/// <summary>
/// Extracts the memory cost, time cost, etc. used to generate the Argon2 hash.
/// <param name="formattedHash">An encoded Argon2 hash created by the Hash method</param>
/// <returns>The hash metadata or null if the formattedHash was not a valid encoded Argon2 hash</returns>
/// </summary>
public static HashMetadata ExtractMetadata(string formattedHash)
{
CheckNull("ExtractMetadata", "formattedHash", formattedHash);
var context = new Argon2Context
{
Out = Marshal.AllocHGlobal(formattedHash.Length), // ensure the space to hold the hash is long enough
OutLen = (uint)formattedHash.Length,
Pwd = Marshal.AllocHGlobal(1),
PwdLen = 1,
Salt = Marshal.AllocHGlobal(formattedHash.Length), // ensure the space to hold the salt is long enough
SaltLen = (uint)formattedHash.Length,
Secret = Marshal.AllocHGlobal(1),
SecretLen = 1,
AssocData = Marshal.AllocHGlobal(1),
AssocDataLen = 1,
TimeCost = 0,
MemoryCost = 0,
Lanes = 0,
Threads = 0
};
try
{
var type = (formattedHash.StartsWith("$argon2i") ? Argon2Type.Argon2i : Argon2Type.Argon2d);
var result = (Argon2Error)crypto_decode_string(context, Encoding.ASCII.GetBytes(formattedHash + "\0"), (int)type);
if (result != Argon2Error.OK)
{
return(null);
}
var salt = new byte[context.SaltLen];
var hash = new byte[context.OutLen];
Marshal.Copy(context.Salt, salt, 0, salt.Length);
Marshal.Copy(context.Out, hash, 0, hash.Length);
return(new HashMetadata
{
ArgonType = type,
MemoryCost = context.MemoryCost,
TimeCost = context.TimeCost,
Parallelism = context.Threads,
Salt = salt,
Hash = hash
});
}
finally
{
Marshal.FreeHGlobal(context.Out);
Marshal.FreeHGlobal(context.Pwd);
Marshal.FreeHGlobal(context.Salt);
Marshal.FreeHGlobal(context.Secret);
Marshal.FreeHGlobal(context.AssocData);
}
}
private static extern int crypto_decode_string(Argon2Context ctx, byte[] str, int type);
/// <summary>
/// Extracts the memory cost, time cost, etc. used to generate the Argon2 hash.
/// <param name="formattedHash">An encoded Argon2 hash created by the Hash method</param>
/// <returns>The hash metadata or null if the formattedHash was not a valid encoded Argon2 hash</returns>
/// </summary>
public static HashMetadata ExtractMetadata(string formattedHash)
{
CheckNull("ExtractMetadata", "formattedHash", formattedHash);
var context = new Argon2Context
{
Out = Marshal.AllocHGlobal(formattedHash.Length), // ensure the space to hold the hash is long enough
OutLen = (uint)formattedHash.Length,
Pwd = Marshal.AllocHGlobal(1),
PwdLen = 1,
Salt = Marshal.AllocHGlobal(formattedHash.Length), // ensure the space to hold the salt is long enough
SaltLen = (uint)formattedHash.Length,
Secret = Marshal.AllocHGlobal(1),
SecretLen = 1,
AssocData = Marshal.AllocHGlobal(1),
AssocDataLen = 1,
TimeCost = 0,
MemoryCost = 0,
Lanes = 0,
Threads = 0
};
try
{
var type = (formattedHash.StartsWith("$argon2i") ? Argon2Type.Argon2i : Argon2Type.Argon2d);
var result = (Argon2Error)crypto_decode_string(context, Encoding.ASCII.GetBytes(formattedHash + "\0"), (int)type);
if (result != Argon2Error.OK)
return null;
var salt = new byte[context.SaltLen];
var hash = new byte[context.OutLen];
Marshal.Copy(context.Salt, salt, 0, salt.Length);
Marshal.Copy(context.Out, hash, 0, hash.Length);
return new HashMetadata
{
ArgonType = type,
MemoryCost = context.MemoryCost,
TimeCost = context.TimeCost,
Parallelism = context.Threads,
Salt = salt,
Hash = hash
};
}
finally
{
Marshal.FreeHGlobal(context.Out);
Marshal.FreeHGlobal(context.Pwd);
Marshal.FreeHGlobal(context.Salt);
Marshal.FreeHGlobal(context.Secret);
Marshal.FreeHGlobal(context.AssocData);
}
}
private static extern int crypto_decode_string(Argon2Context ctx, byte[] str, int type);
