diff --git a/openssl/src/cipher_ctx.rs b/openssl/src/cipher_ctx.rs
index 1769ee9716..58e789b044 100644
--- a/openssl/src/cipher_ctx.rs
+++ b/openssl/src/cipher_ctx.rs
@@ -581,7 +581,8 @@ impl CipherCtxRef {
     /// output size check removed. It can be used when the exact
     /// buffer size control is maintained by the caller.
     ///
-    /// SAFETY: The caller is expected to provide `output` buffer
+    /// # Safety
+    /// The caller is expected to provide `output` buffer
     /// large enough to contain correct number of bytes. For streaming
     /// ciphers the output buffer size should be at least as big as
     /// the input buffer. For block ciphers the size of the output
@@ -693,7 +694,8 @@ impl CipherCtxRef {
     /// This function is the same as [`Self::cipher_final`] but with
     /// the output buffer size check removed.
     ///
-    /// SAFETY: The caller is expected to provide `output` buffer
+    /// # Safety
+    /// The caller is expected to provide `output` buffer
     /// large enough to contain correct number of bytes. For streaming
     /// ciphers the output buffer can be empty, for block ciphers the
     /// output buffer should be at least as big as the block.
diff --git a/openssl/src/lib.rs b/openssl/src/lib.rs
index 4b9ee80454..5c9ccf7a05 100644
--- a/openssl/src/lib.rs
+++ b/openssl/src/lib.rs
@@ -119,7 +119,7 @@
 //! ```
 #![doc(html_root_url = "https://docs.rs/openssl/0.10")]
 #![warn(rust_2018_idioms)]
-#![allow(clippy::uninlined_format_args)]
+#![allow(clippy::uninlined_format_args, clippy::needless_doctest_main)]
 
 #[doc(inline)]
 pub use ffi::init;
diff --git a/openssl/src/symm.rs b/openssl/src/symm.rs
index 1e9dc34fc6..0ff9d874e2 100644
--- a/openssl/src/symm.rs
+++ b/openssl/src/symm.rs
@@ -696,6 +696,27 @@ impl Crypter {
         self.ctx.cipher_update(input, Some(output))
     }
 
+    /// Feeds data from `input` through the cipher, writing encrypted/decrypted
+    /// bytes into `output`.
+    ///
+    /// The number of bytes written to `output` is returned. Note that this may
+    /// not be equal to the length of `input`.
+    ///
+    /// # Safety
+    ///
+    /// The caller must provide an `output` buffer large enough to contain
+    /// correct number of bytes. For streaming ciphers the output buffer size
+    /// should be at least as big as the input buffer. For block ciphers the
+    /// size of the output buffer depends on the state of partially updated
+    /// blocks.
+    pub unsafe fn update_unchecked(
+        &mut self,
+        input: &[u8],
+        output: &mut [u8],
+    ) -> Result<usize, ErrorStack> {
+        self.ctx.cipher_update_unchecked(input, Some(output))
+    }
+
     /// Finishes the encryption/decryption process, writing any remaining data
     /// to `output`.
     ///