我试图从Swift调用CCKeyDerivationPBKDF。
我已在Project-Bridging-Header.h中导入了必需的标题：
#import <CommonCrypto/CommonKeyDerivation.h>
（顺便说一下，桥接标题似乎可以正常导入我的项目中的其他Objective C代码。）
在Xcode中，我可以从我的.swift文件跳转到这里显示的定义：
int
CCKeyDerivationPBKDF( CCPBKDFAlgorithm algorithm, const char *password, size_t passwordLen,
const uint8_t *salt, size_t saltLen,
CCPseudoRandomAlgorithm prf, uint rounds,
uint8_t *derivedKey, size_t derivedKeyLen)
最后，当我尝试这样调用函数时：
let result = CCKeyDerivationPBKDF(CCPBKDFAlgorithm(kCCPBKDF2), NSString(password).UTF8String, size_t(passwordLength), UnsafePointer<UInt8>(salt.bytes), size_t(salt.length), CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256), uint(actualRoundCount), UnsafeMutablePointer<UInt8>(derivedKey.mutableBytes), size_t(derivedKey.length));
...我得到了这个编译错误：
无法调用＆＃39; init＆＃39;使用类型＆＃39;的参数列表（CCPBKDFAlgorithm， UnsafePointer，size_t，UnsafePointer，size_t， CCPseudoRandomAlgorithm，uint，UnsafeMutablePointer，size_t）＆＃39;
我相信所有演员都是正确的（实际上编译器错误帮助我识别每个参数的每个问题） - 这让我觉得编译器理解我调用CCKeyDerivationPBKDF的意图。
但是，在所有其他转换错误消失后，编译器感到困惑，并认为我正在尝试使用初始化程序构建一个类。
希望有人能告诉我我的方式错误。
（Xcode 6 beta 7）
根据要求，上下文中的完整代码：
class func generateAesKeyForPassword(password: String, salt: NSData, roundCount: UInt?, error: NSErrorPointer) -> (key: NSData, actualRoundCount: UInt)?
{
let derivedKey = NSMutableData(length: kCCKeySizeAES256)
let passwordLength = size_t(password.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
var actualRoundCount: UInt
if roundCount != nil
{
actualRoundCount = roundCount!
}
else
{
actualRoundCount = UInt(CCCalibratePBKDF(CCPBKDFAlgorithm(kCCPBKDF2), passwordLength, UInt(salt.length), CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256), UInt(derivedKey.length), UInt32(300) /* milliseconds */));
}
let result = CCKeyDerivationPBKDF(CCPBKDFAlgorithm(kCCPBKDF2), NSString(password).UTF8String, size_t(passwordLength), UnsafePointer<UInt8>(salt.bytes), size_t(salt.length), CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256), uint(actualRoundCount), UnsafeMutablePointer<UInt8>(derivedKey.mutableBytes), size_t(derivedKey.length));
if result != 0
{
let errorDescription = "CCKeyDerivationPBKDF failed with error: '\(result)'"
error.memory = MyError(domain: ClientErrorType.errorDomain, code: Int(result), descriptionText: errorDescription)
return nil
}
return (NSData(data: derivedKey), actualRoundCount)
}
答案 0 :(得分：14)
基于密码的密钥派生既可用于从密码文本中导出加密密钥，也可用于保存密码以进行身份验证。
可以使用几种哈希算法，包括SHA1，SHA256，SHA512，这些算法由此示例代码提供。
rounds参数用于使计算变慢，以便攻击者必须在每次尝试上花费大量时间。典型的延迟值在100ms到500ms之间，如果有不可接受的性能，可以使用更短的值。
此示例需要Common Crypto
项目必须有一个桥接标题：
#import <CommonCrypto/CommonCrypto.h>
将Security.framework添加到项目中。
参数：
password password String
salt salt Data
keyByteCount number of key bytes to generate
rounds Iteration rounds
returns Derived key
func pbkdf2SHA1(password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
return pbkdf2(hash:CCPBKDFAlgorithm(kCCPRFHmacAlgSHA1), password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
}
func pbkdf2SHA256(password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
return pbkdf2(hash:CCPBKDFAlgorithm(kCCPRFHmacAlgSHA256), password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
}
func pbkdf2SHA512(password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
return pbkdf2(hash:CCPBKDFAlgorithm(kCCPRFHmacAlgSHA512), password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
}
func pbkdf2(hash :CCPBKDFAlgorithm, password: String, salt: Data, keyByteCount: Int, rounds: Int) -> Data? {
let passwordData = password.data(using:String.Encoding.utf8)!
var derivedKeyData = Data(repeating:0, count:keyByteCount)
let derivationStatus = derivedKeyData.withUnsafeMutableBytes {derivedKeyBytes in
salt.withUnsafeBytes { saltBytes in
CCKeyDerivationPBKDF(
CCPBKDFAlgorithm(kCCPBKDF2),
password, passwordData.count,
saltBytes, salt.count,
hash,
UInt32(rounds),
derivedKeyBytes, derivedKeyData.count)
}
}
if (derivationStatus != 0) {
print("Error: \(derivationStatus)")
return nil;
}
return derivedKeyData
}
使用示例：
let password = "password"
//let salt = "saltData".data(using: String.Encoding.utf8)!
let salt = Data(bytes: [0x73, 0x61, 0x6c, 0x74, 0x44, 0x61, 0x74, 0x61])
let keyByteCount = 16
let rounds = 100000
let derivedKey = pbkdf2SHA1(password:password, salt:salt, keyByteCount:keyByteCount, rounds:rounds)
print("derivedKey (SHA1): \(derivedKey! as NSData)")
示例输出：
derivedKey (SHA1): <6b9d4fa3 0385d128 f6d196ee 3f1d6dbf>
参数类型和类到实例测试方法的微小更改。
func generateAesKeyForPassword(password: String, salt: NSData, roundCount: Int?, error: NSErrorPointer) -> (key: NSData, actualRoundCount: UInt32)?
{
let nsDerivedKey = NSMutableData(length: kCCKeySizeAES256)
var actualRoundCount: UInt32
// Create Swift intermediates for clarity in function calls
let algorithm: CCPBKDFAlgorithm = CCPBKDFAlgorithm(kCCPBKDF2)
let prf: CCPseudoRandomAlgorithm = CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256)
let saltBytes = UnsafePointer<UInt8>(salt.bytes)
let saltLength = size_t(salt.length)
let nsPassword = password as NSString
let nsPasswordPointer = UnsafePointer<Int8>(nsPassword.cStringUsingEncoding(NSUTF8StringEncoding))
let nsPasswordLength = size_t(nsPassword.lengthOfBytesUsingEncoding(NSUTF8StringEncoding))
var nsDerivedKeyPointer = UnsafeMutablePointer<UInt8>(nsDerivedKey.mutableBytes)
let nsDerivedKeyLength = size_t(nsDerivedKey.length)
let msec: UInt32 = 300
if roundCount != nil {
actualRoundCount = UInt32(roundCount!)
}
else {
actualRoundCount = CCCalibratePBKDF(
algorithm,
nsPasswordLength,
saltLength,
prf,
nsDerivedKeyLength,
msec);
}
let result = CCKeyDerivationPBKDF(
algorithm,
nsPasswordPointer, nsPasswordLength,
saltBytes, saltLength,
prf, actualRoundCount,
nsDerivedKeyPointer, nsDerivedKeyLength)
if result != 0 {
let errorDescription = "CCKeyDerivationPBKDF failed with error: '\(result)'"
// error.memory = MyError(domain: ClientErrorType.errorDomain, code: Int(result), descriptionText: errorDescription)
return nil
}
return (nsDerivedKey, actualRoundCount)
}
//添加奖金：
func salt(#length:UInt) -> NSData {
let salt = NSMutableData(length: Int(length))
var saltPointer = UnsafeMutablePointer<UInt8>(salt.mutableBytes)
SecRandomCopyBytes(kSecRandomDefault, length, saltPointer);
return salt
}
//测试电话：
let password = "test pass"
let salt = self.salt(length:32)
let roundCount = 300
var error: NSError?
let result = self.generateAesKeyForPassword(password, salt:salt, roundCount:roundCount, error:&error)
println("result: \(result)")
输出：
result: Optional((<d279ab8d 8ace67b7 abec844c b9979d20 f2bb0a7f 5af70502 085bf1e4 1016b20c>, 300))
答案 1 :(得分：1)
所以我相信这有效：
let result = CCKeyDerivationPBKDF(CCPBKDFAlgorithm(kCCPBKDF2), NSString(string: password).UTF8String, size_t(passwordLength), UnsafePointer<UInt8>(salt.bytes), size_t(salt.length), CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA256), uint(actualRoundCount), UnsafeMutablePointer<UInt8>(derivedKey.mutableBytes), size_t(derivedKey.length));
在Swift 1.2+中，不再需要size_t强制转换：
let result = CCKeyDerivationPBKDF(CCPBKDFAlgorithm(kCCPBKDF2), NSString(string: password).UTF8String, passwordLength, UnsafePointer<UInt8>(salt.bytes), salt.length, CCPseudoRandomAlgorithm(kCCPRFHmacAlgSHA512), uint(actualRoundCount), UnsafeMutablePointer<UInt8>(derivedKey.mutableBytes), derivedKey.length)
请注意，这是错误的：
NSString(password).UTF8String
应该是：
NSString(string: password).UTF8String
编译器错误肯定会误导（仍为测试版）