1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
using System;
using Org.BouncyCastle.Asn1;
using Org.BouncyCastle.Asn1.X509;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Crypto.Utilities;
namespace Org.BouncyCastle.Crypto.Agreement.Kdf
{
/**
* X9.63 based key derivation function for ECDH CMS.
*/
public sealed class ECDHKekGenerator
: IDerivationFunction
{
private readonly IDerivationFunction m_kdf;
private DerObjectIdentifier algorithm;
private int keySize;
private byte[] z;
public ECDHKekGenerator(IDigest digest)
{
m_kdf = new Kdf2BytesGenerator(digest);
}
public void Init(IDerivationParameters param)
{
DHKdfParameters parameters = (DHKdfParameters)param;
this.algorithm = parameters.Algorithm;
this.keySize = parameters.KeySize;
this.z = parameters.GetZ(); // TODO Clone?
}
public IDigest Digest => m_kdf.Digest;
public int GenerateBytes(byte[] outBytes, int outOff, int length)
{
Check.OutputLength(outBytes, outOff, length, "output buffer too small");
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
return GenerateBytes(outBytes.AsSpan(outOff, length));
#else
// TODO Create an ASN.1 class for this (RFC3278)
// ECC-CMS-SharedInfo
DerSequence s = new DerSequence(
new AlgorithmIdentifier(algorithm, DerNull.Instance),
new DerTaggedObject(true, 2, new DerOctetString(Pack.UInt32_To_BE((uint)keySize))));
m_kdf.Init(new KdfParameters(z, s.GetDerEncoded()));
return m_kdf.GenerateBytes(outBytes, outOff, length);
#endif
}
#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
public int GenerateBytes(Span<byte> output)
{
// TODO Create an ASN.1 class for this (RFC3278)
// ECC-CMS-SharedInfo
DerSequence s = new DerSequence(
new AlgorithmIdentifier(algorithm, DerNull.Instance),
new DerTaggedObject(true, 2, new DerOctetString(Pack.UInt32_To_BE((uint)keySize))));
m_kdf.Init(new KdfParameters(z, s.GetDerEncoded()));
return m_kdf.GenerateBytes(output);
}
#endif
}
}
|
