Creating OpenSSH compatible key pa…

I’m trying that with this simplified piece of code:

CFMutableDictionaryRef privAttrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); CFDictionarySetValue(privAttrs, kSecAttrIsPermanent, kCFBooleanFalse); CFDictionarySetValue(privAttrs, kSecAttrLabel, CFSTR("[email protected]")); CFMutableDictionaryRef attrs = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks); CFDictionarySetValue(attrs, kSecAttrKeyType, kSecAttrKeyTypeRSA); CFDictionarySetValue(attrs, kSecAttrKeySizeInBits, CFSTR("4096")); CFDictionarySetValue(attrs, kSecPrivateKeyAttrs, privAttrs); CFErrorRef error = NULL; SecKeyRef privateKey = SecKeyCreateRandomKey(attrs, &error); if (privateKey) {     CFDataRef data = NULL;     OSStatus status = SecItemExport(privateKey, kSecFormatSSH, kSecItemPemArmour, NULL, &data);     if (status == errSecSuccess)     {         // ... save private key data đồ sộ a tệp tin ...     }     SecKeyRef publicKey = SecKeyCopyPublicKey(privateKey);     if (publicKey)     {         status = SecItemExport(publicKey, kSecFormatSSH, kSecItemPemArmour, NULL, &data);         if (status == errSecSuccess)         {             // ... save public key data đồ sộ a tệp tin ...         }         CFRelease(publicKey);     }     CFRelease(privateKey); } CFRelease(privAttrs); CFRelease(attrs); 

This seems đồ sộ create valid RSA key pair, which I can add đồ sộ the Keychain on creation if I choose đồ sộ (setting permanent attribute đồ sộ true), but the exporting operation doesn’t over up with files I expect. The PEM armour seems not đồ sộ be correct, the text representation of the key begins and ends with -----BEGIN/END RSA PRIVATE KEY----- as opposed đồ sộ -----BEGIN/END OPENSSH PRIVATE KEY----- and the key structure looks different in general. If I try đồ sộ show key fingerprint using

ssh-keygen -l -f

I get response that “ is not a key tệp tin. If I, for example, try đồ sộ upload the public key đồ sộ GitHub đồ sộ use for SSH connection, it’s rejected, because “key is invalid, you must supply a key in OpenSSH public key format."

I’d appreciate if anyone points out what I’m doing wrong and whether this is achievable with Security framework at all.

Thanks,

-- Dragan