1 files changed, 90 insertions, 0 deletions
diff --git a/src/lib/modes/aead/chacha20poly1305/chacha20poly1305.h b/src/lib/modes/aead/chacha20poly1305/chacha20poly1305.h
new file mode 100644
index 000000000..de4560be7
--- /dev/null
+++ b/src/lib/modes/aead/chacha20poly1305/chacha20poly1305.h
@@ -0,0 +1,90 @@
+/*
+* ChaCha20Poly1305 AEAD
+* (C) 2014 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_CHACHA20_POLY1305_H__
+#define BOTAN_AEAD_CHACHA20_POLY1305_H__
+
+#include <botan/aead.h>
+#include <botan/stream_cipher.h>
+#include <botan/mac.h>
+
+namespace Botan {
+
+/**
+* Base class
+* See draft-irtf-cfrg-chacha20-poly1305-03 for specification
+*/
+class BOTAN_DLL ChaCha20Poly1305_Mode : public AEAD_Mode
+   {
+   public:
+      void set_associated_data(const byte ad[], size_t ad_len) override;
+
+      std::string name() const override { return "ChaCha20Poly1305"; }
+
+      size_t update_granularity() const override { return 64; }
+
+      Key_Length_Specification key_spec() const override
+         { return Key_Length_Specification(32); }
+
+      bool valid_nonce_length(size_t n) const override
+         { return (n == 12); }
+
+      size_t tag_size() const override { return 16; }
+
+      void clear() override;
+   protected:
+      std::unique_ptr<StreamCipher> m_chacha;
+      std::unique_ptr<MessageAuthenticationCode> m_poly1305;
+
+      secure_vector<byte> m_ad;
+      size_t m_ctext_len = 0;
+
+      void update_len(size_t len);
+   private:
+      secure_vector<byte> start_raw(const byte nonce[], size_t nonce_len) override;
+
+      void key_schedule(const byte key[], size_t length) override;
+   };
+
+/**
+* ChaCha20Poly1305 Encryption
+*/
+class BOTAN_DLL ChaCha20Poly1305_Encryption : public ChaCha20Poly1305_Mode
+   {
+   public:
+      size_t output_length(size_t input_length) const override
+         { return input_length + tag_size(); }
+
+      size_t minimum_final_size() const override { return 0; }
+
+      void update(secure_vector<byte>& blocks, size_t offset = 0) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset = 0) override;
+   };
+
+/**
+* ChaCha20Poly1305 Decryption
+*/
+class BOTAN_DLL ChaCha20Poly1305_Decryption : public ChaCha20Poly1305_Mode
+   {
+   public:
+      size_t output_length(size_t input_length) const override
+         {
+         BOTAN_ASSERT(input_length > tag_size(), "Sufficient input");
+         return input_length - tag_size();
+         }
+
+      size_t minimum_final_size() const override { return tag_size(); }
+
+      void update(secure_vector<byte>& blocks, size_t offset = 0) override;
+
+      void finish(secure_vector<byte>& final_block, size_t offset = 0) override;
+   };
+
+}
+
+#endif