SHA256 in Swift - Importing framework issue

Question

I'm trying to use CC_SHA256_DIGEST_LENGTH in one of my functions in Swift and it throws an error because it cannot find that symbol. I've tried everything, importing CommonCrypto in the bridge-header and trying that .map solution.. Nothing works.

How can I use CC_SHA256_DIGEST_LENGTH in Swift? All the solutions seems to have stopped working. Thank you!

Answer 1

Add the following line to your bridging header:
#import <CommonCrypto/CommonHMAC.h>

Swift 2.x example:

func doSha256(#dataIn:NSData) -> NSData {
    var shaOut: NSMutableData! = NSMutableData(length: Int(CC_SHA256_DIGEST_LENGTH));
    CC_SHA256(dataIn.bytes, CC_LONG(dataIn.length), UnsafeMutablePointer<UInt8>(shaOut.mutableBytes));

    return shaOut;
}

Swift 3.0 example:

func hashSHA256(data:Data) -> Data? {
    var hashData = Data(count: Int(CC_SHA256_DIGEST_LENGTH))
    _ = hashData.withUnsafeMutableBytes {digestBytes in
        data.withUnsafeBytes {messageBytes in
            CC_SHA256(messageBytes, CC_LONG(data.count), digestBytes)
        }
    }
    return hashData
}

let clearData   = "clearData0123456".data(using:String.Encoding.utf8)!
print("clearData: \(clearData.map { String(format: "%02hhx", $0) }.joined())")

let hash = hashSHA256(data:clearData)
print("hash: \(hash!.map { String(format: "%02hhx", $0) }.joined())")

Output:

clearData: 636c6561724461746130313233343536
hash: aabc766b6b357564e41f4f912d494bccbfa16924b574abbdba9e3e9da0c8920a

I don't have any frameworks added in the target Build Phases.
Be are you sure that the bridging-header is set up correctly? I added mine by adding a .m file and let the system automatically add the bridging-header and update any target settings.

General hash method moved from the sunsetted documentation section:

This function takes a hash name and Data to be hashed and returns a Data:

name: A name of a hash function as a String  
data: The Data to be hashed  
returns: the hashed result as Data  

func hash(name:String, data:Data) -> Data? {
    let algos = ["MD2":    (CC_MD2,    CC_MD2_DIGEST_LENGTH),
                 "MD4":    (CC_MD4,    CC_MD4_DIGEST_LENGTH),
                 "MD5":    (CC_MD5,    CC_MD5_DIGEST_LENGTH),
                 "SHA1":   (CC_SHA1,   CC_SHA1_DIGEST_LENGTH),
                 "SHA224": (CC_SHA224, CC_SHA224_DIGEST_LENGTH),
                 "SHA256": (CC_SHA256, CC_SHA256_DIGEST_LENGTH),
                 "SHA384": (CC_SHA384, CC_SHA384_DIGEST_LENGTH),
                 "SHA512": (CC_SHA512, CC_SHA512_DIGEST_LENGTH)]
    guard let (hashAlgorithm, length) = algos[name]  else { return nil }
    var hashData = Data(count: Int(length))

    _ = hashData.withUnsafeMutableBytes {digestBytes in
        data.withUnsafeBytes {messageBytes in
            hashAlgorithm(messageBytes, CC_LONG(data.count), digestBytes)
        }
    }
    return hashData
}

Note: MD2, MD4, MD5 and SHA1 should not be used in new work, they are no longer secure for message digest usage.