// Token: 0x060001DB RID: 475 RVA: 0x0000C99C File Offset: 0x0000AB9C
public int DoFinal(byte[] output, int outOff)
{
int num = this.bufOff;
if (!this.forEncryption)
{
if (num < this.macSize)
{
throw new InvalidCipherTextException("data too short");
}
num -= this.macSize;
}
if (num > 0)
{
byte[] array = new byte[16];
Array.Copy(this.bufBlock, 0, array, 0, num);
this.gCTRBlock(array, num, output, outOff);
}
byte[] array2 = new byte[16];
GcmBlockCipher.packLength((ulong)((long)this.A.Length * 8L), array2, 0);
GcmBlockCipher.packLength(this.totalLength * 8UL, array2, 8);
GcmUtilities.Xor(this.S, array2);
this.multiplier.MultiplyH(this.S);
byte[] array3 = new byte[16];
this.cipher.ProcessBlock(this.J0, 0, array3, 0);
GcmUtilities.Xor(array3, this.S);
int num2 = num;
this.macBlock = new byte[this.macSize];
Array.Copy(array3, 0, this.macBlock, 0, this.macSize);
if (this.forEncryption)
{
Array.Copy(this.macBlock, 0, output, outOff + this.bufOff, this.macSize);
num2 += this.macSize;
}
else
{
byte[] array4 = new byte[this.macSize];
Array.Copy(this.bufBlock, num, array4, 0, this.macSize);
if (!Arrays.ConstantTimeAreEqual(this.macBlock, array4))
{
throw new InvalidCipherTextException("mac check in GCM failed");
}
}
this.Reset(false);
return(num2);
}
// Token: 0x060001D4 RID: 468 RVA: 0x0000C5F8 File Offset: 0x0000A7F8
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;
}
