public static string Encode(byte[] plaintext)
{
ContractsCommon.NotNull(plaintext, "plaintext");
ContractsCommon.ResultIsNonNull <string>();
var plaintextArr = new byte[plaintext.Length + 1];
Array.Copy(plaintext, 0, plaintextArr, 1, plaintext.Length);
Array.Reverse(plaintextArr);
var workingValue = new BigInteger(plaintextArr);
StringBuilder sb = new StringBuilder(plaintext.Length * 138 / 100 + 1);
while (workingValue.CompareTo(BigInteger.Zero) > 0)
{
BigInteger remainder;
workingValue = BigInteger.DivRem(workingValue, Base, out remainder);
sb.Append(Alphabet[(int)remainder]);
}
Contract.Assert(workingValue.Sign >= 0);
//sb.Insert(0, Alphabet[(int)workingValue]);
for (int i = 0; i < plaintext.Length && plaintext[i] == 0; ++i)
{
sb.Append(Alphabet[0]);
}
var retVal = new char[sb.Length];
sb.CopyTo(0, retVal, 0, sb.Length);
Array.Reverse(retVal);
return(new string(retVal));
}
public static string EncodeWithCheck(byte[] plaintext)
{
ContractsCommon.NotNull(plaintext, "plaintext");
ContractsCommon.ResultIsNonNull <string>();
return(EncodeWithCheck(new byte[0], plaintext));
}
public static byte[] ToBytesArrayBE(this BigInteger bi)
{
ContractsCommon.ResultIsNonNull <byte[]>();
Contract.Ensures(Contract.Result <byte[]>().Length == bi.ToByteArray().Length);
var resultArray = bi.ToByteArray();
Array.Reverse(resultArray);
return(resultArray);
}
public static string EncodeWithCheck(byte[] prefix, byte[] plaintext)
{
ContractsCommon.NotNull(prefix, "prefix");
ContractsCommon.NotNull(plaintext, "plaintext");
ContractsCommon.ResultIsNonNull <string>();
var plaintextArr = (byte[])plaintext.Clone();
var hash = Cryptography.CryptoFunctionProviderFactory.Default.Hash256(plaintextArr, prefix);
var plaintextExtended = new byte[plaintext.Length + prefix.Length + 4];
Array.Copy(plaintext, 0, plaintextExtended, 0, plaintext.Length);
Array.Copy(prefix, 0, plaintextExtended, plaintext.Length, prefix.Length);
Array.Copy(hash.Bytes, 0, plaintextExtended, prefix.Length + plaintext.Length, 4);
return(Encode(plaintextExtended));
}
public static byte[] Decode(string enc)
{
ContractsCommon.NotNull(enc, "enc");
Contract.Requires <FormatException>(Contract.ForAll(0, enc.Length, i => Alphabet.IndexOf(enc[i]) != -1));
ContractsCommon.ResultIsNonNull <byte[]>();
if (enc.Length == 0)
{
return(new byte[0]);
}
var workingValue = BigInteger.Zero;
for (int i = 0; i < enc.Length; ++i)
{
var index = new BigInteger(Alphabet.IndexOf(enc[i]));
workingValue = workingValue + index * BigInteger.Pow(Base, enc.Length - 1 - i);
}
var retVal = workingValue.ToByteArray();
Array.Reverse(retVal);
if (retVal[0] == 0 && workingValue > 0)
{
var newBytes = new byte[retVal.Length - 1];
Array.Copy(retVal, 1, newBytes, 0, newBytes.Length);
retVal = newBytes;
}
var count = 0;
while (enc[count] == Alphabet[0])
{
++count;
}
if (count > 0)
{
var newBytes = new byte[retVal.Length + count];
Array.Copy(retVal, 0, newBytes, count, retVal.Length);
retVal = newBytes;
}
return(retVal);
}
