MD5 with CommonCrypto in Swift 3.0

MD5.swift

// requires a bridging header with this:
// #import <CommonCrypto/CommonCrypto.h>

func MD5(_ string: String) -> String? {
    let length = Int(CC_MD5_DIGEST_LENGTH)
    var digest = [UInt8](repeating: 0, count: length)
    if let d = string.data(using: String.Encoding.utf8) {
        d.withUnsafeBytes { (body: UnsafePointer<UInt8>) in
            CC_MD5(body, CC_LONG(d.count), &digest)
        }
    }
    return (0..<length).reduce("") {
        $0 + String(format: "%02x", digest[$1])
    }
}

There is a warning: Result of call to 'withUnsafeBytes' is unused

Maybe a simpler version, without the warning:

func md5(string: String) -> String {
    let length = Int(CC_MD5_DIGEST_LENGTH)
    var digest = [UInt8](repeating: 0, count: length)
    var data = string.utf8
    CC_MD5(&data, CC_LONG(data.count), &digest)
    return digest.map { String(format: "%02x", $0) }.joined()
}

Use "%02X" for uppercase.

Update for Swift 5?

The last one from April 5th, works with Swift 5 also

I'm seeing this