// Token: 0x06000077 RID: 119 RVA: 0x00008E70 File Offset: 0x00007070
public virtual void Init(bool forEncryption, ICipherParameters parameters)
{
this.forEncryption = forEncryption;
this.macBlock = null;
if (parameters is AeadParameters)
{
AeadParameters aeadParameters = (AeadParameters)parameters;
this.nonce = aeadParameters.GetNonce();
this.A = aeadParameters.GetAssociatedText();
int num = aeadParameters.MacSize;
if (num < 96 || num > 128 || num % 8 != 0)
{
throw new ArgumentException("Invalid value for MAC size: " + num.ToString());
}
this.macSize = num / 8;
this.keyParam = aeadParameters.Key;
}
else
{
if (!(parameters is ParametersWithIV))
{
throw new ArgumentException("invalid parameters passed to GCM");
}
ParametersWithIV parametersWithIV = (ParametersWithIV)parameters;
this.nonce = parametersWithIV.GetIV();
this.A = null;
this.macSize = 16;
this.keyParam = (KeyParameter)parametersWithIV.Parameters;
}
int num2 = forEncryption ? 16 : (16 + this.macSize);
this.bufBlock = new byte[num2];
if (this.nonce == null || this.nonce.Length < 1)
{
throw new ArgumentException("IV must be at least 1 byte");
}
if (this.A == null)
{
this.A = new byte[0];
}
this.cipher.Init(true, this.keyParam);
this.H = new byte[16];
this.cipher.ProcessBlock(this.H, 0, this.H, 0);
this.multiplier.Init(this.H);
this.initS = this.gHASH(this.A);
if (this.nonce.Length == 12)
{
this.J0 = new byte[16];
Array.Copy(this.nonce, 0, this.J0, 0, this.nonce.Length);
this.J0[15] = 1;
}
else
{
this.J0 = this.gHASH(this.nonce);
byte[] array = new byte[16];
GcmBlockCipher.packLength((ulong)((long)this.nonce.Length * 8L), array, 8);
GcmUtilities.Xor(this.J0, array);
this.multiplier.MultiplyH(this.J0);
}
this.S = Arrays.Clone(this.initS);
this.counter = Arrays.Clone(this.J0);
this.bufOff = 0;
this.totalLength = 0UL;
}