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-rw-r--r--src/modes/aead/aead.cpp17
-rw-r--r--src/modes/aead/siv/info.txt3
-rw-r--r--src/modes/aead/siv/siv.cpp183
-rw-r--r--src/modes/aead/siv/siv.h114
4 files changed, 316 insertions, 1 deletions
diff --git a/src/modes/aead/aead.cpp b/src/modes/aead/aead.cpp
index d913c7c3a..26a7091fd 100644
--- a/src/modes/aead/aead.cpp
+++ b/src/modes/aead/aead.cpp
@@ -20,6 +20,10 @@
#include <botan/gcm.h>
#endif
+#if defined(BOTAN_HAS_AEAD_SIV)
+ #include <botan/siv.h>
+#endif
+
#if defined(BOTAN_HAS_AEAD_OCB)
#include <botan/ocb.h>
#endif
@@ -59,7 +63,7 @@ AEAD_Mode* get_aead(const std::string& algo_spec, Cipher_Dir direction)
return new CCM_Decryption(cipher->clone(), 8, 3);
}
- if(mode_name == "CCM")
+ if(mode_name == "CCM" || mode_name == "CCM-8")
{
const size_t L = (mode_info.size() > 2) ? to_u32bit(mode_info[2]) : 3;
@@ -80,6 +84,17 @@ AEAD_Mode* get_aead(const std::string& algo_spec, Cipher_Dir direction)
}
#endif
+#if defined(BOTAN_HAS_AEAD_SIV)
+ if(mode_name == "SIV")
+ {
+ BOTAN_ASSERT(tag_size == 16, "Valid tag size for SIV");
+ if(direction == ENCRYPTION)
+ return new SIV_Encryption(cipher->clone());
+ else
+ return new SIV_Decryption(cipher->clone());
+ }
+#endif
+
#if defined(BOTAN_HAS_AEAD_GCM)
if(mode_name == "GCM")
{
diff --git a/src/modes/aead/siv/info.txt b/src/modes/aead/siv/info.txt
new file mode 100644
index 000000000..b1e38568e
--- /dev/null
+++ b/src/modes/aead/siv/info.txt
@@ -0,0 +1,3 @@
+define AEAD_SIV 20131202
+
+load_on auto
diff --git a/src/modes/aead/siv/siv.cpp b/src/modes/aead/siv/siv.cpp
new file mode 100644
index 000000000..15fb16aa0
--- /dev/null
+++ b/src/modes/aead/siv/siv.cpp
@@ -0,0 +1,183 @@
+/*
+* SIV Mode Encryption
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/siv.h>
+#include <botan/cmac.h>
+#include <botan/ctr.h>
+#include <botan/parsing.h>
+#include <botan/internal/xor_buf.h>
+#include <algorithm>
+
+#include <iostream>
+#include <botan/hex.h>
+
+namespace Botan {
+
+SIV_Mode::SIV_Mode(BlockCipher* cipher) :
+ m_name(cipher->name() + "/SIV"),
+ m_ctr(new CTR_BE(cipher->clone())),
+ m_cmac(new CMAC(cipher))
+ {
+ }
+
+void SIV_Mode::clear()
+ {
+ m_ctr.reset();
+ m_nonce.clear();
+ m_msg_buf.clear();
+ m_ad_macs.clear();
+ }
+
+std::string SIV_Mode::name() const
+ {
+ return m_name;
+ }
+
+bool SIV_Mode::valid_nonce_length(size_t) const
+ {
+ return true;
+ }
+
+size_t SIV_Mode::update_granularity() const
+ {
+ /*
+ This value does not particularly matter as regardless SIV_Mode::update
+ buffers all input, so in theory this could be 1. However as for instance
+ Transformation_Filter creates update_granularity() byte buffers, use a
+ somewhat large size to avoid bouncing on a tiny buffer.
+ */
+ return 128;
+ }
+
+Key_Length_Specification SIV_Mode::key_spec() const
+ {
+ return m_cmac->key_spec().multiple(2);
+ }
+
+void SIV_Mode::key_schedule(const byte key[], size_t length)
+ {
+ const size_t keylen = length / 2;
+ m_cmac->set_key(key, keylen);
+ m_ctr->set_key(key + keylen, keylen);
+ m_ad_macs.clear();
+ }
+
+void SIV_Mode::set_associated_data_n(size_t n, const byte ad[], size_t length)
+ {
+ if(n >= m_ad_macs.size())
+ m_ad_macs.resize(n+1);
+
+ m_ad_macs[n] = m_cmac->process(ad, length);
+ }
+
+secure_vector<byte> SIV_Mode::start(const byte nonce[], size_t nonce_len)
+ {
+ if(!valid_nonce_length(nonce_len))
+ throw Invalid_IV_Length(name(), nonce_len);
+
+ if(nonce_len)
+ m_nonce = m_cmac->process(nonce, nonce_len);
+ else
+ m_nonce.clear();
+
+ m_msg_buf.clear();
+
+ return secure_vector<byte>();
+ }
+
+void SIV_Mode::update(secure_vector<byte>& buffer, size_t offset)
+ {
+ BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+ const size_t sz = buffer.size() - offset;
+ byte* buf = &buffer[offset];
+
+ m_msg_buf.insert(m_msg_buf.end(), buf, buf + sz);
+ buffer.resize(offset); // truncate msg
+ }
+
+secure_vector<byte> SIV_Mode::S2V(const byte* text, size_t text_len)
+ {
+ const byte zero[16] = { 0 };
+
+ secure_vector<byte> V = cmac().process(zero, 16);
+
+ for(size_t i = 0; i != m_ad_macs.size(); ++i)
+ {
+ V = CMAC::poly_double(V, 0x87);
+ V ^= m_ad_macs[i];
+ }
+
+ if(m_nonce.size())
+ {
+ V = CMAC::poly_double(V, 0x87);
+ V ^= m_nonce;
+ }
+
+ if(text_len < 16)
+ {
+ V = CMAC::poly_double(V, 0x87);
+ xor_buf(&V[0], text, text_len);
+ V[text_len] ^= 0x80;
+ return cmac().process(V);
+ }
+
+ cmac().update(text, text_len - 16);
+ xor_buf(&V[0], &text[text_len - 16], 16);
+ cmac().update(V);
+
+ return cmac().final();
+ }
+
+void SIV_Mode::set_ctr_iv(secure_vector<byte> V)
+ {
+ V[8] &= 0x7F;
+ V[12] &= 0x7F;
+
+ ctr().set_iv(&V[0], V.size());
+ }
+
+void SIV_Encryption::finish(secure_vector<byte>& buffer, size_t offset)
+ {
+ BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+
+ buffer.insert(buffer.begin() + offset, msg_buf().begin(), msg_buf().end());
+
+ secure_vector<byte> V = S2V(&buffer[offset], buffer.size() - offset);
+
+ buffer.insert(buffer.begin() + offset, V.begin(), V.end());
+
+ set_ctr_iv(V);
+ ctr().cipher1(&buffer[offset + V.size()], buffer.size() - offset - V.size());
+ }
+
+void SIV_Decryption::finish(secure_vector<byte>& buffer, size_t offset)
+ {
+ BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+
+ buffer.insert(buffer.begin() + offset, msg_buf().begin(), msg_buf().end());
+
+ const size_t sz = buffer.size() - offset;
+
+ BOTAN_ASSERT(sz >= tag_size(), "We have the tag");
+
+ secure_vector<byte> V(&buffer[offset], &buffer[offset + 16]);
+
+ set_ctr_iv(V);
+
+ ctr().cipher(&buffer[offset + V.size()],
+ &buffer[offset],
+ buffer.size() - offset - V.size());
+
+ secure_vector<byte> T = S2V(&buffer[offset], buffer.size() - offset - V.size());
+
+ if(T != V)
+ throw Integrity_Failure("SIV tag check failed");
+
+ buffer.resize(buffer.size() - tag_size());
+ }
+
+}
diff --git a/src/modes/aead/siv/siv.h b/src/modes/aead/siv/siv.h
new file mode 100644
index 000000000..612d29bb7
--- /dev/null
+++ b/src/modes/aead/siv/siv.h
@@ -0,0 +1,114 @@
+/*
+* SIV Mode
+* (C) 2013 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#ifndef BOTAN_AEAD_SIV_H__
+#define BOTAN_AEAD_SIV_H__
+
+#include <botan/aead.h>
+#include <botan/block_cipher.h>
+#include <botan/stream_cipher.h>
+#include <botan/mac.h>
+#include <memory>
+
+namespace Botan {
+
+/**
+* Base class for SIV encryption and decryption (@see RFC 5297)
+*/
+class BOTAN_DLL SIV_Mode : public AEAD_Mode
+ {
+ public:
+ secure_vector<byte> start(const byte nonce[], size_t nonce_len) override;
+
+ void update(secure_vector<byte>& blocks, size_t offset) override;
+
+ void set_associated_data_n(size_t n, const byte ad[], size_t ad_len);
+
+ void set_associated_data(const byte ad[], size_t ad_len) override
+ {
+ set_associated_data_n(0, ad, ad_len);
+ }
+
+ std::string name() const override;
+
+ size_t update_granularity() const;
+
+ Key_Length_Specification key_spec() const override;
+
+ bool valid_nonce_length(size_t) const override;
+
+ void clear();
+
+ size_t tag_size() const { return 16; }
+
+ protected:
+ SIV_Mode(BlockCipher* cipher);
+
+ StreamCipher& ctr() { return *m_ctr; }
+
+ void set_ctr_iv(secure_vector<byte> V);
+
+ secure_vector<byte>& msg_buf() { return m_msg_buf; }
+
+ secure_vector<byte> S2V(const byte text[], size_t text_len);
+ private:
+ MessageAuthenticationCode& cmac() { return *m_cmac; }
+
+ void key_schedule(const byte key[], size_t length) override;
+
+ const std::string m_name;
+
+ std::unique_ptr<StreamCipher> m_ctr;
+ std::unique_ptr<MessageAuthenticationCode> m_cmac;
+ secure_vector<byte> m_nonce, m_msg_buf;
+ std::vector<secure_vector<byte>> m_ad_macs;
+ };
+
+/**
+* SIV Encryption
+*/
+class BOTAN_DLL SIV_Encryption : public SIV_Mode
+ {
+ public:
+ /**
+ * @param cipher a block cipher
+ */
+ SIV_Encryption(BlockCipher* cipher) : SIV_Mode(cipher) {}
+
+ void finish(secure_vector<byte>& final_block, size_t offset) override;
+
+ size_t output_length(size_t input_length) const override
+ { return input_length + tag_size(); }
+
+ size_t minimum_final_size() const override { return 0; }
+ };
+
+/**
+* SIV Decryption
+*/
+class BOTAN_DLL SIV_Decryption : public SIV_Mode
+ {
+ public:
+ /**
+ * @param cipher a 128-bit block cipher
+ */
+ SIV_Decryption(BlockCipher* cipher) : SIV_Mode(cipher) {}
+
+ void finish(secure_vector<byte>& final_block, size_t offset) override;
+
+ 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(); }
+ };
+
+}
+
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 02:41:42 +0000