Officially deprecate headers

Create BOTAN_DEPRECATED_HEADER so we can warn about this consistently.

Shuffle around the filter headers so all of the concrete filters
are defined in filters.h instead of being spread across many headers.

Document which headers are deprecated as well as a list of headers which
will be made internal-only in a future major release.

32 files changed, 618 insertions, 694 deletions

diff --git a/doc/deprecated.rst b/doc/deprecated.rst
index 41f00d0d5..128a662bb 100644
--- a/doc/deprecated.rst
+++ b/doc/deprecated.rst
@@ -21,7 +21,19 @@ in the source.
 - Directly accessing the member variables of types calendar_point, ASN1_Attribute,
   AlgorithmIdentifier, and BER_Object
 
-- The headers ``botan.h``, ``init.h``, ``lookup.h``, ``threefish.h``, ``sm2_enc.h``
+- The following headers are currently public, but will be completely
+  removed in a future major release: ``botan.h``, ``init.h``,
+  ``lookup.h``, ``threefish.h``, ``sm2_enc.h``, ``datastor.h``,
+  ``basefilt.h``, ``hex_filt.h``, ``b64_filt.h``, ``comp_filter.h``,
+  ``key_filt.h``, ``buf_filt.h``, ``cipher_filter.h``
+
+- The following headers are currently public, but will be made
+  internal in a future major release, and no longer usable by
+  applications: ``rotate.h``, ``loadstor.h``, ``mul128.h``,
+  ``dyn_load.h``, ``atomic.h``, ``blinding.h``, ``gf2m_small_m.h``,
+  ``locking_allocator.h``, ``polyn_gf2m.h`,, ``parsing.h``,
+  ``rfc6979.h``, ``divide.h``, ``charset.h``, ``secqueue.h``,
+  ``buf_filt.h``, ``keypair.h``, ``http_util.h``, ``scan_name.h``
 
 - Using a default output length for "SHAKE-128" and "SHAKE-256". Instead,
   always specify the desired output length.
diff --git a/doc/dev_ref/mistakes.rst b/doc/dev_ref/mistakes.rst
index 9f89e3059..03b2c7905 100644
--- a/doc/dev_ref/mistakes.rst
+++ b/doc/dev_ref/mistakes.rst
@@ -27,6 +27,13 @@ the overall API and ABI surface.
 These interfaces are now deprecated, and perhaps will be able to be
 removed eventually.
 
+Header Directories
+-------------------
+
+It would have been better to install all headers as ``X/header.h``
+where ``X`` is the base dir in the source, eg ``block/aes128.h``,
+``hash/md5.h``, ...
+
 Exceptions
 -----------
 
diff --git a/src/build-data/version.txt b/src/build-data/version.txt
index 2dc302a20..ed6bafc01 100644
--- a/src/build-data/version.txt
+++ b/src/build-data/version.txt
@@ -2,7 +2,7 @@
 release_major = 2
 release_minor = 11
 release_patch = 0
-release_so_abi_rev = 10
+release_so_abi_rev = 11
 
 # These are set by the distribution script
 release_vc_rev = None
diff --git a/src/lib/base/botan.h b/src/lib/base/botan.h
index 26bfa75a7..a473e8fbf 100644
--- a/src/lib/base/botan.h
+++ b/src/lib/base/botan.h
@@ -16,12 +16,6 @@
 * This header file will be removed in Botan 3.x
 */
 
-#if defined(__GNUC__)
-  #warning "botan/botan.h is deprecated"
-#elif defined(_MSC_VER)
-  #pragma message ("botan/botan.h is deprecated")
-#endif
-
 #include <botan/lookup.h>
 #include <botan/version.h>
 #include <botan/parsing.h>
@@ -42,4 +36,6 @@
   #include <botan/pkcs8.h>
 #endif
 
+BOTAN_DEPRECATED_HEADER(botan.h)
+
 #endif
diff --git a/src/lib/base/init.h b/src/lib/base/init.h
index ba014d8e1..668650846 100644
--- a/src/lib/base/init.h
+++ b/src/lib/base/init.h
@@ -13,6 +13,8 @@
 
 namespace Botan {
 
+BOTAN_DEPRECATED_HEADER(init.h)
+
 /*
 * Previously botan had state whose lifetime had to be explicitly
 * managed by the application. As of 1.11.14 this is no longer the
diff --git a/src/lib/base/lookup.h b/src/lib/base/lookup.h
index 1cfa7d3c9..4a14230db 100644
--- a/src/lib/base/lookup.h
+++ b/src/lib/base/lookup.h
@@ -32,6 +32,8 @@
 
 namespace Botan {
 
+BOTAN_DEPRECATED_HEADER(lookup.h)
+
 /*
 * As of 1.11.26 this header is deprecated. Instead use the calls T::create and
 * T::providers (as demonstrated in the implementation below).
diff --git a/src/lib/block/threefish_512/threefish.h b/src/lib/block/threefish_512/threefish.h
index 6b21e9fdd..f866a717f 100644
--- a/src/lib/block/threefish_512/threefish.h
+++ b/src/lib/block/threefish_512/threefish.h
@@ -8,6 +8,10 @@
 #ifndef BOTAN_THREEFISH_H_
 #define BOTAN_THREEFISH_H_
 
+// This header is deprecated and will be removed in a future major release
+
 #include <botan/threefish_512.h>
 
+BOTAN_DEPRECATED_HEADER(threefish.h)
+
 #endif
diff --git a/src/lib/filters/aead_filt.h b/src/lib/filters/aead_filt.h
deleted file mode 100644
index f569423a6..000000000
--- a/src/lib/filters/aead_filt.h
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
-* Filter interface for AEAD Modes
-* (C) 2013 Jack Lloyd
-*
-* Botan is released under the Simplified BSD License (see license.txt)
-*/
-
-#ifndef BOTAN_AEAD_FILTER_H_
-#define BOTAN_AEAD_FILTER_H_
-
-#include <botan/cipher_filter.h>
-#include <botan/aead.h>
-
-namespace Botan {
-
-/**
-* Filter interface for AEAD Modes
-*/
-class AEAD_Filter final : public Cipher_Mode_Filter
-   {
-   public:
-      AEAD_Filter(AEAD_Mode* aead) : Cipher_Mode_Filter(aead) {}
-
-      /**
-      * Set associated data that is not included in the ciphertext but
-      * that should be authenticated. Must be called after set_key
-      * and before end_msg.
-      *
-      * @param ad the associated data
-      * @param ad_len length of add in bytes
-      */
-      void set_associated_data(const uint8_t ad[], size_t ad_len)
-         {
-         dynamic_cast<AEAD_Mode&>(get_transform()).set_associated_data(ad, ad_len);
-         }
-   };
-
-}
-
-#endif
diff --git a/src/lib/filters/codec_filt/b64_filt.cpp b/src/lib/filters/b64_filt.cpp
index 0ce158fb4..8cbba1a6e 100644
--- a/src/lib/filters/codec_filt/b64_filt.cpp
+++ b/src/lib/filters/b64_filt.cpp
@@ -5,7 +5,7 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/b64_filt.h>
+#include <botan/filters.h>
 #include <botan/base64.h>
 #include <botan/exceptn.h>
 #include <algorithm>
diff --git a/src/lib/filters/b64_filt.h b/src/lib/filters/b64_filt.h
new file mode 100644
index 000000000..af7bb7cf2
--- /dev/null
+++ b/src/lib/filters/b64_filt.h
@@ -0,0 +1,14 @@
+/*
+* Base64 Encoder/Decoder
+* (C) 1999-2010 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_BASE64_FILTER_H_
+#define BOTAN_BASE64_FILTER_H_
+
+#include <botan/filters.h>
+BOTAN_DEPRECATED_HEADER(b64_filt.h)
+
+#endif
diff --git a/src/lib/filters/basefilt.cpp b/src/lib/filters/basefilt.cpp
index 89026f600..b34b70bd6 100644
--- a/src/lib/filters/basefilt.cpp
+++ b/src/lib/filters/basefilt.cpp
@@ -1,21 +1,13 @@
 /*
-* Basic Filters
 * (C) 1999-2007 Jack Lloyd
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/basefilt.h>
-#include <botan/key_filt.h>
+#include <botan/filters.h>
 
 namespace Botan {
 
-void Keyed_Filter::set_iv(const InitializationVector& iv)
-   {
-   if(iv.length() != 0)
-      throw Invalid_IV_Length(name(), iv.length());
-   }
-
 /*
 * Chain Constructor
 */
@@ -40,11 +32,6 @@ Chain::Chain(Filter* filters[], size_t count)
          }
    }
 
-std::string Chain::name() const
-   {
-   return "Chain";
-   }
-
 /*
 * Fork Constructor
 */
@@ -62,9 +49,4 @@ Fork::Fork(Filter* filters[], size_t count)
    set_next(filters, count);
    }
 
-std::string Fork::name() const
-   {
-   return "Fork";
-   }
-
 }
diff --git a/src/lib/filters/basefilt.h b/src/lib/filters/basefilt.h
index 922d35669..422989b75 100644
--- a/src/lib/filters/basefilt.h
+++ b/src/lib/filters/basefilt.h
@@ -9,116 +9,10 @@
 #ifndef BOTAN_BASEFILT_H_
 #define BOTAN_BASEFILT_H_
 
-#include <botan/filter.h>
+// This header is deprecated and will be removed in a future major release
 
-#if defined(BOTAN_TARGET_OS_HAS_THREADS)
-  #include <thread>
-#endif
-
-namespace Botan {
-
-/**
-* BitBucket is a filter which simply discards all inputs
-*/
-class BOTAN_PUBLIC_API(2,0) BitBucket final : public Filter
-   {
-   public:
-      void write(const uint8_t[], size_t) override { /* discard */ }
-
-      std::string name() const override { return "BitBucket"; }
-   };
-
-/**
-* This class represents Filter chains. A Filter chain is an ordered
-* concatenation of Filters, the input to a Chain sequentially passes
-* through all the Filters contained in the Chain.
-*/
-
-class BOTAN_PUBLIC_API(2,0) Chain final : public Fanout_Filter
-   {
-   public:
-      void write(const uint8_t input[], size_t length) override { send(input, length); }
-
-      std::string name() const override;
-
-      /**
-      * Construct a chain of up to four filters. The filters are set
-      * up in the same order as the arguments.
-      */
-      Chain(Filter* = nullptr, Filter* = nullptr,
-            Filter* = nullptr, Filter* = nullptr);
-
-      /**
-      * Construct a chain from range of filters
-      * @param filter_arr the list of filters
-      * @param length how many filters
-      */
-      Chain(Filter* filter_arr[], size_t length);
-   };
-
-/**
-* This class represents a fork filter, whose purpose is to fork the
-* flow of data. It causes an input message to result in n messages at
-* the end of the filter, where n is the number of forks.
-*/
-class BOTAN_PUBLIC_API(2,0) Fork : public Fanout_Filter
-   {
-   public:
-      void write(const uint8_t input[], size_t length) override { send(input, length); }
-      void set_port(size_t n) { Fanout_Filter::set_port(n); }
-
-      std::string name() const override;
-
-      /**
-      * Construct a Fork filter with up to four forks.
-      */
-      Fork(Filter*, Filter*, Filter* = nullptr, Filter* = nullptr);
-
-      /**
-      * Construct a Fork from range of filters
-      * @param filter_arr the list of filters
-      * @param length how many filters
-      */
-      Fork(Filter* filter_arr[], size_t length);
-   };
-
-#if defined(BOTAN_HAS_THREAD_UTILS)
-
-/**
-* This class is a threaded version of the Fork filter. While this uses
-* threads, the class itself is NOT thread-safe. This is meant as a drop-
-* in replacement for Fork where performance gains are possible.
-*/
-class BOTAN_PUBLIC_API(2,0) Threaded_Fork final : public Fork
-   {
-   public:
-      std::string name() const override;
-
-      /**
-      * Construct a Threaded_Fork filter with up to four forks.
-      */
-      Threaded_Fork(Filter*, Filter*, Filter* = nullptr, Filter* = nullptr);
-
-      /**
-      * Construct a Threaded_Fork from range of filters
-      * @param filter_arr the list of filters
-      * @param length how many filters
-      */
-      Threaded_Fork(Filter* filter_arr[], size_t length);
-
-      ~Threaded_Fork();
-
-   private:
-      void set_next(Filter* f[], size_t n);
-      void send(const uint8_t in[], size_t length) override;
-      void thread_delegate_work(const uint8_t input[], size_t length);
-      void thread_entry(Filter* filter);
-
-      std::vector<std::shared_ptr<std::thread>> m_threads;
-      std::unique_ptr<struct Threaded_Fork_Data> m_thread_data;
-   };
-#endif
+#include <botan/filters.h>
 
-}
+BOTAN_DEPRECATED_HEADER(basefilt.h)
 
 #endif
diff --git a/src/lib/filters/buf_filt.cpp b/src/lib/filters/buf_filt.cpp
index 11ca9bbfe..0e34a56dd 100644
--- a/src/lib/filters/buf_filt.cpp
+++ b/src/lib/filters/buf_filt.cpp
@@ -5,7 +5,7 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/buf_filt.h>
+#include <botan/filters.h>
 #include <botan/mem_ops.h>
 #include <botan/internal/rounding.h>
 #include <botan/exceptn.h>
diff --git a/src/lib/filters/buf_filt.h b/src/lib/filters/buf_filt.h
index b4cd8e680..1f9ed3eff 100644
--- a/src/lib/filters/buf_filt.h
+++ b/src/lib/filters/buf_filt.h
@@ -8,86 +8,7 @@
 #ifndef BOTAN_BUFFERED_FILTER_H_
 #define BOTAN_BUFFERED_FILTER_H_
 
-#include <botan/secmem.h>
-
-namespace Botan {
-
-/**
-* Filter mixin that breaks input into blocks, useful for
-* cipher modes
-*/
-class BOTAN_PUBLIC_API(2,0) Buffered_Filter
-   {
-   public:
-      /**
-      * Write bytes into the buffered filter, which will them emit them
-      * in calls to buffered_block in the subclass
-      * @param in the input bytes
-      * @param length of in in bytes
-      */
-      void write(const uint8_t in[], size_t length);
-
-      template<typename Alloc>
-         void write(const std::vector<uint8_t, Alloc>& in, size_t length)
-         {
-         write(in.data(), length);
-         }
-
-      /**
-      * Finish a message, emitting to buffered_block and buffered_final
-      * Will throw an exception if less than final_minimum bytes were
-      * written into the filter.
-      */
-      void end_msg();
-
-      /**
-      * Initialize a Buffered_Filter
-      * @param block_size the function buffered_block will be called
-      *        with inputs which are a multiple of this size
-      * @param final_minimum the function buffered_final will be called
-      *        with at least this many bytes.
-      */
-      Buffered_Filter(size_t block_size, size_t final_minimum);
-
-      virtual ~Buffered_Filter() = default;
-   protected:
-      /**
-      * The block processor, implemented by subclasses
-      * @param input some input bytes
-      * @param length the size of input, guaranteed to be a multiple
-      *        of block_size
-      */
-      virtual void buffered_block(const uint8_t input[], size_t length) = 0;
-
-      /**
-      * The final block, implemented by subclasses
-      * @param input some input bytes
-      * @param length the size of input, guaranteed to be at least
-      *        final_minimum bytes
-      */
-      virtual void buffered_final(const uint8_t input[], size_t length) = 0;
-
-      /**
-      * @return block size of inputs
-      */
-      size_t buffered_block_size() const { return m_main_block_mod; }
-
-      /**
-      * @return current position in the buffer
-      */
-      size_t current_position() const { return m_buffer_pos; }
-
-      /**
-      * Reset the buffer position
-      */
-      void buffer_reset() { m_buffer_pos = 0; }
-   private:
-      size_t m_main_block_mod, m_final_minimum;
-
-      secure_vector<uint8_t> m_buffer;
-      size_t m_buffer_pos;
-   };
-
-}
+#include <botan/filters.h>
+BOTAN_DEPRECATED_HEADER(buf_filt.h)
 
 #endif
diff --git a/src/lib/filters/cipher_filter.cpp b/src/lib/filters/cipher_filter.cpp
index a3e7bd1c3..720aeac6f 100644
--- a/src/lib/filters/cipher_filter.cpp
+++ b/src/lib/filters/cipher_filter.cpp
@@ -5,7 +5,7 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/cipher_filter.h>
+#include <botan/filters.h>
 #include <botan/internal/rounding.h>
 
 namespace Botan {
diff --git a/src/lib/filters/cipher_filter.h b/src/lib/filters/cipher_filter.h
index 750385d15..84fc58b6e 100644
--- a/src/lib/filters/cipher_filter.h
+++ b/src/lib/filters/cipher_filter.h
@@ -5,54 +5,10 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#ifndef BOTAN_TRANSFORM_FILTER_H_
-#define BOTAN_TRANSFORM_FILTER_H_
+#ifndef BOTAN_CIPHER_FILTER_H_
+#define BOTAN_CIPHER_FILTER_H_
 
-#include <botan/cipher_mode.h>
-#include <botan/key_filt.h>
-#include <botan/buf_filt.h>
-
-namespace Botan {
-
-/**
-* Filter interface for cipher modes
-*/
-class BOTAN_PUBLIC_API(2,0) Cipher_Mode_Filter final : public Keyed_Filter,
-                                     private Buffered_Filter
-   {
-   public:
-      explicit Cipher_Mode_Filter(Cipher_Mode* t);
-
-      explicit Cipher_Mode_Filter(std::unique_ptr<Cipher_Mode> t) :
-         Cipher_Mode_Filter(t.release()) {}
-
-      void set_iv(const InitializationVector& iv) override;
-
-      void set_key(const SymmetricKey& key) override;
-
-      Key_Length_Specification key_spec() const override;
-
-      bool valid_iv_length(size_t length) const override;
-
-      std::string name() const override;
-
-   private:
-      void write(const uint8_t input[], size_t input_length) override;
-      void start_msg() override;
-      void end_msg() override;
-
-      void buffered_block(const uint8_t input[], size_t input_length) override;
-      void buffered_final(const uint8_t input[], size_t input_length) override;
-
-      std::unique_ptr<Cipher_Mode> m_mode;
-      std::vector<uint8_t> m_nonce;
-      secure_vector<uint8_t> m_buffer;
-   };
-
-// deprecated aliases, will be removed before 2.0
-typedef Cipher_Mode_Filter Transform_Filter;
-typedef Transform_Filter Transformation_Filter;
-
-}
+#include <botan/filters.h>
+BOTAN_DEPRECATED_HEADER(cipher_filter.h)
 
 #endif
diff --git a/src/lib/filters/codec_filt/b64_filt.h b/src/lib/filters/codec_filt/b64_filt.h
deleted file mode 100644
index 9c9602b98..000000000
--- a/src/lib/filters/codec_filt/b64_filt.h
+++ /dev/null
@@ -1,88 +0,0 @@
-/*
-* Base64 Encoder/Decoder
-* (C) 1999-2010 Jack Lloyd
-*
-* Botan is released under the Simplified BSD License (see license.txt)
-*/
-
-#ifndef BOTAN_BASE64_FILTER_H_
-#define BOTAN_BASE64_FILTER_H_
-
-#include <botan/filter.h>
-
-namespace Botan {
-
-/**
-* This class represents a Base64 encoder.
-*/
-class BOTAN_PUBLIC_API(2,0) Base64_Encoder final : public Filter
-   {
-   public:
-      std::string name() const override { return "Base64_Encoder"; }
-
-      /**
-      * Input a part of a message to the encoder.
-      * @param input the message to input as a byte array
-      * @param length the length of the byte array input
-      */
-      void write(const uint8_t input[], size_t length) override;
-
-      /**
-      * Inform the Encoder that the current message shall be closed.
-      */
-      void end_msg() override;
-
-      /**
-      * Create a base64 encoder.
-      * @param breaks whether to use line breaks in the output
-      * @param length the length of the lines of the output
-      * @param t_n whether to use a trailing newline
-      */
-      Base64_Encoder(bool breaks = false, size_t length = 72,
-                     bool t_n = false);
-   private:
-      void encode_and_send(const uint8_t input[], size_t length,
-                           bool final_inputs = false);
-      void do_output(const uint8_t output[], size_t length);
-
-      const size_t m_line_length;
-      const bool m_trailing_newline;
-      std::vector<uint8_t> m_in, m_out;
-      size_t m_position, m_out_position;
-   };
-
-/**
-* This object represents a Base64 decoder.
-*/
-class BOTAN_PUBLIC_API(2,0) Base64_Decoder final : public Filter
-   {
-   public:
-      std::string name() const override { return "Base64_Decoder"; }
-
-      /**
-      * Input a part of a message to the decoder.
-      * @param input the message to input as a byte array
-      * @param length the length of the byte array input
-      */
-      void write(const uint8_t input[], size_t length) override;
-
-      /**
-      * Finish up the current message
-      */
-      void end_msg() override;
-
-      /**
-      * Create a base64 decoder.
-      * @param checking the type of checking that shall be performed by
-      * the decoder
-      */
-      explicit Base64_Decoder(Decoder_Checking checking = NONE);
-   private:
-      const Decoder_Checking m_checking;
-      std::vector<uint8_t> m_in, m_out;
-      size_t m_position;
-   };
-
-}
-
-#endif
diff --git a/src/lib/filters/codec_filt/hex_filt.h b/src/lib/filters/codec_filt/hex_filt.h
deleted file mode 100644
index 4128d627a..000000000
--- a/src/lib/filters/codec_filt/hex_filt.h
+++ /dev/null
@@ -1,81 +0,0 @@
-/*
-* Hex Encoder/Decoder
-* (C) 1999-2010 Jack Lloyd
-*
-* Botan is released under the Simplified BSD License (see license.txt)
-*/
-
-#ifndef BOTAN_HEX_FILTER_H_
-#define BOTAN_HEX_FILTER_H_
-
-#include <botan/filter.h>
-
-namespace Botan {
-
-/**
-* Converts arbitrary binary data to hex strings, optionally with
-* newlines inserted
-*/
-class BOTAN_PUBLIC_API(2,0) Hex_Encoder final : public Filter
-   {
-   public:
-      /**
-      * Whether to use uppercase or lowercase letters for the encoded string.
-      */
-      enum Case { Uppercase, Lowercase };
-
-      std::string name() const override { return "Hex_Encoder"; }
-
-      void write(const uint8_t in[], size_t length) override;
-      void end_msg() override;
-
-      /**
-      * Create a hex encoder.
-      * @param the_case the case to use in the encoded strings.
-      */
-      explicit Hex_Encoder(Case the_case);
-
-      /**
-      * Create a hex encoder.
-      * @param newlines should newlines be used
-      * @param line_length if newlines are used, how long are lines
-      * @param the_case the case to use in the encoded strings
-      */
-      Hex_Encoder(bool newlines = false,
-                  size_t line_length = 72,
-                  Case the_case = Uppercase);
-   private:
-      void encode_and_send(const uint8_t[], size_t);
-
-      const Case m_casing;
-      const size_t m_line_length;
-      std::vector<uint8_t> m_in, m_out;
-      size_t m_position, m_counter;
-   };
-
-/**
-* Converts hex strings to bytes
-*/
-class BOTAN_PUBLIC_API(2,0) Hex_Decoder final : public Filter
-   {
-   public:
-      std::string name() const override { return "Hex_Decoder"; }
-
-      void write(const uint8_t[], size_t) override;
-      void end_msg() override;
-
-      /**
-      * Construct a Hex Decoder using the specified
-      * character checking.
-      * @param checking the checking to use during decoding.
-      */
-      explicit Hex_Decoder(Decoder_Checking checking = NONE);
-   private:
-      const Decoder_Checking m_checking;
-      std::vector<uint8_t> m_in, m_out;
-      size_t m_position;
-   };
-
-}
-
-#endif
diff --git a/src/lib/filters/codec_filt/info.txt b/src/lib/filters/codec_filt/info.txt
index 347c876a7..fd7b3fbd3 100644
--- a/src/lib/filters/codec_filt/info.txt
+++ b/src/lib/filters/codec_filt/info.txt
@@ -1,8 +1,6 @@
 <defines>
-CODEC_FILTERS -> 20131128
 </defines>
 
 <requires>
-base64
 filters
 </requires>
diff --git a/src/lib/filters/comp_filter.cpp b/src/lib/filters/comp_filter.cpp
index 2563a4907..c2814460a 100644
--- a/src/lib/filters/comp_filter.cpp
+++ b/src/lib/filters/comp_filter.cpp
@@ -6,7 +6,7 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/comp_filter.h>
+#include <botan/filters.h>
 #include <botan/exceptn.h>
 
 #if defined(BOTAN_HAS_COMPRESSION)
diff --git a/src/lib/filters/comp_filter.h b/src/lib/filters/comp_filter.h
index d9cc00b68..86b587ac3 100644
--- a/src/lib/filters/comp_filter.h
+++ b/src/lib/filters/comp_filter.h
@@ -8,64 +8,8 @@
 #ifndef BOTAN_COMPRESSION_FILTER_H_
 #define BOTAN_COMPRESSION_FILTER_H_
 
-#include <botan/filter.h>
+BOTAN_DEPRECATED_HEADER(comp_filter.h)
 
-namespace Botan {
-
-#if defined(BOTAN_HAS_COMPRESSION)
-
-class Compression_Algorithm;
-class Decompression_Algorithm;
-
-/**
-* Filter interface for compression
-*/
-class BOTAN_PUBLIC_API(2,0) Compression_Filter final : public Filter
-   {
-   public:
-      void start_msg() override;
-      void write(const uint8_t input[], size_t input_length) override;
-      void end_msg() override;
-
-      void flush();
-
-      std::string name() const override;
-
-      Compression_Filter(const std::string& type,
-                         size_t compression_level,
-                         size_t buffer_size = 4096);
-
-      ~Compression_Filter();
-   private:
-      std::unique_ptr<Compression_Algorithm> m_comp;
-      size_t m_buffersize, m_level;
-      secure_vector<uint8_t> m_buffer;
-   };
-
-/**
-* Filter interface for decompression
-*/
-class BOTAN_PUBLIC_API(2,0) Decompression_Filter final : public Filter
-   {
-   public:
-      void start_msg() override;
-      void write(const uint8_t input[], size_t input_length) override;
-      void end_msg() override;
-
-      std::string name() const override;
-
-      Decompression_Filter(const std::string& type,
-                           size_t buffer_size = 4096);
-
-      ~Decompression_Filter();
-   private:
-      std::unique_ptr<Decompression_Algorithm> m_comp;
-      std::size_t m_buffersize;
-      secure_vector<uint8_t> m_buffer;
-   };
-
-#endif
-
-}
+#include <botan/filters.h>
 
 #endif
diff --git a/src/lib/filters/filters.h b/src/lib/filters/filters.h
index b4aee1207..c19e1a749 100644
--- a/src/lib/filters/filters.h
+++ b/src/lib/filters/filters.h
@@ -1,6 +1,7 @@
 /*
-* Filters
+* Common Filters
 * (C) 1999-2007,2015 Jack Lloyd
+* (C) 2013 Joel Low
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -8,10 +9,15 @@
 #ifndef BOTAN_FILTERS_H_
 #define BOTAN_FILTERS_H_
 
-#include <botan/basefilt.h>
-#include <botan/key_filt.h>
+#include <botan/secmem.h>
 #include <botan/data_snk.h>
 #include <botan/pipe.h>
+#include <botan/symkey.h>
+#include <botan/cipher_mode.h>
+
+#if defined(BOTAN_TARGET_OS_HAS_THREADS)
+  #include <thread>
+#endif
 
 #if defined(BOTAN_HAS_STREAM_CIPHER)
    #include <botan/stream_cipher.h>
@@ -25,13 +31,230 @@
    #include <botan/mac.h>
 #endif
 
-#if defined(BOTAN_HAS_CODEC_FILTERS)
-  #include <botan/b64_filt.h>
-  #include <botan/hex_filt.h>
-#endif
-
 namespace Botan {
 
+/**
+* Filter mixin that breaks input into blocks, useful for
+* cipher modes
+*/
+class BOTAN_PUBLIC_API(2,0) Buffered_Filter
+   {
+   public:
+      /**
+      * Write bytes into the buffered filter, which will them emit them
+      * in calls to buffered_block in the subclass
+      * @param in the input bytes
+      * @param length of in in bytes
+      */
+      void write(const uint8_t in[], size_t length);
+
+      template<typename Alloc>
+         void write(const std::vector<uint8_t, Alloc>& in, size_t length)
+         {
+         write(in.data(), length);
+         }
+
+      /**
+      * Finish a message, emitting to buffered_block and buffered_final
+      * Will throw an exception if less than final_minimum bytes were
+      * written into the filter.
+      */
+      void end_msg();
+
+      /**
+      * Initialize a Buffered_Filter
+      * @param block_size the function buffered_block will be called
+      *        with inputs which are a multiple of this size
+      * @param final_minimum the function buffered_final will be called
+      *        with at least this many bytes.
+      */
+      Buffered_Filter(size_t block_size, size_t final_minimum);
+
+      virtual ~Buffered_Filter() = default;
+   protected:
+      /**
+      * The block processor, implemented by subclasses
+      * @param input some input bytes
+      * @param length the size of input, guaranteed to be a multiple
+      *        of block_size
+      */
+      virtual void buffered_block(const uint8_t input[], size_t length) = 0;
+
+      /**
+      * The final block, implemented by subclasses
+      * @param input some input bytes
+      * @param length the size of input, guaranteed to be at least
+      *        final_minimum bytes
+      */
+      virtual void buffered_final(const uint8_t input[], size_t length) = 0;
+
+      /**
+      * @return block size of inputs
+      */
+      size_t buffered_block_size() const { return m_main_block_mod; }
+
+      /**
+      * @return current position in the buffer
+      */
+      size_t current_position() const { return m_buffer_pos; }
+
+      /**
+      * Reset the buffer position
+      */
+      void buffer_reset() { m_buffer_pos = 0; }
+   private:
+      size_t m_main_block_mod, m_final_minimum;
+
+      secure_vector<uint8_t> m_buffer;
+      size_t m_buffer_pos;
+   };
+
+/**
+* This class represents keyed filters, i.e. filters that have to be
+* fed with a key in order to function.
+*/
+class BOTAN_PUBLIC_API(2,0) Keyed_Filter : public Filter
+   {
+   public:
+      /**
+      * Set the key of this filter
+      * @param key the key to use
+      */
+      virtual void set_key(const SymmetricKey& key) = 0;
+
+      /**
+      * Set the initialization vector of this filter. Note: you should
+      * call set_iv() only after you have called set_key()
+      * @param iv the initialization vector to use
+      */
+      virtual void set_iv(const InitializationVector& iv)
+         {
+         if(iv.length() != 0)
+            throw Invalid_IV_Length(name(), iv.length());
+         }
+
+      /**
+      * Check whether a key length is valid for this filter
+      * @param length the key length to be checked for validity
+      * @return true if the key length is valid, false otherwise
+      */
+      bool valid_keylength(size_t length) const
+         {
+         return key_spec().valid_keylength(length);
+         }
+
+      /**
+      * @return object describing limits on key size
+      */
+      virtual Key_Length_Specification key_spec() const = 0;
+
+      /**
+      * Check whether an IV length is valid for this filter
+      * @param length the IV length to be checked for validity
+      * @return true if the IV length is valid, false otherwise
+      */
+      virtual bool valid_iv_length(size_t length) const
+         { return (length == 0); }
+   };
+
+/**
+* Filter interface for cipher modes
+*/
+class BOTAN_PUBLIC_API(2,0) Cipher_Mode_Filter final : public Keyed_Filter,
+                                     private Buffered_Filter
+   {
+   public:
+      explicit Cipher_Mode_Filter(Cipher_Mode* t);
+
+      explicit Cipher_Mode_Filter(std::unique_ptr<Cipher_Mode> t) :
+         Cipher_Mode_Filter(t.release()) {}
+
+      void set_iv(const InitializationVector& iv) override;
+
+      void set_key(const SymmetricKey& key) override;
+
+      Key_Length_Specification key_spec() const override;
+
+      bool valid_iv_length(size_t length) const override;
+
+      std::string name() const override;
+
+   private:
+      void write(const uint8_t input[], size_t input_length) override;
+      void start_msg() override;
+      void end_msg() override;
+
+      void buffered_block(const uint8_t input[], size_t input_length) override;
+      void buffered_final(const uint8_t input[], size_t input_length) override;
+
+      std::unique_ptr<Cipher_Mode> m_mode;
+      std::vector<uint8_t> m_nonce;
+      secure_vector<uint8_t> m_buffer;
+   };
+
+// deprecated aliases, will be removed in a future major release
+typedef Cipher_Mode_Filter Transform_Filter;
+typedef Transform_Filter Transformation_Filter;
+
+/*
+* Get a cipher object
+*/
+
+/**
+* Factory method for general symmetric cipher filters. No key will be
+* set in the filter.
+*
+* @param algo_spec the name of the desired cipher
+* @param direction determines whether the filter will be an encrypting or
+* decrypting filter
+* @return pointer to the encryption or decryption filter
+*/
+inline Keyed_Filter* get_cipher(const std::string& algo_spec,
+                                Cipher_Dir direction)
+   {
+   std::unique_ptr<Cipher_Mode> c(Cipher_Mode::create_or_throw(algo_spec, direction));
+   return new Cipher_Mode_Filter(c.release());
+   }
+
+/**
+* Factory method for general symmetric cipher filters.
+* @param algo_spec the name of the desired cipher
+* @param key the key to be used for encryption/decryption performed by
+* the filter
+* @param direction determines whether the filter will be an encrypting
+* or decrypting filter
+* @return pointer to the encryption or decryption filter
+*/
+inline Keyed_Filter* get_cipher(const std::string& algo_spec,
+                                const SymmetricKey& key,
+                                Cipher_Dir direction)
+   {
+   Keyed_Filter* cipher = get_cipher(algo_spec, direction);
+   cipher->set_key(key);
+   return cipher;
+   }
+
+/**
+* Factory method for general symmetric cipher filters.
+* @param algo_spec the name of the desired cipher
+* @param key the key to be used for encryption/decryption performed by
+* the filter
+* @param iv the initialization vector to be used
+* @param direction determines whether the filter will be an encrypting
+* or decrypting filter
+* @return pointer to newly allocated encryption or decryption filter
+*/
+inline Keyed_Filter* get_cipher(const std::string& algo_spec,
+                                const SymmetricKey& key,
+                                const InitializationVector& iv,
+                                Cipher_Dir direction)
+   {
+   Keyed_Filter* cipher = get_cipher(algo_spec, key, direction);
+   if(iv.length())
+      cipher->set_iv(iv);
+   return cipher;
+   }
+
 #if defined(BOTAN_HAS_STREAM_CIPHER)
 
 /**
@@ -222,6 +445,297 @@ class BOTAN_PUBLIC_API(2,0) MAC_Filter final : public Keyed_Filter
    };
 #endif
 
+#if defined(BOTAN_HAS_COMPRESSION)
+
+class Compression_Algorithm;
+class Decompression_Algorithm;
+
+/**
+* Filter interface for compression
+*/
+class BOTAN_PUBLIC_API(2,0) Compression_Filter final : public Filter
+   {
+   public:
+      void start_msg() override;
+      void write(const uint8_t input[], size_t input_length) override;
+      void end_msg() override;
+
+      void flush();
+
+      std::string name() const override;
+
+      Compression_Filter(const std::string& type,
+                         size_t compression_level,
+                         size_t buffer_size = 4096);
+
+      ~Compression_Filter();
+   private:
+      std::unique_ptr<Compression_Algorithm> m_comp;
+      size_t m_buffersize, m_level;
+      secure_vector<uint8_t> m_buffer;
+   };
+
+/**
+* Filter interface for decompression
+*/
+class BOTAN_PUBLIC_API(2,0) Decompression_Filter final : public Filter
+   {
+   public:
+      void start_msg() override;
+      void write(const uint8_t input[], size_t input_length) override;
+      void end_msg() override;
+
+      std::string name() const override;
+
+      Decompression_Filter(const std::string& type,
+                           size_t buffer_size = 4096);
+
+      ~Decompression_Filter();
+   private:
+      std::unique_ptr<Decompression_Algorithm> m_comp;
+      std::size_t m_buffersize;
+      secure_vector<uint8_t> m_buffer;
+   };
+
+#endif
+
+/**
+* This class represents a Base64 encoder.
+*/
+class BOTAN_PUBLIC_API(2,0) Base64_Encoder final : public Filter
+   {
+   public:
+      std::string name() const override { return "Base64_Encoder"; }
+
+      /**
+      * Input a part of a message to the encoder.
+      * @param input the message to input as a byte array
+      * @param length the length of the byte array input
+      */
+      void write(const uint8_t input[], size_t length) override;
+
+      /**
+      * Inform the Encoder that the current message shall be closed.
+      */
+      void end_msg() override;
+
+      /**
+      * Create a base64 encoder.
+      * @param breaks whether to use line breaks in the output
+      * @param length the length of the lines of the output
+      * @param t_n whether to use a trailing newline
+      */
+      Base64_Encoder(bool breaks = false, size_t length = 72,
+                     bool t_n = false);
+   private:
+      void encode_and_send(const uint8_t input[], size_t length,
+                           bool final_inputs = false);
+      void do_output(const uint8_t output[], size_t length);
+
+      const size_t m_line_length;
+      const bool m_trailing_newline;
+      std::vector<uint8_t> m_in, m_out;
+      size_t m_position, m_out_position;
+   };
+
+/**
+* This object represents a Base64 decoder.
+*/
+class BOTAN_PUBLIC_API(2,0) Base64_Decoder final : public Filter
+   {
+   public:
+      std::string name() const override { return "Base64_Decoder"; }
+
+      /**
+      * Input a part of a message to the decoder.
+      * @param input the message to input as a byte array
+      * @param length the length of the byte array input
+      */
+      void write(const uint8_t input[], size_t length) override;
+
+      /**
+      * Finish up the current message
+      */
+      void end_msg() override;
+
+      /**
+      * Create a base64 decoder.
+      * @param checking the type of checking that shall be performed by
+      * the decoder
+      */
+      explicit Base64_Decoder(Decoder_Checking checking = NONE);
+   private:
+      const Decoder_Checking m_checking;
+      std::vector<uint8_t> m_in, m_out;
+      size_t m_position;
+   };
+
+/**
+* Converts arbitrary binary data to hex strings, optionally with
+* newlines inserted
+*/
+class BOTAN_PUBLIC_API(2,0) Hex_Encoder final : public Filter
+   {
+   public:
+      /**
+      * Whether to use uppercase or lowercase letters for the encoded string.
+      */
+      enum Case { Uppercase, Lowercase };
+
+      std::string name() const override { return "Hex_Encoder"; }
+
+      void write(const uint8_t in[], size_t length) override;
+      void end_msg() override;
+
+      /**
+      * Create a hex encoder.
+      * @param the_case the case to use in the encoded strings.
+      */
+      explicit Hex_Encoder(Case the_case);
+
+      /**
+      * Create a hex encoder.
+      * @param newlines should newlines be used
+      * @param line_length if newlines are used, how long are lines
+      * @param the_case the case to use in the encoded strings
+      */
+      Hex_Encoder(bool newlines = false,
+                  size_t line_length = 72,
+                  Case the_case = Uppercase);
+   private:
+      void encode_and_send(const uint8_t[], size_t);
+
+      const Case m_casing;
+      const size_t m_line_length;
+      std::vector<uint8_t> m_in, m_out;
+      size_t m_position, m_counter;
+   };
+
+/**
+* Converts hex strings to bytes
+*/
+class BOTAN_PUBLIC_API(2,0) Hex_Decoder final : public Filter
+   {
+   public:
+      std::string name() const override { return "Hex_Decoder"; }
+
+      void write(const uint8_t[], size_t) override;
+      void end_msg() override;
+
+      /**
+      * Construct a Hex Decoder using the specified
+      * character checking.
+      * @param checking the checking to use during decoding.
+      */
+      explicit Hex_Decoder(Decoder_Checking checking = NONE);
+   private:
+      const Decoder_Checking m_checking;
+      std::vector<uint8_t> m_in, m_out;
+      size_t m_position;
+   };
+
+/**
+* BitBucket is a filter which simply discards all inputs
+*/
+class BOTAN_PUBLIC_API(2,0) BitBucket final : public Filter
+   {
+   public:
+      void write(const uint8_t[], size_t) override { /* discard */ }
+
+      std::string name() const override { return "BitBucket"; }
+   };
+
+/**
+* This class represents Filter chains. A Filter chain is an ordered
+* concatenation of Filters, the input to a Chain sequentially passes
+* through all the Filters contained in the Chain.
+*/
+
+class BOTAN_PUBLIC_API(2,0) Chain final : public Fanout_Filter
+   {
+   public:
+      void write(const uint8_t input[], size_t length) override { send(input, length); }
+
+      std::string name() const override { return "Chain"; }
+
+      /**
+      * Construct a chain of up to four filters. The filters are set
+      * up in the same order as the arguments.
+      */
+      Chain(Filter* = nullptr, Filter* = nullptr,
+            Filter* = nullptr, Filter* = nullptr);
+
+      /**
+      * Construct a chain from range of filters
+      * @param filter_arr the list of filters
+      * @param length how many filters
+      */
+      Chain(Filter* filter_arr[], size_t length);
+   };
+
+/**
+* This class represents a fork filter, whose purpose is to fork the
+* flow of data. It causes an input message to result in n messages at
+* the end of the filter, where n is the number of forks.
+*/
+class BOTAN_PUBLIC_API(2,0) Fork : public Fanout_Filter
+   {
+   public:
+      void write(const uint8_t input[], size_t length) override { send(input, length); }
+      void set_port(size_t n) { Fanout_Filter::set_port(n); }
+
+      std::string name() const override { return "Fork"; }
+
+      /**
+      * Construct a Fork filter with up to four forks.
+      */
+      Fork(Filter*, Filter*, Filter* = nullptr, Filter* = nullptr);
+
+      /**
+      * Construct a Fork from range of filters
+      * @param filter_arr the list of filters
+      * @param length how many filters
+      */
+      Fork(Filter* filter_arr[], size_t length);
+   };
+
+#if defined(BOTAN_HAS_THREAD_UTILS)
+
+/**
+* This class is a threaded version of the Fork filter. While this uses
+* threads, the class itself is NOT thread-safe. This is meant as a drop-
+* in replacement for Fork where performance gains are possible.
+*/
+class BOTAN_PUBLIC_API(2,0) Threaded_Fork final : public Fork
+   {
+   public:
+      std::string name() const override;
+
+      /**
+      * Construct a Threaded_Fork filter with up to four forks.
+      */
+      Threaded_Fork(Filter*, Filter*, Filter* = nullptr, Filter* = nullptr);
+
+      /**
+      * Construct a Threaded_Fork from range of filters
+      * @param filter_arr the list of filters
+      * @param length how many filters
+      */
+      Threaded_Fork(Filter* filter_arr[], size_t length);
+
+      ~Threaded_Fork();
+
+   private:
+      void set_next(Filter* f[], size_t n);
+      void send(const uint8_t in[], size_t length) override;
+      void thread_delegate_work(const uint8_t input[], size_t length);
+      void thread_entry(Filter* filter);
+
+      std::vector<std::shared_ptr<std::thread>> m_threads;
+      std::unique_ptr<struct Threaded_Fork_Data> m_thread_data;
+   };
+#endif
+
 }
 
 #endif
diff --git a/src/lib/filters/codec_filt/hex_filt.cpp b/src/lib/filters/hex_filt.cpp
index be1dbbc5c..761c73ade 100644
--- a/src/lib/filters/codec_filt/hex_filt.cpp
+++ b/src/lib/filters/hex_filt.cpp
@@ -5,7 +5,7 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/hex_filt.h>
+#include <botan/filters.h>
 #include <botan/hex.h>
 #include <botan/exceptn.h>
 #include <algorithm>
diff --git a/src/lib/filters/hex_filt.h b/src/lib/filters/hex_filt.h
new file mode 100644
index 000000000..b529b5299
--- /dev/null
+++ b/src/lib/filters/hex_filt.h
@@ -0,0 +1,14 @@
+/*
+* Hex Encoder/Decoder
+* (C) 1999-2010 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_HEX_FILTER_H_
+#define BOTAN_HEX_FILTER_H_
+
+#include <botan/filters.h>
+BOTAN_DEPRECATED_HEADER(hex_filt.h)
+
+#endif
diff --git a/src/lib/filters/info.txt b/src/lib/filters/info.txt
index cfc114353..9fb8ef7ce 100644
--- a/src/lib/filters/info.txt
+++ b/src/lib/filters/info.txt
@@ -1,18 +1,21 @@
 <defines>
 FILTERS -> 20160415
+CODEC_FILTERS -> 20131128
 </defines>
 
 <header:public>
 basefilt.h
+comp_filter.h
+cipher_filter.h
 buf_filt.h
+key_filt.h
+
+secqueue.h
+
 data_snk.h
-comp_filter.h
 filter.h
 filters.h
-key_filt.h
 pipe.h
-secqueue.h
-cipher_filter.h
 </header:public>
 
 <header:internal>
@@ -21,4 +24,5 @@ out_buf.h
 
 <requires>
 modes
+base64
 </requires>
diff --git a/src/lib/filters/key_filt.cpp b/src/lib/filters/key_filt.cpp
deleted file mode 100644
index b87a8c87f..000000000
--- a/src/lib/filters/key_filt.cpp
+++ /dev/null
@@ -1,39 +0,0 @@
-/*
-* (C) 2015 Jack Lloyd
-*
-* Botan is released under the Simplified BSD License (see license.txt)
-*/
-
-#include <botan/key_filt.h>
-#include <botan/cipher_filter.h>
-
-namespace Botan {
-
-Keyed_Filter* get_cipher(const std::string& algo_spec,
-                         Cipher_Dir direction)
-   {
-   std::unique_ptr<Cipher_Mode> c(Cipher_Mode::create_or_throw(algo_spec, direction));
-   return new Cipher_Mode_Filter(c.release());
-   }
-
-Keyed_Filter* get_cipher(const std::string& algo_spec,
-                         const SymmetricKey& key,
-                         const InitializationVector& iv,
-                         Cipher_Dir direction)
-   {
-   Keyed_Filter* cipher = get_cipher(algo_spec, key, direction);
-   if(iv.length())
-      cipher->set_iv(iv);
-   return cipher;
-   }
-
-Keyed_Filter* get_cipher(const std::string& algo_spec,
-                         const SymmetricKey& key,
-                         Cipher_Dir direction)
-   {
-   Keyed_Filter* cipher = get_cipher(algo_spec, direction);
-   cipher->set_key(key);
-   return cipher;
-   }
-
-}
diff --git a/src/lib/filters/key_filt.h b/src/lib/filters/key_filt.h
index 67b689f99..3d85d886a 100644
--- a/src/lib/filters/key_filt.h
+++ b/src/lib/filters/key_filt.h
@@ -8,102 +8,7 @@
 #ifndef BOTAN_KEYED_FILTER_H_
 #define BOTAN_KEYED_FILTER_H_
 
-#include <botan/symkey.h>
 #include <botan/filter.h>
-#include <botan/cipher_mode.h>
-
-namespace Botan {
-
-/**
-* This class represents keyed filters, i.e. filters that have to be
-* fed with a key in order to function.
-*/
-class BOTAN_PUBLIC_API(2,0) Keyed_Filter : public Filter
-   {
-   public:
-      /**
-      * Set the key of this filter
-      * @param key the key to use
-      */
-      virtual void set_key(const SymmetricKey& key) = 0;
-
-      /**
-      * Set the initialization vector of this filter. Note: you should
-      * call set_iv() only after you have called set_key()
-      * @param iv the initialization vector to use
-      */
-      virtual void set_iv(const InitializationVector& iv);
-
-      /**
-      * Check whether a key length is valid for this filter
-      * @param length the key length to be checked for validity
-      * @return true if the key length is valid, false otherwise
-      */
-      bool valid_keylength(size_t length) const
-         {
-         return key_spec().valid_keylength(length);
-         }
-
-      /**
-      * @return object describing limits on key size
-      */
-      virtual Key_Length_Specification key_spec() const = 0;
-
-      /**
-      * Check whether an IV length is valid for this filter
-      * @param length the IV length to be checked for validity
-      * @return true if the IV length is valid, false otherwise
-      */
-      virtual bool valid_iv_length(size_t length) const
-         { return (length == 0); }
-   };
-
-
-
-/*
-* Get a cipher object
-*/
-
-/**
-* Factory method for general symmetric cipher filters.
-* @param algo_spec the name of the desired cipher
-* @param key the key to be used for encryption/decryption performed by
-* the filter
-* @param iv the initialization vector to be used
-* @param direction determines whether the filter will be an encrypting
-* or decrypting filter
-* @return pointer to newly allocated encryption or decryption filter
-*/
-BOTAN_PUBLIC_API(2,0) Keyed_Filter* get_cipher(const std::string& algo_spec,
-                                   const SymmetricKey& key,
-                                   const InitializationVector& iv,
-                                   Cipher_Dir direction);
-
-/**
-* Factory method for general symmetric cipher filters.
-* @param algo_spec the name of the desired cipher
-* @param key the key to be used for encryption/decryption performed by
-* the filter
-* @param direction determines whether the filter will be an encrypting
-* or decrypting filter
-* @return pointer to the encryption or decryption filter
-*/
-BOTAN_PUBLIC_API(2,0) Keyed_Filter* get_cipher(const std::string& algo_spec,
-                                   const SymmetricKey& key,
-                                   Cipher_Dir direction);
-
-/**
-* Factory method for general symmetric cipher filters. No key will be
-* set in the filter.
-*
-* @param algo_spec the name of the desired cipher
-* @param direction determines whether the filter will be an encrypting or
-* decrypting filter
-* @return pointer to the encryption or decryption filter
-*/
-BOTAN_PUBLIC_API(2,0) Keyed_Filter* get_cipher(const std::string& algo_spec,
-                                   Cipher_Dir direction);
-
-}
+BOTAN_DEPRECATED_HEADER(key_filt.h)
 
 #endif
diff --git a/src/lib/filters/threaded_fork.cpp b/src/lib/filters/threaded_fork.cpp
index 35ea94109..2d77f9fd1 100644
--- a/src/lib/filters/threaded_fork.cpp
+++ b/src/lib/filters/threaded_fork.cpp
@@ -6,7 +6,7 @@
 * Botan is released under the Simplified BSD License (see license.txt)
 */
 
-#include <botan/basefilt.h>
+#include <botan/filters.h>
 
 #if defined(BOTAN_HAS_THREAD_UTILS)
 
diff --git a/src/lib/math/bigint/bigint.h b/src/lib/math/bigint/bigint.h
index e6b7bc4bb..80b23ca8c 100644
--- a/src/lib/math/bigint/bigint.h
+++ b/src/lib/math/bigint/bigint.h
@@ -905,7 +905,7 @@ class BOTAN_PUBLIC_API(2,0) BigInt final
      * All elements of vec must have the same size, and output must be
      * pre-allocated with the same size.
      */
-     static void const_time_lookup(
+     static void BOTAN_DEPRECATED("No longer in use") const_time_lookup(
         secure_vector<word>& output,
         const std::vector<BigInt>& vec,
         size_t idx);
diff --git a/src/lib/pubkey/sm2/sm2_enc.h b/src/lib/pubkey/sm2/sm2_enc.h
index 1384d3726..ea8c43d9d 100644
--- a/src/lib/pubkey/sm2/sm2_enc.h
+++ b/src/lib/pubkey/sm2/sm2_enc.h
@@ -10,4 +10,6 @@
 
 #include <botan/sm2.h>
 
+BOTAN_DEPRECATED_HEADER(sm2_enc.h)
+
 #endif
diff --git a/src/lib/utils/compiler.h b/src/lib/utils/compiler.h
index c515e0507..abb2a79f0 100644
--- a/src/lib/utils/compiler.h
+++ b/src/lib/utils/compiler.h
@@ -100,13 +100,16 @@
 
   #if defined(__clang__)
     #define BOTAN_DEPRECATED(msg) __attribute__ ((deprecated))
+    #define BOTAN_DEPRECATED_HEADER(hdr) _Pragma("message \"this header is deprecated\"")
 
   #elif defined(_MSC_VER)
     #define BOTAN_DEPRECATED(msg) __declspec(deprecated(msg))
+    #define BOTAN_DEPRECATED_HEADER(hdr) __pragma("message \"this header is deprecated\"")
 
   #elif defined(__GNUG__)
     /* msg supported since GCC 4.5, earliest we support is 4.8 */
     #define BOTAN_DEPRECATED(msg) __attribute__ ((deprecated(msg)))
+    #define BOTAN_DEPRECATED_HEADER(hdr) _Pragma("GCC warning \"this header is deprecated\"")
   #endif
 
 #endif
@@ -115,6 +118,10 @@
   #define BOTAN_DEPRECATED(msg)
 #endif
 
+#if !defined(BOTAN_DEPRECATED_HEADER)
+  #define BOTAN_DEPRECATED_HEADER(hdr)
+#endif
+
 /*
 * Define BOTAN_NORETURN
 */
diff --git a/src/tests/test_filters.cpp b/src/tests/test_filters.cpp
index 33649e56a..e99329327 100644
--- a/src/tests/test_filters.cpp
+++ b/src/tests/test_filters.cpp
@@ -16,15 +16,9 @@
    #include <botan/pipe.h>
    #include <botan/filters.h>
    #include <botan/data_snk.h>
-   #include <botan/comp_filter.h>
    #include <botan/cipher_filter.h>
 #endif
 
-#if defined(BOTAN_HAS_CODEC_FILTERS)
-   #include <botan/hex_filt.h>
-   #include <botan/b64_filt.h>
-#endif
-
 #if defined(BOTAN_HAS_PIPE_UNIXFD_IO)
    #include <botan/fd_unix.h>
    #include <unistd.h>