[Test] public void Base32()
{
{
var data = new byte[] { 0xff };
var enc = Base32Encoding.ToString(data);
var dec = Base32Encoding.ToBytes(enc);
Assert.Equal(enc.Length, Base32Encoding.EncodedLength(data.Length));
Assert.Equal(dec.Length, Base32Encoding.DecodedLength(enc));
Assert.Equal(0, Array_.Compare(data, 0, data.Length, dec, 0, dec.Length));
}
{
var data = new byte[256];
for (int i = 0; i != data.Length; ++i)
{
data[i] = (byte)i;
}
var enc = Base32Encoding.ToString(data);
var dec = Base32Encoding.ToBytes(enc);
Assert.Equal(enc.Length, Base32Encoding.EncodedLength(data.Length));
Assert.Equal(dec.Length, Base32Encoding.DecodedLength(enc));
Assert.Equal(0, Array_.Compare(data, 0, data.Length, dec, 0, dec.Length));
}
var rand = new Random(42);
for (int i = 0; i != 100; ++i)
{
var data = new byte[rand.Next(16000)];
rand.NextBytes(data);
var enc = Base32Encoding.ToString(data);
var dec = Base32Encoding.ToBytes(enc);
Assert.Equal(enc.Length, Base32Encoding.EncodedLength(data.Length));
Assert.Equal(dec.Length, Base32Encoding.DecodedLength(enc));
Assert.Equal(0, Array_.Compare(data, 0, data.Length, dec, 0, dec.Length));
}
}
public void ByteArrayCompare()
{
byte[] lhs = new byte[] { 1, 2, 3, 4, 5 };
byte[] rhs = new byte[] { 3, 4, 5, 6, 7 };
Assert.Equal(-1, Array_.Compare(lhs, 0, 5, rhs, 0, 5));
Assert.Equal(0, Array_.Compare(lhs, 2, 3, rhs, 0, 3));
Assert.Equal(1, Array_.Compare(lhs, 3, 2, rhs, 0, 2));
Assert.Equal(-1, Array_.Compare(lhs, 2, 3, rhs, 0, 4));
Assert.Equal(1, Array_.Compare(lhs, 2, 3, rhs, 0, 2));
}
/// <summary>Verify that a file has a valid signature</summary>
public static bool Validate(string filepath, string public_key, bool thrw = true)
{
// Create the 'Crypto' service
var alg = new RSACryptoServiceProvider();
alg.FromXmlString(public_key);
var key_size_bytes = alg.KeySize / 8;
// Read the file into memory (no fancy streaming...)
var filebuf = File.ReadAllBytes(filepath);
var length = filebuf.Length;
// The total length of the signature in bytes
var sig_length = key_size_bytes + SignatureId.Length;
// Check whether the file has a signature
if (length >= sig_length && Array_.Compare(
filebuf, length - sig_length, SignatureId.Length,
SignatureId, 0, SignatureId.Length) == 0)
{
length -= sig_length;
}
else
{
if (thrw)
{
throw new VerificationException("File is not signed");
}
return(false);
}
// Validate the signature
var buf = filebuf.Take(length).ToArray();
var sig = filebuf.Skip(length + SignatureId.Length).Take(key_size_bytes).ToArray();
bool valid = alg.VerifyData(buf, new SHA256CryptoServiceProvider(), sig);
if (thrw && !valid)
{
throw new VerificationException("File signature incorrect");
}
return(valid);
}
// Disabled until 'GenerateRSAKeyPair' is upgraded [Test]
public void SignFile()
{
// These would normally be stored as files and read into
// a string using File.ReadAllText()
Crypt.GenerateRSAKeyPair(out var pub, out var prv);
const string filepath = "tmp.bin";
var data = new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
try
{
// Create a file to sign
using (var fs = new FileStream(filepath, FileMode.Create, FileAccess.Write))
fs.Write(data, 0, data.Length);
// Sign the file
Crypt.SignFile(filepath, prv);
// Check that the start of the file is the same
var buf1 = File.ReadAllBytes(filepath);
Assert.True(Array_.Compare(buf1, 0, data.Length, data, 0, data.Length) == 0);
// Verify the signed file using the public key
Assert.True(Crypt.Validate(filepath, pub));
// Sign it again to make sure the function handles the case that the signature is already there
Crypt.SignFile(filepath, prv);
// Check that the whole file is the same
var buf2 = File.ReadAllBytes(filepath);
Assert.True(Array_.Compare(buf2, 0, buf2.Length, buf1, 0, buf1.Length) == 0);
// Verify the signed file using the public key
Assert.True(Crypt.Validate(filepath, pub));
}
finally
{
File.Delete(filepath);
}
}
/// <summary>Attaches a signature to the end of a file</summary>
public static void SignFile(string filepath, string private_key)
{
// Create the 'Crypto' service
var alg = new RSACryptoServiceProvider();
alg.FromXmlString(private_key);
var key_size_bytes = alg.KeySize / 8;
// Read the file into memory (no fancy streaming...)
var filebuf = File.ReadAllBytes(filepath);
var length = filebuf.Length;
// The total length of the signature in bytes
var sig_length = key_size_bytes + SignatureId.Length;
// Check whether the file has an existing signature
// If so, shorten the length of file buf that's signed
if (length >= sig_length && Array_.Compare(
filebuf, length - sig_length, SignatureId.Length,
SignatureId, 0, SignatureId.Length) == 0)
{
length -= sig_length;
}
// Generate the signature
var buf = filebuf.Take(length).ToArray();
var sig = alg.SignData(buf, new SHA256CryptoServiceProvider());
// Append the signature to the end of the file
using (var fs = new FileStream(filepath, FileMode.Open, FileAccess.Write))
{
fs.Seek(length, SeekOrigin.Begin);
fs.Write(SignatureId, 0, SignatureId.Length);
fs.Write(sig, 0, sig.Length);
}
}
