diff --git a/README.md b/README.md
index aa74ec69d..96e7e0a66 100644
--- a/README.md
+++ b/README.md
@@ -3,6 +3,4 @@ Atmosphère-NX
 
 ![License](https://img.shields.io/badge/License-GPLv2-blue.svg)
 
-This is a placeholder repo reserved for any/all development work I do pertaining to customized firmware on the Nintendo Switch.
-
-Currently, I do not know on what timeline commits to this repository will appear.
+This is a placeholder repo reserved for any/all development work I do pertaining to customized firmware on the Nintendo Switch.
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diff --git a/exosphere/README.md b/exosphere/README.md
new file mode 100644
index 000000000..1bc891504
--- /dev/null
+++ b/exosphere/README.md
@@ -0,0 +1,6 @@
+Exosphere
+=====
+
+![License](https://img.shields.io/badge/License-GPLv2-blue.svg)
+
+Exosphere is a Secure Monitor implementation for the Nintendo Switch.
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diff --git a/exosphere/se.h b/exosphere/se.h
new file mode 100644
index 000000000..be7d155ac
--- /dev/null
+++ b/exosphere/se.h
@@ -0,0 +1,32 @@
+#ifndef EXOSPHERE_SE_H
+#define EXOSPHERE_SE_H
+
+/* Exosphere driver for the Tegra X1 security engine. */
+
+/* TODO: Define constants for the C driver. */
+
+/* WIP, API subject to change. */
+
+#define KEYSLOT_AES_MAX 0x10
+#define KEYSLOT_RSA_MAX 0x2
+
+void set_security_engine_address(void *security_engine);
+
+void set_aes_keyslot_flags(unsigned int keyslot, unsigned int flags);
+void set_rsa_keyslot_flags(unsigned int keyslot, unsigned int flags);
+void clear_aes_keyslot(unsigned int keyslot);
+void clear_rsa_keyslot(unsigned int keyslot);
+
+void set_aes_keyslot(unsigned int keyslot, const char *key, unsigned int key_size);
+void crypt_data_into_keyslot(unsigned int keyslot, )
+void set_rsa_keyslot(unsigned int keyslot, const char *modulus, unsigned int modulus_size, const char *exp, unsigned int exp_size);
+void set_aes_keyslot_iv(unsigned int keyslot, const char *iv, unsigned int iv_size);
+void set_se_ctr(const unsigned int *ctr);
+
+void se_crypt_aes(unsigned int keyslot, char *dst, unsigned int dst_size, const char *src, unsigned int src_size, unsigned int config, unsigned int mode, unsigned int (*callback)(void));
+void se_exp_mod(unsigned int keyslot, char *buf, unsigned int size, unsigned int (*callback)(void));
+
+/* TODO: SE context save API, consider extending AES API for secure world vs non-secure world operations. */
+/* In particular, smc_crypt_aes takes in raw DMA lists, and we need to support that. */
+
+#endif /* EXOSPHERE_SE_H */
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