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Diffstat (limited to 'src/lib/pubkey/xmss/xmss_privatekey.h')
| -rw-r--r-- | src/lib/pubkey/xmss/xmss_privatekey.h | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/src/lib/pubkey/xmss/xmss_privatekey.h b/src/lib/pubkey/xmss/xmss_privatekey.h new file mode 100644 index 000000000..064d899a8 --- /dev/null +++ b/src/lib/pubkey/xmss/xmss_privatekey.h @@ -0,0 +1,258 @@ +/** + * XMSS_PrivateKey.h + * (C) 2016 Matthias Gierlings + * + * Botan is released under the Simplified BSD License (see license.txt) + **/ + +#ifndef BOTAN_XMSS_PRIVATEKEY_H__ +#define BOTAN_XMSS_PRIVATEKEY_H__ + +#include <cstddef> +#include <iterator> +#include <memory> +#include <botan/alg_id.h> +#include <botan/assert.h> +#include <botan/exceptn.h> +#include <botan/pk_keys.h> +#include <botan/rng.h> +#include <botan/types.h> +#include <botan/xmss_parameters.h> +#include <botan/xmss_publickey.h> +#include <botan/atomic.h> +#include <botan/xmss_common_ops.h> +#include <botan/xmss_wots_privatekey.h> +#include <botan/xmss_index_registry.h> + +namespace Botan { + +/** + * An XMSS: Extended Hash-Based Signature private key. + * The XMSS private key does not support the X509 and PKCS7 standard. Instead + * the raw format described in [1] is used. + * + * [1] XMSS: Extended Hash-Based Signatures, + * draft-itrf-cfrg-xmss-hash-based-signatures-06 + * Release: July 2016. + * https://datatracker.ietf.org/doc/ + * draft-irtf-cfrg-xmss-hash-based-signatures/?include_text=1 + **/ +class BOTAN_DLL XMSS_PrivateKey : public virtual XMSS_PublicKey, + public XMSS_Common_Ops, + public virtual Private_Key + { + public: + /** + * Creates a new XMSS private key for the chosen XMSS signature method. + * New seeds for public/private key and pseudo random function input are + * generated using AutoSeeded_RNG. The appropriate WOTS signature method + * will be automatically set based on the chosen XMSS signature method. + * + * @param xmss_algo_id Identifier for the selected XMSS signature method. + * @param rng A random number generator to use for key generation. + **/ + XMSS_PrivateKey(XMSS_Parameters::xmss_algorithm_t xmss_algo_id, + RandomNumberGenerator& rng); + + /** + * Creates an XMSS_PrivateKey from a byte sequence produced by + * raw_private_key(). + * + * @param raw_key An XMSS private key serialized using raw_private_key(). + **/ + XMSS_PrivateKey(const secure_vector<byte>& raw_key); + + /** + * Creates a new XMSS private key for the chosen XMSS signature method + * using precomputed seeds for public/private keys and pseudo random + * function input. The appropriate WOTS signature method will be + * automatically set, based on the chosen XMSS signature method. + * + * @param xmss_algo_id Identifier for the selected XMSS signature method. + * @param idx_leaf Index of the next unused leaf. + * @param wots_priv_seed A seed to generate a Winternitz-One-Time- + * Signature private key from. + * @param prf a secret n-byte key sourced from a secure source + * of uniformly random data. + * @param root Root node of the binary hash tree. + * @param public_seed The public seed. + **/ + XMSS_PrivateKey(XMSS_Parameters::xmss_algorithm_t xmss_algo_id, + size_t idx_leaf, + const secure_vector<byte>& wots_priv_seed, + const secure_vector<byte>& prf, + const secure_vector<byte>& root, + const secure_vector<byte>& public_seed) + : XMSS_PublicKey(xmss_algo_id, root, public_seed), + XMSS_Common_Ops(xmss_algo_id), + m_wots_priv_key(XMSS_PublicKey::m_xmss_params.ots_oid(), + public_seed, + wots_priv_seed), + m_prf(prf), + m_index_reg(XMSS_Index_Registry::get_instance()) + { + set_unused_leaf_index(idx_leaf); + } + + /** + * Retrieves the last unused leaf index of the private key. Reusing a leaf + * by utilizing leaf indices lower than the last unused leaf index will + * compromise security. + * + * @return Index of the last unused leaf. + **/ + size_t unused_leaf_index() const + { + return *recover_global_leaf_index(); + } + + /** + * Sets the last unused leaf index of the private key. The leaf index + * will be updated automatically during every signing operation, and + * should not be set manually. + * + * @param idx Index of the last unused leaf. + **/ + void set_unused_leaf_index(size_t idx) + { + if(idx >= (1ull << (XMSS_PublicKey::m_xmss_params.tree_height() - 1))) + { + throw Integrity_Failure("XMSS private key leaf index out of " + "bounds."); + } + else + { + std::atomic<size_t>& index = + static_cast<std::atomic<size_t>&>(*recover_global_leaf_index()); + size_t current = 0; + + do + { + current = index.load(); + if(current > idx) + return; + } + while(!index.compare_exchange_strong(current, idx)); + } + } + + size_t reserve_unused_leaf_index() + { + size_t idx = (static_cast<std::atomic<size_t>&>( + *recover_global_leaf_index())).fetch_add(1); + if(idx >= (1ull << (XMSS_PublicKey::m_xmss_params.tree_height() - 1))) + { + throw Integrity_Failure("XMSS private key, one time signatures " + "exhausted."); + } + return idx; + } + + /** + * Winternitz One Time Signature Scheme key utilized for signing + * operations. + * + * @return WOTS+ private key. + **/ + const XMSS_WOTS_PrivateKey& wots_private_key() const + { + return m_wots_priv_key; + } + + /** + * Winternitz One Time Signature Scheme key utilized for signing + * operations. + * + * @return WOTS+ private key. + **/ + XMSS_WOTS_PrivateKey& wots_private_key() + { + return m_wots_priv_key; + } + + const secure_vector<byte>& prf() const + { + return m_prf; + } + + secure_vector<byte>& prf() + { + return m_prf; + } + + virtual void set_public_seed( + const secure_vector<byte>& public_seed) override + { + m_public_seed = public_seed; + m_wots_priv_key.set_public_seed(public_seed); + } + + virtual void set_public_seed(secure_vector<byte>&& public_seed) override + { + m_public_seed = std::move(public_seed); + m_wots_priv_key.set_public_seed(m_public_seed); + } + + virtual const secure_vector<byte>& public_seed() const override + { + return m_public_seed; + } + + virtual std::unique_ptr<PK_Ops::Signature> + create_signature_op(RandomNumberGenerator&, + const std::string&, + const std::string& provider) const override; + + virtual secure_vector<byte> pkcs8_private_key() const override + { + return raw_private_key(); + } + + virtual size_t size() const override + { + return XMSS_PublicKey::size() + + sizeof(uint64_t) + + 2 * XMSS_PublicKey::m_xmss_params.element_size(); + } + + /** + * Generates a non standartized byte sequence representing the XMSS + * private key. + * + * @return byte sequence consisting of the following elements in order: + * 4-byte OID, n-byte root node, n-byte public seed, + * 8-byte unused leaf index, n-byte prf seed, n-byte private seed. + **/ + virtual secure_vector<byte> raw_private_key() const; + /** + * Algorithm 9: "treeHash" + * Computes the internal n-byte nodes of a Merkle tree. + * + * @param start_idx The start index. + * @param target_node_height Height of the target node. + * @param adrs Address of the tree containing the target node. + * + * @return The root node of a tree of height target_node height with the + * leftmost leaf being the hash of the WOTS+ pk with index + * start_idx. + **/ + secure_vector<byte> tree_hash( + size_t start_idx, + size_t target_node_height, + XMSS_Address& adrs); + + private: + /** + * Fetches shared unused leaf index fromt the index registry + **/ + std::shared_ptr<Atomic<size_t>> recover_global_leaf_index() const; + + XMSS_WOTS_PrivateKey m_wots_priv_key; + secure_vector<byte> m_prf; + XMSS_Index_Registry& m_index_reg; + }; + +} + +#endif + |