diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..142a5bb
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,39 @@
+[submodule "external/mapm"]
+	path = external/mapm
+	url = https://github.com/LuaDist/mapm.git
+[submodule "external/mpir"]
+	path = external/mpir
+	url = https://github.com/wbhart/mpir.git
+[submodule "external/libtommath"]
+	path = external/libtommath
+	url = https://github.com/libtom/libtommath.git
+[submodule "external/libgcrypt"]
+	path = external/libgcrypt
+	url = https://dev.gnupg.org/source/libgcrypt.git
+[submodule "external/openssl"]
+	path = external/openssl
+	url = https://github.com/openssl/openssl.git
+[submodule "external/arbitraire"]
+	path = external/arbitraire
+	url = https://github.com/hlibc/arbitraire.git
+[submodule "external/mbedtls"]
+	path = external/mbedtls
+	url = https://github.com/ARMmbed/mbedtls
+[submodule "external/ramp"]
+	path = external/ramp
+	url = https://github.com/Aatch/ramp.git
+[submodule "external/imath"]
+	path = external/imath
+	url = https://github.com/creachadair/imath.git
+[submodule "external/hebimath"]
+	path = external/hebimath
+	url = https://github.com/suiginsoft/hebimath.git
+[submodule "external/bsdnt"]
+	path = external/bsdnt
+	url = https://github.com/wbhart/bsdnt.git
+[submodule "external/rug"]
+	path = external/rug
+	url = https://gitlab.com/tspiteri/rug.git
+[submodule "external/num"]
+	path = external/num
+	url = https://github.com/rust-num/num.git
diff --git a/external/arbitraire b/external/arbitraire
new file mode 160000
index 0000000..e79eacb
--- /dev/null
+++ b/external/arbitraire
@@ -0,0 +1 @@
+Subproject commit e79eacb1401698ebe611f6a4ee3aa4a0d9f2eaff
diff --git a/external/bsdnt b/external/bsdnt
new file mode 160000
index 0000000..de98bde
--- /dev/null
+++ b/external/bsdnt
@@ -0,0 +1 @@
+Subproject commit de98bde16fe65049a2ae843f782a439ea64ba419
diff --git a/external/hebimath b/external/hebimath
new file mode 160000
index 0000000..cecedd0
--- /dev/null
+++ b/external/hebimath
@@ -0,0 +1 @@
+Subproject commit cecedd0669019d77dac1c584d01edf945977fca0
diff --git a/external/imath b/external/imath
new file mode 160000
index 0000000..49fbecb
--- /dev/null
+++ b/external/imath
@@ -0,0 +1 @@
+Subproject commit 49fbecb54b0ab511cd9a796b02aaa5b99ebb02bf
diff --git a/external/libgcrypt b/external/libgcrypt
new file mode 160000
index 0000000..b878a98
--- /dev/null
+++ b/external/libgcrypt
@@ -0,0 +1 @@
+Subproject commit b878a986f3ab2c35aff89c7f66f137a91542ed5b
diff --git a/external/libtommath b/external/libtommath
new file mode 160000
index 0000000..91d953e
--- /dev/null
+++ b/external/libtommath
@@ -0,0 +1 @@
+Subproject commit 91d953ed73b4ff349457c52555acf12e2b974c06
diff --git a/external/mapm b/external/mapm
new file mode 160000
index 0000000..d3627e8
--- /dev/null
+++ b/external/mapm
@@ -0,0 +1 @@
+Subproject commit d3627e8e95ecae02581452e88bfe819e0cd8698a
diff --git a/external/mbedtls b/external/mbedtls
new file mode 160000
index 0000000..1cd7bea
--- /dev/null
+++ b/external/mbedtls
@@ -0,0 +1 @@
+Subproject commit 1cd7bea2b1db288e64824b1fca842e6510da028d
diff --git a/external/mpir b/external/mpir
new file mode 160000
index 0000000..55fe6a9
--- /dev/null
+++ b/external/mpir
@@ -0,0 +1 @@
+Subproject commit 55fe6a9f52ca532a611a89f67186ed915bbf1123
diff --git a/external/num b/external/num
new file mode 160000
index 0000000..76a3cff
--- /dev/null
+++ b/external/num
@@ -0,0 +1 @@
+Subproject commit 76a3cffa5bddeb8b9b8348e57a2f42e0bbc77195
diff --git a/external/openssl b/external/openssl
new file mode 160000
index 0000000..555cbb3
--- /dev/null
+++ b/external/openssl
@@ -0,0 +1 @@
+Subproject commit 555cbb328ee2eaa9356cd23e2194c1600653c500
diff --git a/external/ramp b/external/ramp
new file mode 160000
index 0000000..a8f2a50
--- /dev/null
+++ b/external/ramp
@@ -0,0 +1 @@
+Subproject commit a8f2a50d31821c9a60a7d4bc9bdda1a479ecf197
diff --git a/external/rug b/external/rug
new file mode 160000
index 0000000..de4068e
--- /dev/null
+++ b/external/rug
@@ -0,0 +1 @@
+Subproject commit de4068e7911a689a0ee73381dbca539311aa8b7c