1 files changed, 92 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/stream/ofb/ofb.cpp b/comm/third_party/botan/src/lib/stream/ofb/ofb.cpp
new file mode 100644
index 0000000000..dde4681171
--- /dev/null
+++ b/comm/third_party/botan/src/lib/stream/ofb/ofb.cpp
@@ -0,0 +1,92 @@
+/*
+* OFB Mode
+* (C) 1999-2007,2014 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/ofb.h>
+#include <botan/exceptn.h>
+
+namespace Botan {
+
+OFB::OFB(BlockCipher* cipher) :
+   m_cipher(cipher),
+   m_buffer(m_cipher->block_size()),
+   m_buf_pos(0)
+   {
+   }
+
+void OFB::clear()
+   {
+   m_cipher->clear();
+   zeroise(m_buffer);
+   m_buf_pos = 0;
+   }
+
+void OFB::key_schedule(const uint8_t key[], size_t key_len)
+   {
+   m_cipher->set_key(key, key_len);
+
+   // Set a default all-zeros IV
+   set_iv(nullptr, 0);
+   }
+
+std::string OFB::name() const
+   {
+   return "OFB(" + m_cipher->name() + ")";
+   }
+
+size_t OFB::default_iv_length() const
+   {
+   return m_cipher->block_size();
+   }
+
+bool OFB::valid_iv_length(size_t iv_len) const
+   {
+   return (iv_len <= m_cipher->block_size());
+   }
+
+Key_Length_Specification OFB::key_spec() const
+   {
+   return m_cipher->key_spec();
+   }
+
+OFB* OFB::clone() const
+   {
+   return new OFB(m_cipher->clone());
+   }
+
+void OFB::cipher(const uint8_t in[], uint8_t out[], size_t length)
+   {
+   while(length >= m_buffer.size() - m_buf_pos)
+      {
+      xor_buf(out, in, &m_buffer[m_buf_pos], m_buffer.size() - m_buf_pos);
+      length -= (m_buffer.size() - m_buf_pos);
+      in += (m_buffer.size() - m_buf_pos);
+      out += (m_buffer.size() - m_buf_pos);
+      m_cipher->encrypt(m_buffer);
+      m_buf_pos = 0;
+      }
+   xor_buf(out, in, &m_buffer[m_buf_pos], length);
+   m_buf_pos += length;
+   }
+
+void OFB::set_iv(const uint8_t iv[], size_t iv_len)
+   {
+   if(!valid_iv_length(iv_len))
+      throw Invalid_IV_Length(name(), iv_len);
+
+   zeroise(m_buffer);
+   buffer_insert(m_buffer, 0, iv, iv_len);
+
+   m_cipher->encrypt(m_buffer);
+   m_buf_pos = 0;
+   }
+
+
+void OFB::seek(uint64_t)
+   {
+   throw Not_Implemented("OFB does not support seeking");
+   }
+}