title: Chilkat iOS10+ RSA compatibility issue
body: <p>I'm using native RSA in one iOS app and Chilkat RSA library in another. On a native iOS side I encrypt (OAEP SHA256) data with the following function:</p>
  
  <pre><code>    static func encryptWithKey(_ data: Data, rsaKey: SecKey) -&gt; Data? {
          let algorithm = SecKeyAlgorithm.rsaEncryptionOAEPSHA256
  
          guard SecKeyIsAlgorithmSupported(rsaKey, .encrypt, algorithm) else { return nil }
  
          var error: Unmanaged&lt;CFError&gt;?
          let encryptedData = SecKeyCreateEncryptedData(rsaKey, algorithm, data as CFData, &amp;error)
  
          if let encryptionError = error {
              print(encryptionError.takeRetainedValue())
          }
  
          return encryptedData as Data?
      }
  </code></pre>
  
  <p>and then in another app, I decrypt this data with Chilkat library:</p>
  
  <pre><code>static func decrypt(base64 encryptedText: String, with xmlKey: String) -&gt; Data? {
      let privateKey = CkoPrivateKey()
  
      guard let success = privateKey?.loadXml(xmlKey), success else { return nil }
      guard let rsa = CkoRsa() else { return nil }
  
      rsa.unlockComponent(Chilkat.key)
  
      rsa.oaepPadding  = true
      rsa.littleEndian = false
      rsa.oaepHash     = "sha256"
      rsa.encodingMode = "base64"
  
      rsa.importPrivateKeyObj(privateKey)
  
      if let decryptedData = rsa.decryptBytesENC(encryptedText, bUsePrivateKey: true) {
          return decryptedData
      } else {
          print(rsa.lastErrorText)
      }
  
      return nil
  }
  </code></pre>
  
  <p>Even I used one private / public keys pair I'm getting an error (from rsa.lastErrorText):</p>
  
  <pre><code>"ChilkatLog:
  DecryptBytesENC(7ms):
      DllDate: Feb  1 2018
      ChilkatVersion: 9.5.0.72
      UnlockPrefix: XXXXXXXXXXXX
      Architecture: Little Endian; 64-bit
      Language: IOS C/C++/Swift/Objective-C
      VerboseLogging: 1
      usePrivateKey: 1
      Component successfully unlocked using purchased unlock code.
      rsaDecryptBytes(7ms):
      rsa_decrypt(7ms):
      KeyType: Private
      InputSize: 256
      Padding: OAEP
      OaepHashAlg: SHA-256
      MgfHashAlg: SHA-1
      ParamLen: 0
      ModulusBitLen: 2048
      inlen: 256
      modulus_bytelen: 256
      modulus_bitlen: 2048
      bigEndian: 0
      Byte swapping from big-endian to little-endian
      padding: OAEP
      No leading zero byte for OAEP decoding.
      OAEP decoding failed.
      --rsa_decrypt
      --rsaDecryptBytes
      Failed.
      --DecryptBytesENC
      --ChilkatLog"
  </code></pre>
  
  <p>Any ideas?</p>