Signature
The attributes are attributes for the request, where one if them could be attributes you are requesting for the resulting certificate.
The CA can respect as much, or as little, from the CSR as it chooses. StartSSL, for example, only read out the public key information, and discarded the remainder of the CSR -- everything else they needed was based on your request from their web UI and your account status.
In general, the CA isn't going to ignore the public key value, because if they asserted a new keypair for you they'd need to figure out how you were supposed to get the private key. So, the public key part needs to be present and correct. OpenSSL's command can get the public key value by reading the private key, then it can embed it in the CSR.
The second reason you need the private key is to sign the request. I'll assert that the main reason the request is signed is to force/strongly-suggest you save the private key at this stage, so you don't come back in a few minutes with a "please revoke this new certificate, I already lost the private key" request. The RFC (also) has this to say:
Note 2 - The signature on the certification request prevents an
entity from requesting a certificate with another party's public key.
Such an attack would give the entity the minor ability to pretend to
be the originator of any message signed by the other party. This
attack is significant only if the entity does not know the message
being signed and the signed part of the message does not identify the
signer. The entity would still not be able to decrypt messages
intended for the other party, of course.
I have a file with a certificate in it, and I have a file with a private key file in it.
if I run this command
certutil –MergePFX certfile.cer certfile.pfx
I get a pfx file that if I run with explorer, it runs the windows certificate import wizard. If I run through the wizard, I end up with the cert with the key in the windows trust store. Exactly what I need.
I'm trying to do this programatically.
The problem seems to be in the CertAddCertificateContextToStore function.
In the remarks it says:
The certificate context is not duplicated using CertDuplicateCertificateContext. Instead, the function creates a new copy of the context and adds it to the store. In addition to the encoded certificate, CertDuplicateCertificateContext also copies the context's properties, with the exception of the CERT_KEY_PROV_HANDLE_PROP_ID and CERT_KEY_CONTEXT_PROP_ID properties.
So certduplicatecertificatecontext very specifically will not copy the private key, and it seems that CertAddCertificateContextToStore doesn't either.
I have a HCRYPTPROV struct with my private key and I use CERT_KEY_CONTEXT_PROP_ID and CERT_KEY_PROV_HANDLE_PROP_ID (I tried them both) to CertSetCertificateContextProperty my certificate context, and then I store it in the windows trust store with CertAddCertificateContextToStore. And no matter what I try, the certificate goes in without the private key.
I'm verifying this with the certmgr tool that shows if a private key is attached, and I can also see it not work when I use that client certificate in a curl request I'm making.
Another thing I tried was this:
The last parameter to CertAddCertificateContextToStore is the handle to the copy of the context that is made. I figure the original context is the one I created where I read the certificate in from disk. This new certificate is the one tied to the actual on-disk store that certmgr reads.
So after I call CertAddCertificateContextToStore, I take the new cert and I add the private key, again via CertSetCertificateContextProperty, and then for good measure, I call CertControlStore to push the in-memory version of the context to disk. Still no effect. Every function call succeeds, but the private key never makes it to the windows trust store.
So in short, my question is what is the windows certificate import tool doing that I am not that will allow me to store a private key along with the certificate in the windows trust store?
I've found a handful of other questions and program examples and message boards dating back to 2002 and none are very explicit, and none of the code examples do exactly what I need, but I know I have all the pieces, they just don't yield the result.
I strongly believe that you set incorrect properties. You should set only CERT_KEY_PROV_INFO_PROP_ID context property in the CertSetCertificateContextProperty call to associate certificate with private key.
If you have a HCRYPTPROV handle, then you have all necessary information to construct CRYPT_KEY_PROV_INFO structure.
I need to write a method in Swift which uses a particular PRIVATE KEY to encrypt a timestamp using RSA. This is NOT used for authentication (rather it validates the client app to the server), I know that you would normally encrypt with a public key to ensure security.
I have a key:
-----BEGIN RSA PRIVATE KEY-----
MIICXAIBAAKBgQDIg+wteSjhalc1hSHEiUnz9X1pkrObCjaXMHqeSdfFQ/h5Q1Uh
...
o7wjoqFNxFnQMAYvkLzQZ7Y2jjfSJkaTVnhzJIZOfQ0=
-----END RSA PRIVATE KEY-----
And I need to encrypt a string using this particular key. I have written the Android application version of this app, but if I need to re-generate the keys specifically for iOS it's not a problem, but I would need this file for the Android version as well.
I have looked at the following web sites:
http://jslim.net/blog/2013/01/05/rsa-encryption-in-ios-and-decrypt-it-using-php/ Seems useful but it insists that the key be in a .der format - plus it's in Objective-C. Is it possible to generate a Key pair in both DER and PEM format, or convert between the two (using something like https://www.sslshopper.com/ssl-converter.html)?
https://github.com/henrinormak/Heimdall - but you cannot import a custom private key
https://github.com/ideawu/Objective-C-RSA/blob/master/RSA.m - seems long winded and is also in objective-c
One requirement is that all apps use the SAME key - it cannot be generated by each installation of the app. Also my Android app must be able to use the key as well (I am open to rethinking the Android version as leaving the key as a RAW file is not preferred for me).
Any help will be appreciated.
Other references checked:
How to encrypt a string with private key and decrypt with public key?
Using RSA public key to encrypt a string
I am reading about application code signing in iOS and I don't understand why both private and public key is together? What is the public key and certificate used for when you are signing the application with the private?
Xcode uses your digital identity to sign your application during the
build process. This digital identity consists of a public-private key
pair and a certificate. The private key is used by cryptographic
functions to generate the signature. The certificate is issued by
Apple; it contains the public key and identifies you as the owner of
the key pair.
Let's sum up the process:
You encrypt an hashed digest (like md5 or sha-1) of the executable of application with your private key. That's "signing".
Your users decrypt it with your public key (they have it because it's public) and check it against the executable. As long as your private key stays private, it's you who "signed" it. That's called "verifying".
What about the digital identity then:
You public key isn't public by itself, it must be somehow shared, "made public", and signed by the Certification Autority (hereby CA) too, (that's the CA encrypting it —or an hash of it— with their, one of their, magical mysterious private keys) this guarantees the sharing process hasn't been tampered with by a man in the middle.
So, public key and certificate (CA signature — CA encrypting your public key) identify you (as such are considered part of your "digital identity") and must reach the end user somehow (via a third party, embedded into the executable, you name the way)
The public key is needed so anyone can decrypt the application, and is hence included in the build.
I have a Public Key generated in JAVA.
I want to use this key and crypt the data using RSA and send it to the server.
How can I do that using the iPhone SDK?
Thanks
Unfortunately, iOS has no public APIs to deal with raw RSA keys.
There are two things you can do:
1) Instead of giving your app a Public Key, give your app a certificate instead. You can import the certificate with SecCertificateCreateWithData. Then create a trust with SecTrustCreateWithCertificates. Once you have the trust, you can extract the public key with SecTrustCopyPublicKey.
2) The other option is to include OpenSSL in your project. It has all the APIs you need, you can google for example code on how to work with RSA keys. This might be the simpler solution.
I have made available a script to easily build OpenSSL from source. You can grab it from:
http://github.com/st3fan/ios-openssl
If your public key is in modulus/exponent form, this question may help: Convert XML Dsig format to DER ASN.1 public key
I figured out how to binary-encode the modulus and exponent into the DER ASN.1 format that the SecKeyWrapper class of Apple's CryptoExercise project uses to import an external key.