Add existing HPKE project files

internal/mlkemtest/mlkemtest_fips140v1.0.go

@@ -0,0 +1,44 @@
+//go:build !go1.26 && fips140v1.0
+
+package mlkemtest
+
+import (
+	"crypto/mlkem"
+	"errors"
+	"unsafe"
+)
+
+// Reach ungracefully into the internals of crypto/internal/fips140/mlkem to
+// perform derandomized encapsulation, which will be exposed in Go 1.26.
+
+func Encapsulate768(ek *mlkem.EncapsulationKey768, rand []byte) (sharedKey, ciphertext []byte, err error) {
+	if len(rand) != 32 {
+		return nil, nil, errors.New("invalid ML-KEM-768 randomness size")
+	}
+	key := (*mlkem768EncapsulationKey)(unsafe.Pointer(ek))
+	sharedKey, ciphertext = mlkem768EncapsulateInternal(key.key, (*[32]byte)(rand))
+	return sharedKey, ciphertext, nil
+}
+
+type mlkem768EncapsulationKey struct {
+	key unsafe.Pointer // *crypto/internal/fips140/v1.0.0-c2097c7c/mlkem.EncapsulationKey768
+}
+
+//go:linkname mlkem768EncapsulateInternal crypto/internal/fips140/v1.0.0-c2097c7c/mlkem.(*EncapsulationKey768).EncapsulateInternal
+func mlkem768EncapsulateInternal(ek unsafe.Pointer, m *[32]byte) (sharedKey, ciphertext []byte)
+
+func Encapsulate1024(ek *mlkem.EncapsulationKey1024, rand []byte) (sharedKey, ciphertext []byte, err error) {
+	if len(rand) != 32 {
+		return nil, nil, errors.New("invalid ML-KEM-1024 randomness size")
+	}
+	key := (*mlkem1024EncapsulationKey)(unsafe.Pointer(ek))
+	sharedKey, ciphertext = mlkem1024EncapsulateInternal(key.key, (*[32]byte)(rand))
+	return sharedKey, ciphertext, nil
+}
+
+type mlkem1024EncapsulationKey struct {
+	key unsafe.Pointer // *crypto/internal/fips140/v1.0.0-c2097c7c/mlkem.EncapsulationKey1024
+}
+
+//go:linkname mlkem1024EncapsulateInternal crypto/internal/fips140/v1.0.0-c2097c7c/mlkem.(*EncapsulationKey1024).EncapsulateInternal
+func mlkem1024EncapsulateInternal(ek unsafe.Pointer, m *[32]byte) (sharedKey, ciphertext []byte)