diff --git a/openssl-sys/src/crypto.rs b/openssl-sys/src/crypto.rs
index 6d8096f73a..d7281210ab 100644
--- a/openssl-sys/src/crypto.rs
+++ b/openssl-sys/src/crypto.rs
@@ -128,3 +128,9 @@ extern "C" {
 
     pub fn CRYPTO_memcmp(a: *const c_void, b: *const c_void, len: size_t) -> c_int;
 }
+
+#[repr(C)]
+pub struct CRYPTO_EX_DATA {
+    sk: *mut c_void,
+    dummy: c_int
+}
diff --git a/openssl-sys/src/engine.rs b/openssl-sys/src/engine.rs
new file mode 100644
index 0000000000..496f1d845a
--- /dev/null
+++ b/openssl-sys/src/engine.rs
@@ -0,0 +1,62 @@
+use libc::*;
+use *;
+
+extern "C" {
+    pub fn ENGINE_load_builtin_engines() -> ();
+    pub fn ENGINE_by_id(id: *const c_char) -> *mut ENGINE;
+
+    pub fn ENGINE_init(e: *mut ENGINE) -> c_int;
+    pub fn ENGINE_finish(e: *mut ENGINE) -> c_int;
+    pub fn ENGINE_free(e: *mut ENGINE) -> c_int;
+
+    pub fn ENGINE_ctrl_cmd(e: *mut ENGINE, cmd_name: *const c_char, i: c_long, p: *mut c_void, f: extern fn() -> (), cmd_optional: c_int) -> c_int;
+    pub fn ENGINE_ctrl_cmd_string(e: *mut ENGINE, cmd_name: *const c_char, arg: *const c_char, cmd_optional: c_int) -> c_int;
+
+    pub fn ENGINE_load_private_key(e: *mut ENGINE, key_id: *const c_char, ui_method: *mut UI_METHOD, callback_data: *mut c_void) -> *mut EVP_PKEY;
+    pub fn ENGINE_load_public_key(e: *mut ENGINE, key_id: *const c_char, ui_method: *mut UI_METHOD, callback_data: *mut c_void) -> *mut EVP_PKEY;
+    pub fn ENGINE_load_ssl_client_cert(
+        e: *mut ENGINE, ssl: *mut SSL, ca_dn: *mut stack_st_X509_NAME, pcert: *mut *mut X509, ppkey: *mut *mut EVP_PKEY,
+        pother: *mut *mut c_void, ui_method: *mut UI_METHOD, callback_data: *mut c_void
+    ) -> c_int;
+}
+
+#[repr(C)]
+pub struct UI_METHOD {
+    name: *const c_char,
+    ui_open_session: extern fn(ui: *mut UI) -> c_int,
+    ui_write_string: extern fn(ui: *mut UI, uis: *mut UI_STRING) -> c_int,
+    ui_flush: extern fn(ui: *mut UI) -> c_int,
+    ui_read_string: extern fn(ui: *mut UI, uis: *mut UI_STRING) -> c_int,
+    ui_close_session: extern fn(ui: *mut UI) -> c_int,
+    ui_construct_prompt: extern fn(ui: *mut UI, object_desc: *const c_char, object_name: *const c_char) -> *mut c_char,
+}
+
+const UI_FLAG_REDOABLE: c_int = 0x0001;
+const UI_FLAG_PRINT_ERRORS: c_int = 0x0100;
+
+#[repr(C)]
+pub struct UI {
+    meth: *const UI_METHOD,
+    strings: *mut c_void,
+    user_data: *mut c_void,
+    ex_data: CRYPTO_EX_DATA,
+    flags: c_int,
+}
+
+#[repr(C)]
+pub struct UI_STRING {
+    string_type: UI_string_types,
+    out_string: *const c_char,
+    input_flags: c_int,
+    result_buf: *mut c_char,
+}
+
+#[repr(C)]
+pub enum UI_string_types {
+    UIT_NONE=0,
+    UIT_PROMPT,     
+    UIT_VERIFY,     
+    UIT_BOOLEAN,       
+    UIT_INFO,  
+    UIT_ERROR,
+}
diff --git a/openssl-sys/src/lib.rs b/openssl-sys/src/lib.rs
index 9596a59b5b..0453c55e1f 100644
--- a/openssl-sys/src/lib.rs
+++ b/openssl-sys/src/lib.rs
@@ -29,6 +29,7 @@ pub use dtls1::*;
 pub use ec::*;
 pub use err::*;
 pub use evp::*;
+pub use engine::*;
 pub use hmac::*;
 pub use obj_mac::*;
 pub use object::*;
@@ -66,6 +67,7 @@ mod dtls1;
 mod ec;
 mod err;
 mod evp;
+mod engine;
 mod hmac;
 mod obj_mac;
 mod object;
diff --git a/openssl-sys/src/ssl.rs b/openssl-sys/src/ssl.rs
index f60b129bc7..1c7d9b43a8 100644
--- a/openssl-sys/src/ssl.rs
+++ b/openssl-sys/src/ssl.rs
@@ -1149,6 +1149,8 @@ extern "C" {
     #[cfg(not(libressl))]
     pub fn SSL_CTX_add_client_CA(ctx: *mut SSL_CTX, cacert: *mut X509) -> c_int;
 
+    pub fn SSL_CTX_set_client_cert_cb(ctx: *mut SSL_CTX, client_cert_cb: extern fn(ssl: *mut SSL, x509: *mut*mut X509, pkey: *mut*mut EVP_PKEY));
+
     pub fn SSL_CTX_set_default_verify_paths(ctx: *mut SSL_CTX) -> c_int;
     pub fn SSL_CTX_load_verify_locations(
         ctx: *mut SSL_CTX,