From 9880d28a5efafec714679f52290541097dbb2b75 Mon Sep 17 00:00:00 2001
From: Erik Zhang <erik@neo.org>
Date: Thu, 14 Jul 2022 13:56:12 +0800
Subject: [PATCH] Add serialization methods for Fp2, Fp6, Fp12 and Gt (#2)

---
 src/Neo.Cryptography.BLS12_381/Fp12.cs | 24 ++++++++++++++++++++++++
 src/Neo.Cryptography.BLS12_381/Fp2.cs  | 24 ++++++++++++++++++++++++
 src/Neo.Cryptography.BLS12_381/Fp6.cs  | 26 ++++++++++++++++++++++++++
 src/Neo.Cryptography.BLS12_381/Gt.cs   | 15 +++++++++++++++
 4 files changed, 89 insertions(+)

diff --git a/src/Neo.Cryptography.BLS12_381/Fp12.cs b/src/Neo.Cryptography.BLS12_381/Fp12.cs
index 4fb38ba..60ad044 100644
--- a/src/Neo.Cryptography.BLS12_381/Fp12.cs
+++ b/src/Neo.Cryptography.BLS12_381/Fp12.cs
@@ -44,6 +44,15 @@ public Fp12(in Fp6 c0, in Fp6 c1)
         C1 = c1;
     }
 
+    public static Fp12 FromBytes(ReadOnlySpan<byte> data)
+    {
+        if (data.Length != Size)
+            throw new FormatException($"The argument `{nameof(data)}` should contain {Size} bytes.");
+        Fp6 c0 = Fp6.FromBytes(data[Fp6.Size..]);
+        Fp6 c1 = Fp6.FromBytes(data[..Fp6.Size]);
+        return new(in c0, in c1);
+    }
+
     public static bool operator ==(in Fp12 a, in Fp12 b)
     {
         return a.C0 == b.C0 & a.C1 == b.C1;
@@ -70,6 +79,21 @@ public override int GetHashCode()
         return C0.GetHashCode() ^ C1.GetHashCode();
     }
 
+    public byte[] ToArray()
+    {
+        byte[] result = GC.AllocateUninitializedArray<byte>(Size);
+        TryWrite(result);
+        return result;
+    }
+
+    public bool TryWrite(Span<byte> buffer)
+    {
+        if (buffer.Length < Size) return false;
+        C0.TryWrite(buffer[Fp6.Size..Size]);
+        C1.TryWrite(buffer[0..Fp6.Size]);
+        return true;
+    }
+
     public static Fp12 Random(RandomNumberGenerator rng)
     {
         return new(Fp6.Random(rng), Fp6.Random(rng));
diff --git a/src/Neo.Cryptography.BLS12_381/Fp2.cs b/src/Neo.Cryptography.BLS12_381/Fp2.cs
index 49adf3e..8c318a5 100644
--- a/src/Neo.Cryptography.BLS12_381/Fp2.cs
+++ b/src/Neo.Cryptography.BLS12_381/Fp2.cs
@@ -35,6 +35,15 @@ public Fp2(in Fp c0, in Fp c1)
         C1 = c1;
     }
 
+    public static Fp2 FromBytes(ReadOnlySpan<byte> data)
+    {
+        if (data.Length != Size)
+            throw new FormatException($"The argument `{nameof(data)}` should contain {Size} bytes.");
+        Fp c0 = Fp.FromBytes(data[Fp.Size..]);
+        Fp c1 = Fp.FromBytes(data[..Fp.Size]);
+        return new(in c0, in c1);
+    }
+
     public static Fp2 Random(RandomNumberGenerator rng)
     {
         return new(Fp.Random(rng), Fp.Random(rng));
@@ -66,6 +75,21 @@ public override int GetHashCode()
         return C0.GetHashCode() ^ C1.GetHashCode();
     }
 
+    public byte[] ToArray()
+    {
+        byte[] result = GC.AllocateUninitializedArray<byte>(Size);
+        TryWrite(result);
+        return result;
+    }
+
+    public bool TryWrite(Span<byte> buffer)
+    {
+        if (buffer.Length < Size) return false;
+        C0.TryWrite(buffer[Fp.Size..Size]);
+        C1.TryWrite(buffer[0..Fp.Size]);
+        return true;
+    }
+
     public Fp2 FrobeniusMap()
     {
         // This is always just a conjugation. If you're curious why, here's
diff --git a/src/Neo.Cryptography.BLS12_381/Fp6.cs b/src/Neo.Cryptography.BLS12_381/Fp6.cs
index 0c54125..3261e30 100644
--- a/src/Neo.Cryptography.BLS12_381/Fp6.cs
+++ b/src/Neo.Cryptography.BLS12_381/Fp6.cs
@@ -42,6 +42,16 @@ public Fp6(in Fp2 c0, in Fp2 c1, in Fp2 c2)
         C2 = c2;
     }
 
+    public static Fp6 FromBytes(ReadOnlySpan<byte> data)
+    {
+        if (data.Length != Size)
+            throw new FormatException($"The argument `{nameof(data)}` should contain {Size} bytes.");
+        Fp2 c0 = Fp2.FromBytes(data[(Fp2.Size * 2)..]);
+        Fp2 c1 = Fp2.FromBytes(data[Fp2.Size..(Fp2.Size * 2)]);
+        Fp2 c2 = Fp2.FromBytes(data[..Fp2.Size]);
+        return new(in c0, in c1, in c2);
+    }
+
     public static bool operator ==(in Fp6 a, in Fp6 b)
     {
         return a.C0 == b.C0 & a.C1 == b.C1 & a.C2 == b.C2;
@@ -68,6 +78,22 @@ public override int GetHashCode()
         return C0.GetHashCode() ^ C1.GetHashCode() ^ C2.GetHashCode();
     }
 
+    public byte[] ToArray()
+    {
+        byte[] result = GC.AllocateUninitializedArray<byte>(Size);
+        TryWrite(result);
+        return result;
+    }
+
+    public bool TryWrite(Span<byte> buffer)
+    {
+        if (buffer.Length < Size) return false;
+        C0.TryWrite(buffer[(Fp2.Size * 2)..Size]);
+        C1.TryWrite(buffer[Fp2.Size..(Fp2.Size * 2)]);
+        C2.TryWrite(buffer[0..Fp2.Size]);
+        return true;
+    }
+
     public static Fp6 Random(RandomNumberGenerator rng)
     {
         return new(Fp2.Random(rng), Fp2.Random(rng), Fp2.Random(rng));
diff --git a/src/Neo.Cryptography.BLS12_381/Gt.cs b/src/Neo.Cryptography.BLS12_381/Gt.cs
index 38dd813..f0f3ce8 100644
--- a/src/Neo.Cryptography.BLS12_381/Gt.cs
+++ b/src/Neo.Cryptography.BLS12_381/Gt.cs
@@ -20,6 +20,11 @@ public Gt(in Fp12 f)
         Value = f;
     }
 
+    public static Gt FromBytes(ReadOnlySpan<byte> data)
+    {
+        return new(Fp12.FromBytes(data));
+    }
+
     public static bool operator ==(in Gt a, in Gt b)
     {
         return a.Value == b.Value;
@@ -46,6 +51,16 @@ public override int GetHashCode()
         return Value.GetHashCode();
     }
 
+    public byte[] ToArray()
+    {
+        return Value.ToArray();
+    }
+
+    public bool TryWrite(Span<byte> buffer)
+    {
+        return Value.TryWrite(buffer);
+    }
+
     public static Gt Random(RandomNumberGenerator rng)
     {
         while (true)