fixing convert methods

Project.toml

@@ -1,7 +1,7 @@
 name = "CryptoGroups"
 uuid = "bc997328-bedd-407e-bcd3-5758e064a52d"
 authors = ["Janis Erdmanis <[email protected]>"]
-version = "0.5.2"
+version = "0.5.3"
 
 [deps]
 CryptoPRG = "d846c407-34c1-46cb-aa27-d51818cc05e2"

src/Curves/ecpoint.jl

@@ -176,7 +176,7 @@ end
 
 Base.:*(n::Integer, x::ECPoint; skip_validation = false) = *(x, n; skip_validation)
 
-Base.convert(::Type{ECPoint{P, S}}, x::NTuple{2}; allow_zero=false) where {P <: AbstractPoint, S} = ECPoint{P, S}(convert(P, x); allow_zero)
+Base.convert(::Type{ECPoint{P, S}}, x; allow_zero=false) where {P <: AbstractPoint, S} = ECPoint{P, S}(convert(P, x); allow_zero)
 Base.convert(::Type{P}, x::P) where P <: ECPoint = x 
 
 """

src/groups.jl

@@ -123,7 +123,7 @@ Converts representation of `x` into a group element type `G`. The conversion is
 group constructors. In case identity element needs to be read into `allow_one` flag can be used to allow constructing identity elements. 
 """
 Base.convert(::Type{ECGroup{P}}, x; allow_one=false) where P <: ECPoint = ECGroup{P}(convert(P, x; allow_zero=allow_one))
-Base.convert(::Type{G}, x::G) where G <: ECGroup = x
+Base.convert(::Type{G}, x::G) where G <: Group = x
 
 
 """
@@ -277,7 +277,7 @@ Converts modulus prime group element into octet representation. A padding is add
 """
 octet(x::PGroup) = int2octet(value(x), bitlength(modulus(x)))
 
-Base.convert(group::Type{<:PGroup}, element::Vector{UInt8}) = convert(group, octet2int(element))
+Base.convert(group::Type{<:PGroup}, element::Vector{UInt8}; allow_one::Bool=false) = convert(group, octet2int(element); allow_one)
 PGroup{S}(element::Vector{UInt8}) where S = convert(PGroup{S}, element)
 
 """

src/spec.jl

@@ -1,4 +1,4 @@
-using .Utils: StaticBitVector, StaticBigInt, static
+using .Utils: StaticBitVector, StaticBigInt, static, @check
 using .Fields: F2GNB, F2PB, @F2PB, FP, Field, PrimeField, BinaryField, tobits, value, reducer
 using .Curves: AbstractPoint, ECPoint, AffinePoint, Weierstrass, BinaryCurve, gx, gy, field, eq, a, b, cofactor
 using .Specs: MODP, Koblitz, ECP, EC2N, GroupSpec, PB, GNB, curve
@@ -160,3 +160,40 @@ spec(::Type{G}) where G <: PGroup = MODP(; p = modulus(G), q = order(G))
 (::Type{P})() where P <: ECPoint = P(generator(curve(name(P))))
 (::Type{ECGroup{P}})() where P <: ECPoint = ECGroup{P}(P())
 (::Type{G})() where G <: PGroup = G(generator(modp_spec(name(G))))
+
+
+# Shall be added to CryptoGroups
+iscompatable(x::GroupSpec, y::GroupSpec) = false
+
+function iscompatable(x::ECP, y::ECP)
+
+    x.p == y.p || return false
+    x.n == y.n || return false
+    x.a == y.a || return false
+    x.b == y.b || return false
+    x.cofactor == y.cofactor || return false
+
+    return true
+end
+
+function iscompatable(x::EC2N, y::EC2N)
+
+    x.basis == y.basis || return false
+    x.n == y.n || return false
+    x.a == y.a || return false
+    x.b == y.b || return false
+    x.cofactor == y.cofactor || return false
+
+    return true
+end
+
+iscompatable(G::Type{<:Group}, Q::Type{<:Group}) = iscompatable(spec(G), spec(Q))
+
+
+function _convert(G::Type{<:Group}, q::Group)
+    @check iscompatable(G, typeof(q)) "Conversion not possible as group types represent different specifications"
+    return G(octet(q))
+end
+
+Base.convert(G::Type{<:Group}, q::Group) = _convert(G, q)
+Base.convert(G::Type{ECGroup{P}}, q::Group) where P <: ECPoint = _convert(G, q)

test/groups.jl

@@ -1,5 +1,5 @@
 using Test
-import CryptoGroups: PGroup, @PGroup, order, modulus, value, concretize_type, Specs, generator
+import CryptoGroups: PGroup, @PGroup, order, modulus, value, concretize_type, Specs, generator, octet
 
 G = @PGroup{p = 23, q = 11}
 q = order(G)
@@ -57,6 +57,10 @@ function testgroup(g::G) where G <: Group
 
     @test one(g) * g == g
     @test g * one(g) == g
+
+    @test convert(G, value(one(G)); allow_one=true) == one(G)
+    @test convert(G, octet(one(G)); allow_one=true) == one(G)
+
 end
 
 G = @PGroup{p = 23, q = 11}