using Org.BouncyCastle.Crypto.Parameters; using Org.BouncyCastle.Utilities; using System; namespace Org.BouncyCastle.Crypto.Fpe { public abstract class FpeEngine { protected readonly IBlockCipher baseCipher; protected bool forEncryption; protected FpeParameters fpeParameters; protected FpeEngine(IBlockCipher baseCipher) { this.baseCipher = baseCipher; } public virtual int ProcessBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff) { if (fpeParameters == null) throw new InvalidOperationException("FPE engine not initialized"); if (length < 0) throw new ArgumentException("cannot be negative", "length"); if (inBuf == null) throw new ArgumentNullException("inBuf"); if (outBuf == null) throw new ArgumentNullException("outBuf"); Check.DataLength(inBuf, inOff, length, "input buffer too short"); Check.OutputLength(outBuf, outOff, length, "output buffer too short"); if (forEncryption) return EncryptBlock(inBuf, inOff, length, outBuf, outOff); return DecryptBlock(inBuf, inOff, length, outBuf, outOff); } protected static bool IsOverrideSet(string propName) { string environmentVariable = Platform.GetEnvironmentVariable(propName); if (environmentVariable != null) return Platform.EqualsIgnoreCase("true", environmentVariable); return false; } public abstract void Init(bool forEncryption, ICipherParameters parameters); protected abstract int EncryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff); protected abstract int DecryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff); } }