I am wondering whether I can use a shared secret key established between two clients as the HMAC key too.
I saw that there is a problem when it is used as a CBC-MAC but I haven't found any evidence it is bad practice for HMACs.
Thanks,
Vladimir
I believe it is currently in the category of "seems probably OK, but why take the risk?".
Best practice is to have each side generate two new keys from the shared secret key:
encryption-key := HMAC(shared-key, "Encryption Nonce")
hmac-key := HMAC(shared-key, "Authenticity Nonce")
As caf eluded to. One of the correct ways to do this is to hash the shared-secret-key with some extra data.
For Example:
enc-key = HASH(shared-key || 1)
hmac-key = HASH(share-key || 2)
This has the benefit of not needing to transfer 2 extra nonces as well as being easy to implement.
I would NOT use the same key in different functions (enc + hmac). That is asking for trouble and a bad idea.
Related
I am trying to get some secret objects from my cluster using the k8s go client library as follows
secret, err := clientset.CoreV1().Secrets("mynamespace").Get("name-of-my-secret", metav1.GetOptions{})
This worked well as long as I had to get just one object.
I have a case now where I need to fetch several such secret objects, however this now has to be done based on labels. (i.e. fetch all such secret objects matching the foo=someprovider.someurl.com/path1=value1 label)
I don't see however in the relevant docs a way to pass label selectors to the GetOptions struct that I assume performs such kind of filtering.
Any suggestions on how to select (potentially multiple) such resources based on labels?
clientset.CoreV1().Secrets("").List(context.TODO(), metav1.ListOptions{LabelSelector: "k8s-app=kube-proxy"})
I'm new to Aerospike and am probably missing something fundamental, but I'm trying to see an enumeration of the Keys in a Set (I'm purposefully avoiding the word "list" because it's a datatype).
For example,
To see all the Namespaces, the docs say to use SHOW NAMESPACES
To see all the Sets, we can use SHOW SETS
If I want to see all the unique Keys in a Set ... what command can I use?
It seems like one can use client.scan() ... but that seems like a super heavy way to get just the key (since it fetches all the bin data as well).
Any recommendations are appreciated! As of right now, I'm thinking of inserting (deleting) into (from) a meta-record.
Thank you #pgupta for pointing me in the right direction.
This actually has two parts:
In order to retrieve original keys from the server, one must -- during put() calls -- set policy to save the key value server-side (otherwise, it seems only a digest/hash is stored?).
Here's an example in Python:
aerospike_client.put(key, {'bin': 'value'}, policy={'key': aerospike.POLICY_KEY_SEND})
Then (modified Aerospike's own documentation), you perform a scan and set the policy to not return the bin data. From this, you can extract the keys:
Example:
keys = []
scan = client.scan('namespace', 'set')
scan_opts = { 'concurrent': True, 'nobins': True, 'priority': aerospike.SCAN_PRIORITY_MEDIUM }
for x in (scan.results(policy=scan_opts)): keys.append(x[0][2])
The need to iterate over the result still seems a little clunky to me; I still think that using a 'master-key' Record to store a list of all the other keys will be more performant, in my case -- in this way, I can simply make one get() call to the Aerospike server to retrieve the list.
You can choose not bring the data back by setting includeBinData in ScanPolicy to false.
After I imported SJCL AES key using new sjcl.cipher.aes(rawKey), how can I get rawKey value back from the key instance?
As far as I know it is not easily possible.
Looking at the code, the key is immediatly transformed using the S-Box. The result ist stored in this._key, so you could get that result and then use the reverse S-Box to restore rawKey. This should work, but just storing the key in a variable is of course way simpler.
Ok after experimenting a little bit I found out that resin was calling my AbstractAuthenticator implementation "authenticate" method that takes an HttpDigestCredentials object instead of DigestCredentials (still don't know when is called each one of them) the problem is that HttpDigestCredentials doesn't have a getDigest() method, instead it has a getResponse() method which doesn't return a hash or at least not a comparable one.
After creating my own hash of [[user:realmassword] [nonce] [method:uri]] the hash is very different, in fact I think getResponse() does not return the digest but maybe the server response to the browser?.
Any way this is my debugging log :
USER:user:PASSWORD:password:REALM:resin:METHOD:GET:URI/appe/appe.html:NONCE:HsJzN+j+GQD:CNONCE:b1ad4fa1ba857cac88c202e64528bc0c:CLIENTDIGEST:[B#5dcd8bf7:SERVERDIGEST:I4DkRCh21YG2Mk14iTe+hg==
as you can see both the supposed client nonce is very very different from the server generated nonce, in fact the client nonce doesn't look like a MD5 hash at all.
Please has someone does this before? is there something missing in the HttpDigestCredentials? I know digest is barely used.
Please, I know about SSL but I can't have an SSL certificate just yet so don't tell me "Why don't you use SSL". ;)
Update:
Not sure if was the right thing to do but, as I read before Resin uses base64 format for hashes so I used apache commons-codec-1.6 to use encodeBase64String() method and now the hashes look alike but they are no the same.
I tried both passwordDigest.getPasswordDigest(a1+':'+nonce+':'+a2); passwordDigest.getPasswordDigest(a1+':'+nonce+':'+ncount+':'+cnonce+':'+qop+':'+a2);
and none of them gives the same hash as the one from HttpDigestCredentials.
Ok I finally made it . Weird subject Huh, only two views?
First, digest authentication makes use of user, password, realm, nonce, client_nonce, nonce_count, method, qop, and uri. Basically it uses the full digest spec. So in order to calculate the hash one must calculate it with all the whistles. Is just a matter of calling the get method for each one of the variables from HttpDigestCredentials except for user and password. The user will come in the form of a Principal and the password you must look for it yourself in your DB (in my case a DB4O database).
Then you must create a PasswordDigest object, that will take care of generate a hash with the getPasswordDigest() method, but first one must set the format to hex with passwordDigestObject.setFormat("hex").
There is one for the HA1 getPasswordDigest(user,password,realm) and there is another getPasswordDigest() method that takes just one string and one can use it to generate the rest of the hashes, both HA2 and with the previous hashed HA1 the final hash, of course with the nonce nonce_count client_nonce and qop, of course each one separated by a semicolon.
Then it comes the tricky part, although resin works with base64 encoding for digest when you call the getResponse() method from HttpDigestCredentials it returns a byte array (which is weird) so in order to compare it with your hash what I did was use the Hex.encodeHexString() method from org.apache.commons.codec.binary.Hex and pass the HttpCredentialsDigest getResponse() return value, and that will give a nice hex String to compare.
I was doing it the other way around, I was using the Base64 hash from PasswordDigest and converting the HttpDigestCredentials hash to Base64 and the resulting string were never the same.
How to encrypt a nsstring and store it in a file, and how to decrypt the same.
Please suggest me wat api's i shld use...
This is the function i used for encryptiong.
DES_cfb64_encrypt( ( unsigned char * ) pchInputData, ( unsigned char * ) pchOutCipher,
size, &schedule, &ParityKey, &no, DES_ENCRYPT );
I had to convert this to base64 so that i can store it in a file.
pstrResult = Base64encoding(size,( unsigned char * )pchOutCipher);
You can use gpgme
If you only need to support 10.5 or higher you can use the CommonCryptor API. The first comment to this post shows an example category for encrypting/decrypting NSData's:
http://iphonedevelopment.blogspot.com/2009/02/strong-encryption-for-cocoa-cocoa-touch.html
While not an API call, you could implement a simple XOR cipher. This is quick and simple to implement and depending on the characteristics of your string (i.e. if it is of fixed length) can be very secure. If you have a variable length string XOR encryption may not be secure enough depending on your needs. Have a look at the Wikipedia article.
If you are storing a password first decide whether or not you need to re-use the password or whether you just need to check that the user has entered the correct password.
If you just need to verify that the user has entered the correct password, then store the password using a hash, and compare the hash of the user input with the hash you have stored. If both hashes are equal, then the user has [probably] typed it correctly. See more information about hashes at Wikipedia.
If you need to re-use the password (i.e. for authenticating with other services, such as connecting to an Internet service), use Apple's Keychain service. If you are targeting the iPhone, then check out this related document.