Swift String SHA256

String+SHA256.swift

extentsion String {
  
  func SHA256() -> String {
        if let stringData = self.data(using: .utf8) {
            return self.hexStringFromData(input: digest(input: stringData as NSData))
        } else {
            return self
        }
    }

    private func digest(input: NSData) -> NSData {
        let digestLength = Int(CC_SHA256_DIGEST_LENGTH)
        var hash = [UInt8](repeating: 0, count: digestLength)
        CC_SHA256(input.bytes, UInt32(input.length), &hash)
        return NSData(bytes: hash, length: digestLength)
    }

    private  func hexStringFromData(input: NSData) -> String {
        var bytes = [UInt8](repeating: 0, count: input.length)
        input.getBytes(&bytes, length: input.length)

        var hexString = ""
        for byte in bytes {
            hexString += String(format: "%02x", UInt8(byte))
        }

        return hexString
    }
  
}