SecKeyGeneratePair returns errSecUnimplemented

Question

Im attempting to implement an RSA encryption algorithm into my iOS app, but when I attempt to generate a public and private key pair, the function returns me the errSecUnimplemented error. I am using the 5.1 SDK and targeting 5.1 at the moment.

Can I not use this function, or did I set up something wrong in attempting to generate the pair?

Here is my code for the key generation:

SecKeyRef publicKey, privateKey;
CFDictionaryRef parameters;
const void* keys[] = {kSecAttrKeyType, kSecAttrKeyTypeRSA};
int keySize = 1024;
const void *values[] = {kSecAttrKeySizeInBits, &keySize};

parameters = CFDictionaryCreate(kCFAllocatorDefault, keys, values, 2, NULL, NULL);
OSStatus ret = SecKeyGeneratePair(parameters, &publicKey, &privateKey);
if ( ret == errSecSuccess )
{
    NSLog(@"Key success!");
}
else 
{
    NSLog(@"Key Failure! %li", ret);
}

NSProgrammer · Accepted Answer · 2012-05-16T13:28:34.380

9

I've revised it to just complete the solution for you. 1) You need to use a CFNumberRef and not a pointer to an int for the numerical value. 2) The values need to be the values, the keys need to be the keys - you were mixing a key and value in each of "keys" and "values".

SInt32 iKeySize = 1024;
CFNumberRef keySize = CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &iKeySize);
const void* values[] = { kSecAttrKeyTypeRSA, keySize };
const void* keys[] = { kSecAttrKeyType, kSecAttrKeySizeInBits };
CFDictionaryRef parameters = CFDictionaryCreate(kCFAllocatorDefault, keys, values, 2, NULL, NULL);

SecKeyRef publicKey, privateKey;
OSStatus ret = SecKeyGeneratePair(parameters, &publicKey, &privateKey);
if ( ret == errSecSuccess )
    NSLog(@"Key success!");
else 
    NSLog(@"Key Failure! %li", ret);

edited May 16 '12 at 13:28

answered May 11 '12 at 23:31

NSProgrammer

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I get the following error with ARC enabled: `Use __bridge_retained to make an ARC object available as a +1 'CFTypeRef' (aka 'const void *')` Last time I tried to use a `__bridge` cast everything went haywire, is this a simpler, but safe case to do so? – Dan F May 14 '12 at 13:27
And even if I do a `__bridge_retained` cast, I still get the -4 error – Dan F May 14 '12 at 13:28
Edited to be complete. You should be good to go (so long as I didn't leave any typos). – NSProgrammer May 15 '12 at 14:56
I get a warning with your code because `values` is of type `void*` not `void**`, and if I make it into `const void* values[]` i get a bad access exception, and still the -4 error if I leave it as just a `const void *` – Dan F May 15 '12 at 15:13
Apologies, you should pass the ref to your keys and values, edited – NSProgrammer May 15 '12 at 19:33
Those still aren't the right types. `CFDictionaryCreate` is looking for two `const void **`, and `keys` by itself is a `const void **` adding the reference to it, you're making it a `const void ***`, and in your latest edit, `values` is still written as just a `const void *`, not a `const void *[]` – Dan F May 15 '12 at 19:36
Oh man... I see it now. I didn't put the array parens for one of the declarations. I should mention I'm doing this all on my iPhone. – NSProgrammer May 15 '12 at 23:02
I tried that combination, and that is how I end up with an EXC_BAD_ACCESS exception being thrown on `SecKeyGeneratePair` – Dan F May 16 '12 at 13:07
That's what I get for not checking my work with a compiler. values needed the CFNumberRef itself, not a reference to it. Code updated... – NSProgrammer May 16 '12 at 13:29
Ah HA! Finally success! Thank you for all your help, I searched for quite a while to find sample code for this method, but just nothing existed anywhere... – Dan F May 16 '12 at 13:58
Yay! The power of crowd sourcing and persistence! :) – NSProgrammer May 16 '12 at 14:01
For those using the example code here, 1024 bit RSA keys aren't considered secure anymore, you should use 2048 or 4096 bit keys instead. – Michael Barnwell Jan 30 '18 at 13:51
Do we have this in swift? – Mike May 29 '20 at 17:20

score 0 · Answer 2 · answered May 15 '12 at 12:01

0

Shouldn't this be:

const void* keys[] = {kSecAttrKeyType, kSecAttrKeySizeInBits};
int keySize = 1024;
const void *values[] = {kSecAttrKeyTypeRSA, &keySize};

i.e., the keys should be the keys of the dict and the values the values, currently you have one (key,value) pair in keys and one in values.

answered May 15 '12 at 12:01

Arno Bakker

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4

I get a bad access exception when I do it this way, even with setting the key size as nob outlined above – Dan F May 15 '12 at 13:01
Perhaps http://www.iphonedevsdk.com/forum/iphone-sdk-development/7339-rsa-encryption.html helps. – Arno Bakker May 23 '12 at 11:21

score 0 · Answer 3 · edited Oct 21 '12 at 08:58

0

Using kCFAllocatorSystemDefault instead of kCFAllocatorDefault return errSecSuccess.

edited Oct 21 '12 at 08:58

user

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answered Jun 15 '12 at 20:43

Adrian Procopenco

1

SecKeyGeneratePair returns errSecUnimplemented

3 Answers3

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