bigdata error

[simphonydeveloper]

Error: The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.

var keyList = RsaKeyGenerator.Pkcs1Key(2048, false);
......

var bigDataRsa = new RsaPkcs1Util(Encoding.UTF8, PUBLIC_KEY, PRIVATE_LEY, 2048);
var text=bigDataRsa.EncryptBigData("12312312312", RSAEncryptionPadding.Pkcs1);
......
var bigDataRsa = new RsaPkcs1Util(Encoding.UTF8, PUBLIC_KEY, PRIVATE_LEY, 2048);
var result= string.Join("", bigDataRsa.DecryptBigData(data, RSAEncryptionPadding.Pkcs1));
......
  public const string PUBLIC_KEY = "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA85hHtD6EsFDETuyWcNd/TPBh5ljTO831aagxC0eKSVokCJlh5Y0CIdXd7iI4pRnCO9sej2ZL4p3wKgQqRF0dAWu8wUuxcXyqlNsdSAl25JLHaRpaE/hwDO3weSiLPao8eTjqepV2q0eJX6nJ5QU6L5E9W7vUDMQ1nlEVbclKJl3SSNTuFGVqyk8RtjG35vJkmeV1P5TL3yOMxbGmJnEqfR/dVo/ikv7sTYWvVLOzPStkTYroYPZnLKjV6r55UuKDgxVPKx5MoJB7EzSIkKqbfic1f5vscNFASWo2tW2adUvUA89wWs2YRzY5bZHmA9Ufdl8tRxAK+gb5YYGSTYkTdwIDAQAB";
public const string PRIVATE_LEY = "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";

my encryption result

HawPwqw9AKffjb1hedGoDT71JB0hfxgCCj35h+XMkoPpAjtn7Bdl3i0QOv7lulAoFa1cp6x8Jf5WhbvRsrDyDGW5Gile3Uwdzkj0Nhdyo6Fdh4Vxh8dgkLle6UIoixA3wvgNQME2tvZNhwBT7r9ZIZkdUP10kKnljTSU+lxeCFZ+XbTQZ7tbLXL6oNajCe/ecOT7/gve/+qtDYvn1TUVf8fN2RehtqfEwSwKdXaEqicFfQJOBt3iKjOrAsUeKu2fL3lkppkMNCM+3oB7h64Yx51UwOe6+l0s3EQ5HDw/nP04ZmES6W2Srg0JOY2NJy8k5UvzxxuaCp8V3bKOnYKIbg==

why i must input privatekey when decrypt. in fact , your code privatekey default value is null.
thank you.