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qiubaiying · qiubaiying · commit 1af2e0545c05 · 2017-07-19T16:07:26.000+08:00
Signed-off-by: BY &lt;qiubaiying@gmail.com&gt;
diff --git a/_posts/2017-07-19-Swift的HMAC和SHA1加密.md b/_posts/2017-07-19-Swift的HMAC和SHA1加密.md
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+---
+layout:     post
+title:      Swift的HMAC和SHA1加密
+subtitle:   swift中利用HMAC的SHA1对文本进行加密
+date:       2017-07-04
+author:     BY
+header-img: img/post-bg-coffee.jpeg
+catalog: true
+tags:
+    - Swift
+---
+
+>HMAC是密钥相关的哈希运算消息认证码（Hash-based Message Authentication Code）。 HMAC运算利用哈希算法，以一个密钥和一个消息为输入，生成一个消息摘要作为输出。也就是说HMAC通过将哈希算法(SHA1, MD5)与密钥进行计算生成摘要。
+
+## Objectice-C
+
+在上个 Objectice-C 项目中，使用的 HMAC 和 SHA1 进行加密。如下代码：
+
+```objc
++ (NSString *)hmacsha1:(NSString *)text key:(NSString *)secret {
+    
+    NSData *secretData = [secret dataUsingEncoding:NSUTF8StringEncoding];
+    NSData *clearTextData = [text dataUsingEncoding:NSUTF8StringEncoding];
+    unsigned char result[20];
+    // SHA1加密
+    CCHmac(kCCHmacAlgSHA1, [secretData bytes], [secretData length], [clearTextData bytes], [clearTextData length], result);
+    char base64Result[32];
+    size_t theResultLength = 32;
+    // 转为Base64
+    Base64EncodeData(result, 20, base64Result, &theResultLength,YES);
+    NSData *theData = [NSData dataWithBytes:base64Result length:theResultLength];
+    NSString *base64EncodedResult = [[NSString alloc] initWithData:theData encoding:NSUTF8StringEncoding];
+    return base64EncodedResult;
+}
+```
+
+
+
+## swift
+
+最近用 swift 重构项目,用 Swift [重写了](https://stackoverflow.com/questions/26970807/implementing-hmac-and-sha1-encryption-in-swift?rq=1) HMAC 的 SHA1 加密方式。
+
+### 使用
+
+```swift
+// 使用HMAC和SHA加密
+let hmacResult:String = "myStringToHMAC".hmac(HMACAlgorithm.SHA1, key: "myKey")
+```
+
+### 代码
+
+使用下面代码时，需要在 OC 桥接文件`xxx-Bridging-Header`中 `#import <CommonCrypto/CommonHMAC.h>`
+
+```swift
+extension String {
+    func hmac(algorithm: HMACAlgorithm, key: String) -> String {
+        let cKey = key.cStringUsingEncoding(NSUTF8StringEncoding)
+        let cData = self.cStringUsingEncoding(NSUTF8StringEncoding)
+        var result = [CUnsignedChar](count: Int(algorithm.digestLength()), repeatedValue: 0)
+        CCHmac(algorithm.toCCHmacAlgorithm(), cKey!, strlen(cKey!), cData!, strlen(cData!), &result)
+        var hmacData:NSData = NSData(bytes: result, length: (Int(algorithm.digestLength())))
+        var hmacBase64 = hmacData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding76CharacterLineLength)
+        return String(hmacBase64)
+    }
+}
+
+enum HMACAlgorithm {
+    case MD5, SHA1, SHA224, SHA256, SHA384, SHA512
+
+    func toCCHmacAlgorithm() -> CCHmacAlgorithm {
+        var result: Int = 0
+        switch self {
+        case .MD5:
+            result = kCCHmacAlgMD5
+        case .SHA1:
+            result = kCCHmacAlgSHA1
+        case .SHA224:
+            result = kCCHmacAlgSHA224
+        case .SHA256:
+            result = kCCHmacAlgSHA256
+        case .SHA384:
+            result = kCCHmacAlgSHA384
+        case .SHA512:
+            result = kCCHmacAlgSHA512
+        }
+        return CCHmacAlgorithm(result)
+    }
+
+    func digestLength() -> Int {
+        var result: CInt = 0
+        switch self {
+        case .MD5:
+            result = CC_MD5_DIGEST_LENGTH
+        case .SHA1:
+            result = CC_SHA1_DIGEST_LENGTH
+        case .SHA224:
+            result = CC_SHA224_DIGEST_LENGTH
+        case .SHA256:
+            result = CC_SHA256_DIGEST_LENGTH
+        case .SHA384:
+            result = CC_SHA384_DIGEST_LENGTH
+        case .SHA512:
+            result = CC_SHA512_DIGEST_LENGTH
+        }
+        return Int(result)
+    }
+}
+
+
+```
+
