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using System;
using System.Collections;
using System.IO;
using Org.BouncyCastle.Tls.Crypto;
using Org.BouncyCastle.Utilities;
namespace Org.BouncyCastle.Tls
{
public sealed class OfferedPsks
{
private readonly IList m_identities;
private readonly IList m_binders;
public OfferedPsks(IList identities)
: this(identities, null)
{
}
private OfferedPsks(IList identities, IList binders)
{
if (null == identities || identities.Count < 1)
throw new ArgumentException("cannot be null or empty", "identities");
if (null != binders && identities.Count != binders.Count)
throw new ArgumentException("must be the same length as 'identities' (or null)", "binders");
this.m_identities = identities;
this.m_binders = binders;
}
public IList Binders
{
get { return m_binders; }
}
public IList Identities
{
get { return m_identities; }
}
/// <exception cref="IOException"/>
public void Encode(Stream output)
{
// identities
{
int lengthOfIdentitiesList = 0;
foreach (PskIdentity identity in m_identities)
{
lengthOfIdentitiesList += identity.GetEncodedLength();
}
TlsUtilities.CheckUint16(lengthOfIdentitiesList);
TlsUtilities.WriteUint16(lengthOfIdentitiesList, output);
foreach (PskIdentity identity in m_identities)
{
identity.Encode(output);
}
}
// binders
if (null != m_binders)
{
int lengthOfBindersList = 0;
foreach (byte[] binder in m_binders)
{
lengthOfBindersList += 1 + binder.Length;
}
TlsUtilities.CheckUint16(lengthOfBindersList);
TlsUtilities.WriteUint16(lengthOfBindersList, output);
foreach (byte[] binder in m_binders)
{
TlsUtilities.WriteOpaque8(binder, output);
}
}
}
/// <exception cref="IOException"/>
internal static void EncodeBinders(Stream output, TlsCrypto crypto, TlsHandshakeHash handshakeHash,
TlsPsk[] psks, TlsSecret[] earlySecrets, int expectedLengthOfBindersList)
{
TlsUtilities.CheckUint16(expectedLengthOfBindersList);
TlsUtilities.WriteUint16(expectedLengthOfBindersList, output);
int lengthOfBindersList = 0;
for (int i = 0; i < psks.Length; ++i)
{
TlsPsk psk = psks[i];
TlsSecret earlySecret = earlySecrets[i];
// TODO[tls13-psk] Handle resumption PSKs
bool isExternalPsk = true;
int pskCryptoHashAlgorithm = TlsCryptoUtilities.GetHashForPrf(psk.PrfAlgorithm);
// TODO[tls13-psk] Cache the transcript hashes per algorithm to avoid duplicates for multiple PSKs
TlsHash hash = crypto.CreateHash(pskCryptoHashAlgorithm);
handshakeHash.CopyBufferTo(new TlsHashSink(hash));
byte[] transcriptHash = hash.CalculateHash();
byte[] binder = TlsUtilities.CalculatePskBinder(crypto, isExternalPsk, pskCryptoHashAlgorithm,
earlySecret, transcriptHash);
lengthOfBindersList += 1 + binder.Length;
TlsUtilities.WriteOpaque8(binder, output);
}
if (expectedLengthOfBindersList != lengthOfBindersList)
throw new TlsFatalAlert(AlertDescription.internal_error);
}
/// <exception cref="IOException"/>
internal static int GetLengthOfBindersList(TlsPsk[] psks)
{
int lengthOfBindersList = 0;
for (int i = 0; i < psks.Length; ++i)
{
TlsPsk psk = psks[i];
int prfAlgorithm = psk.PrfAlgorithm;
int prfCryptoHashAlgorithm = TlsCryptoUtilities.GetHashForPrf(prfAlgorithm);
lengthOfBindersList += 1 + TlsCryptoUtilities.GetHashOutputSize(prfCryptoHashAlgorithm);
}
TlsUtilities.CheckUint16(lengthOfBindersList);
return lengthOfBindersList;
}
/// <exception cref="IOException"/>
public static OfferedPsks Parse(Stream input)
{
IList identities = Platform.CreateArrayList();
{
int totalLengthIdentities = TlsUtilities.ReadUint16(input);
if (totalLengthIdentities < 7)
throw new TlsFatalAlert(AlertDescription.decode_error);
byte[] identitiesData = TlsUtilities.ReadFully(totalLengthIdentities, input);
MemoryStream buf = new MemoryStream(identitiesData, false);
do
{
PskIdentity identity = PskIdentity.Parse(buf);
identities.Add(identity);
}
while (buf.Position < buf.Length);
}
IList binders = Platform.CreateArrayList();
{
int totalLengthBinders = TlsUtilities.ReadUint16(input);
if (totalLengthBinders < 33)
throw new TlsFatalAlert(AlertDescription.decode_error);
byte[] bindersData = TlsUtilities.ReadFully(totalLengthBinders, input);
MemoryStream buf = new MemoryStream(bindersData, false);
do
{
byte[] binder = TlsUtilities.ReadOpaque8(input, 32);
binders.Add(binder);
}
while (buf.Position < buf.Length);
}
return new OfferedPsks(identities, binders);
}
}
}
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