Swift Language Cryptographic Hashing HMAC with MD5, SHA1, SHA224, SHA256, SHA384, SHA512 (Swift 3)

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Example

These functions will hash either String or Data input with one of eight cryptographic hash algorithms.

The name parameter specifies the hash function name as a String Supported functions are MD5, SHA1, SHA224, SHA256, SHA384 and SHA512

This example requires Common Crypto
It is necessary to have a bridging header to the project:
#import <CommonCrypto/CommonCrypto.h>
Add the Security.framework to the project.

These functions takes a hash name, message to be hashed, a key and return a digest:


hashName: name of a hash function as String  
message:  message as Data  
key:      key as Data  
returns:  digest as Data  
func hmac(hashName:String, message:Data, key:Data) -> Data? {
    let algos = ["SHA1":   (kCCHmacAlgSHA1,   CC_SHA1_DIGEST_LENGTH),
                 "MD5":    (kCCHmacAlgMD5,    CC_MD5_DIGEST_LENGTH),
                 "SHA224": (kCCHmacAlgSHA224, CC_SHA224_DIGEST_LENGTH),
                 "SHA256": (kCCHmacAlgSHA256, CC_SHA256_DIGEST_LENGTH),
                 "SHA384": (kCCHmacAlgSHA384, CC_SHA384_DIGEST_LENGTH),
                 "SHA512": (kCCHmacAlgSHA512, CC_SHA512_DIGEST_LENGTH)]
    guard let (hashAlgorithm, length) = algos[hashName]  else { return nil }
    var macData = Data(count: Int(length))

    macData.withUnsafeMutableBytes {macBytes in
        message.withUnsafeBytes {messageBytes in
            key.withUnsafeBytes {keyBytes in
                CCHmac(CCHmacAlgorithm(hashAlgorithm),
                       keyBytes,     key.count,
                       messageBytes, message.count,
                       macBytes)
            }
        }
    }
    return macData
}

hashName: name of a hash function as String
message:  message as String
key:      key as String
returns:  digest as Data
func hmac(hashName:String, message:String, key:String) -> Data? {
    let messageData = message.data(using:.utf8)!
    let keyData = key.data(using:.utf8)!
    return hmac(hashName:hashName, message:messageData, key:keyData)
}

hashName: name of a hash function as String  
message:  message as String  
key:      key as Data  
returns:  digest as Data  
func hmac(hashName:String, message:String, key:Data) -> Data? {
    let messageData = message.data(using:.utf8)!
    return hmac(hashName:hashName, message:messageData, key:key)
}

// Examples

let clearString = "clearData0123456"
let keyString   = "keyData8901234562"
let clearData   = clearString.data(using:.utf8)!
let keyData     = keyString.data(using:.utf8)!
print("clearString: \(clearString)")
print("keyString:   \(keyString)")
print("clearData: \(clearData as NSData)")
print("keyData:   \(keyData as NSData)")

let hmacData1 = hmac(hashName:"SHA1", message:clearData, key:keyData)
print("hmacData1: \(hmacData1! as NSData)")

let hmacData2 = hmac(hashName:"SHA1", message:clearString, key:keyString)
print("hmacData2: \(hmacData2! as NSData)")

let hmacData3 = hmac(hashName:"SHA1", message:clearString, key:keyData)
print("hmacData3: \(hmacData3! as NSData)")

Output:

clearString: clearData0123456
keyString:   keyData8901234562
clearData: <636c6561 72446174 61303132 33343536>
keyData:   <6b657944 61746138 39303132 33343536 32>

hmacData1: <bb358f41 79b68c08 8e93191a da7dabbc 138f2ae6>
hmacData2: <bb358f41 79b68c08 8e93191a da7dabbc 138f2ae6>
hmacData3: <bb358f41 79b68c08 8e93191a da7dabbc 138f2ae6>


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