//

 //  MYPrivateKey.m

 //  MYCrypto

 //

 //  Created by Jens Alfke on 4/7/09.

 //  Copyright 2009 Jens Alfke. All rights reserved.

 //

 #import "MYPrivateKey.h"

 #import "MYCrypto_Private.h"

 #import "MYDigest.h"

 #import <CommonCrypto/CommonDigest.h>

 #if !TARGET_OS_IPHONE

 #import "MYCertGen.h"

 #endif

 @implementation MYPrivateKey

 - (id) initWithKeyRef: (SecKeyRef)privateKey

 {

     self = [super initWithKeyRef: privateKey];

     if (self) {

         // No public key given, so look it up:

         MYSHA1Digest *digest = self._keyDigest;

         if (digest)

             _publicKey = [[self.keychain publicKeyWithDigest: digest] retain];

         if (!_publicKey) {

             // The matching public key won't turn up if it's embedded in a certificate;

             // I'd have to search for certs if I wanted to look that up. Skip it for now.

             Log(@"MYPrivateKey(%p): Couldn't find matching public key for private key! digest=%@",

                 self, digest);

             [self release];

             return nil;

         }

     }

     return self;

 }

 - (id) _initWithKeyRef: (SecKeyRef)privateKey

              publicKey: (MYPublicKey*)publicKey 

 {

     Assert(publicKey);

     self = [super initWithKeyRef: privateKey];

     if (self) {

         _publicKey = [publicKey retain];

     }

     return self;

 }

 - (id) initWithKeyRef: (SecKeyRef)privateKey

          publicKeyRef: (SecKeyRef)publicKeyRef

 {

     MYPublicKey *publicKey = [[MYPublicKey alloc] initWithKeyRef: publicKeyRef];

     self = [self _initWithKeyRef: privateKey publicKey: publicKey];

     [publicKey release];

     return self;

 }

 - (id) _initWithKeyRef: (SecKeyRef)privateKey 

          publicKeyData: (NSData*)pubKeyData

            forKeychain: (SecKeychainRef)keychain 

 {

     if (!privateKey) {

         [self release];

         return nil;

     }

     MYPublicKey *pubKey = [[MYPublicKey alloc] _initWithKeyData: pubKeyData forKeychain: keychain];

     if (!pubKey) {

         [self release];

         return nil;

     }

     self = [super initWithKeyRef: privateKey];

     if (self) {

         _publicKey = pubKey;

     } else {

         [pubKey removeFromKeychain];

         [pubKey release];

     }

     return self;

 }

 #if !TARGET_OS_IPHONE

 // The public API for this is in MYKeychain.

 - (id) _initWithKeyData: (NSData*)privKeyData 

           publicKeyData: (NSData*)pubKeyData

             forKeychain: (SecKeychainRef)keychain 

              alertTitle: (NSString*)title

             alertPrompt: (NSString*)prompt

 {

     // Try to import the private key first, since the user might cancel the passphrase alert.

     SecKeyImportExportParameters params = {

         .flags = kSecKeySecurePassphrase,

         .alertTitle = (CFStringRef) title,

         .alertPrompt = (CFStringRef) prompt

     };

     SecKeyRef privateKey = importKey(privKeyData,kSecItemTypePrivateKey,keychain,&params);

     return [self _initWithKeyRef: privateKey publicKeyData: pubKeyData forKeychain: keychain];

 }

 // This method is for testing, so unit-tests don't require user intervention.

 // It's deliberately not made public, to discourage clients from trying to manage the passphrases

 // themselves (this is less secure than letting the Security agent do it.)

 - (id) _initWithKeyData: (NSData*)privKeyData 

           publicKeyData: (NSData*)pubKeyData

             forKeychain: (SecKeychainRef)keychain 

              passphrase: (NSString*)passphrase

 {

     SecKeyImportExportParameters params = {

         .passphrase = (CFStringRef) passphrase,

     };

     SecKeyRef privateKey = importKey(privKeyData,kSecItemTypePrivateKey,keychain,&params);

     return [self _initWithKeyRef: privateKey publicKeyData: pubKeyData forKeychain: keychain];

 }

 - (MYIdentity*) createSelfSignedIdentityWithAttributes: (NSDictionary*)attributes {

     return MYIdentityCreateSelfSigned(self, attributes);

 }

 #endif

 - (void) dealloc

 {

     [_publicKey release];

     [super dealloc];

 }

 + (MYPrivateKey*) _generateRSAKeyPairOfSize: (unsigned)keySize

                                  inKeychain: (MYKeychain*)keychain 

 {

     Assert( keySize == 512 || keySize == 1024 || keySize == 2048, @"Unsupported key size %u", keySize );

     SecKeyRef pubKey=NULL, privKey=NULL;

     OSStatus err;

 #if MYCRYPTO_USE_IPHONE_API

     NSDictionary *pubKeyAttrs = $dict({(id)kSecAttrIsPermanent, $true});

     NSDictionary *privKeyAttrs = $dict({(id)kSecAttrIsPermanent, $true});

     NSDictionary *keyAttrs = $dict( {(id)kSecAttrKeyType, (id)kSecAttrKeyTypeRSA},

                                     {(id)kSecAttrKeySizeInBits, $object(keySize)},

                                     {(id)kSecPublicKeyAttrs, pubKeyAttrs},

                                     {(id)kSecPrivateKeyAttrs, privKeyAttrs} );

     err = SecKeyGeneratePair((CFDictionaryRef)keyAttrs,&pubKey,&privKey);

 #else

     err = SecKeyCreatePair(keychain.keychainRefOrDefault,

                            CSSM_ALGID_RSA, 

                            keySize,

                            0LL,

                            CSSM_KEYUSE_ENCRYPT | CSSM_KEYUSE_VERIFY,        // public key

                            CSSM_KEYATTR_EXTRACTABLE | CSSM_KEYATTR_PERMANENT,

                            CSSM_KEYUSE_DECRYPT | CSSM_KEYUSE_SIGN,          // private key

                            CSSM_KEYATTR_EXTRACTABLE | CSSM_KEYATTR_SENSITIVE | CSSM_KEYATTR_PERMANENT,

                            NULL, // SecAccessRef

                            &pubKey, &privKey);

 #endif

     if (!check(err, @"SecKeyCreatePair")) {

         return nil;

     } else

         return [[[self alloc] initWithKeyRef: privKey publicKeyRef: pubKey] autorelease];

 }

 #pragma mark -

 #pragma mark ACCESSORS:

 - (NSString*) description {

     return $sprintf(@"%@[%@]", [self class], self.publicKeyDigest.abbreviatedHexString);

 }

 @synthesize publicKey=_publicKey;

 - (MYSHA1Digest*) publicKeyDigest {

     return _publicKey.publicKeyDigest;

 }

 - (SecExternalItemType) keyType {

 #if MYCRYPTO_USE_IPHONE_API

     return kSecAttrKeyClassPublic;

 #else

     return kSecItemTypePrivateKey;

 #endif

 }

 - (NSData *) keyData {

     [NSException raise: NSGenericException format: @"Can't access keyData of a PrivateKey"];

     return nil;

 }

 - (BOOL) setValue: (NSString*)valueStr ofAttribute: (SecKeychainAttrType)attr {

     return [super setValue: valueStr ofAttribute: attr]

         && [_publicKey setValue: valueStr ofAttribute: attr];

 }

 #pragma mark -

 #pragma mark OPERATIONS:

 - (BOOL) removeFromKeychain {

     return [super removeFromKeychain]

         && [_publicKey removeFromKeychain];

 }

 - (NSData*) decryptData: (NSData*)data {

     return [self _crypt: data operation: NO];

 }

 - (NSData*) signData: (NSData*)data {

     Assert(data);

 #if MYCRYPTO_USE_IPHONE_API

     uint8_t digest[CC_SHA1_DIGEST_LENGTH];

     CC_SHA1(data.bytes,data.length, digest);

     size_t sigLen = 1024;

     uint8_t sigBuf[sigLen];

     OSStatus err = SecKeyRawSign(self.keyRef, kSecPaddingPKCS1SHA1,

                                  digest,sizeof(digest), //data.bytes, data.length,

                                  sigBuf, &sigLen);

     if(err) {

         Warn(@"SecKeyRawSign failed: %i",err);

         return nil;

     } else

         return [NSData dataWithBytes: sigBuf length: sigLen];

 #else

     NSData *signature = nil;

     CSSM_CC_HANDLE ccHandle = [self _createSignatureContext: CSSM_ALGID_SHA256WithRSA];

     if (!ccHandle) return nil;

     CSSM_DATA original = {data.length, (void*)data.bytes};

     CSSM_DATA result = {0,NULL};

     if (checkcssm(CSSM_SignData(ccHandle, &original, 1, CSSM_ALGID_NONE, &result), @"CSSM_SignData"))

         signature = [NSData dataWithBytesNoCopy: result.Data length: result.Length

                                    freeWhenDone: YES];

     CSSM_DeleteContext(ccHandle);

     return signature;

 #endif

 }

 #if !TARGET_OS_IPHONE

 - (NSData*) exportKeyInFormat: (SecExternalFormat)format 

                       withPEM: (BOOL)withPEM

                    alertTitle: (NSString*)title

                   alertPrompt: (NSString*)prompt

 {

     SecKeyImportExportParameters params = {

         .version = SEC_KEY_IMPORT_EXPORT_PARAMS_VERSION,

         .flags = kSecKeySecurePassphrase,

         .alertTitle = (CFStringRef)title,

         .alertPrompt = (CFStringRef)prompt

     };

     CFDataRef data = NULL;

     if (check(SecKeychainItemExport(self.keyRef,

                                     format, (withPEM ?kSecItemPemArmour :0), 

                                     &params, &data),

               @"SecKeychainItemExport"))

         return [(id)CFMakeCollectable(data) autorelease];

     else

         return nil;

 }

 - (NSData*) exportKey {

     return [self exportKeyInFormat: kSecFormatWrappedOpenSSL withPEM: YES

                         alertTitle: @"Export Private Key"

                        alertPrompt: @"Enter a passphrase to protect the private-key file.\n"

             "You will need to re-enter the passphrase later when importing the key from this file, "

             "so keep it in a safe place."];

     //FIX: Should make these messages localizable.

 }

 - (NSData*) _exportKeyInFormat: (SecExternalFormat)format

                        withPEM: (BOOL)withPEM

                     passphrase: (NSString*)passphrase

 {

     SecKeyImportExportParameters params = {

         .version = SEC_KEY_IMPORT_EXPORT_PARAMS_VERSION,

         .passphrase = (CFStringRef)passphrase

     };

     CFDataRef data = NULL;

     if (check(SecKeychainItemExport(self.keyRef,

                                     format, (withPEM ?kSecItemPemArmour :0), 

                                     &params, &data),

               @"SecKeychainItemExport"))

         return [(id)CFMakeCollectable(data) autorelease];

     else

         return nil;

 }

 #endif TARGET_OS_IPHONE

 @end