如何在iOS中使用ECC

在iOS中有使用ECC的例子吗？

我注意到在Apple Developer Documents中的kSecAttrKeyTypeEC，但我不能用它来通用密钥对。

下面的代码是从示例CryptoExercise中修改的

// Container dictionaries. NSMutableDictionary * privateKeyAttr = [[NSMutableDictionary alloc] init]; NSMutableDictionary * publicKeyAttr = [[NSMutableDictionary alloc] init]; NSMutableDictionary * keyPairAttr = [[NSMutableDictionary alloc] init]; // Set top level dictionary for the keypair. [keyPairAttr setObject:(id)kSecAttrKeyTypeEC forKey:(id)kSecAttrKeyType]; [keyPairAttr setObject:[NSNumber numberWithUnsignedInteger:keySize] forKey:(id)kSecAttrKeySizeInBits]; // Set the private key dictionary. [privateKeyAttr setObject:[NSNumber numberWithBool:YES] forKey:(id)kSecAttrIsPermanent]; [privateKeyAttr setObject:privateTag forKey:(id)kSecAttrApplicationTag]; // See SecKey.h to set other flag values. // Set the public key dictionary. [publicKeyAttr setObject:[NSNumber numberWithBool:YES] forKey:(id)kSecAttrIsPermanent]; [publicKeyAttr setObject:publicTag forKey:(id)kSecAttrApplicationTag]; // See SecKey.h to set other flag values. // Set attributes to top level dictionary. [keyPairAttr setObject:privateKeyAttr forKey:(id)kSecPrivateKeyAttrs]; [keyPairAttr setObject:publicKeyAttr forKey:(id)kSecPublicKeyAttrs]; // SecKeyGeneratePair returns the SecKeyRefs just for educational purposes. sanityCheck = SecKeyGeneratePair((CFDictionaryRef)keyPairAttr, &publicKeyRef, &privateKeyRef); LOGGING_FACILITY( sanityCheck == noErr && publicKeyRef != NULL && privateKeyRef != NULL, @"Something really bad went wrong with generating the key pair." ); 

sanityCheck总是返回-50这意味着'errSecParam'。

我真的不知道如何使用它，谢谢你阅读这个。

Answer 1

 NSDictionary *parameters = @{ (__bridge id)kSecAttrKeyType: (__bridge id)kSecAttrKeyTypeEC, (__bridge id)kSecAttrKeySizeInBits: @256, (__bridge id)kSecPrivateKeyAttrs: @{ (__bridge id)kSecAttrIsPermanent: @YES, (__bridge id)kSecAttrApplicationTag: [@"my.key.tag" dataUsingEncoding:NSUTF8StringEncoding], }, (__bridge id)kSecPublicKeyAttrs: @{ (__bridge id)kSecAttrIsPermanent: @YES, (__bridge id)kSecAttrApplicationTag: [@"my.key.pubtag" dataUsingEncoding:NSUTF8StringEncoding], } }; SecKeyRef publicKey, privateKey; OSStatus status = SecKeyGeneratePair((__bridge CFDictionaryRef)parameters, &publicKey, &privateKey); 

这个工程，仔细检查您的密钥大小参数。

请注意，目前EC密钥只能用于签署/validation数据。 encryption/解密返回errSecUnimplemented = -4.