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// Copyright (C) 2011 Internet Systems Consortium, Inc. ("ISC")
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
#include <string>
#include <dns/buffer.h>
#include <exceptions/exceptions.h>
#include <boost/noncopyable.hpp>
#include <cryptolink/crypto.h>
#ifndef _ISC_CRYPTO_HMAC_H
#define _ISC_CRYPTO_HMAC_H
namespace isc {
namespace cryptolink {
/// Forward declaration, pimpl style
class HMACImpl;
/// \brief HMAC support
///
/// This class is used to create and verify HMAC signatures. Instances
/// can be created with CryptoLink::createHMAC()
///
class HMAC : private boost::noncopyable {
public:
enum HashAlgorithm {
MD5 = 0, ///< MD5
SHA1 = 1, ///< SHA-1
SHA256 = 2, ///< SHA-256
UNKNOWN = 3 ///< This value can be used in conversion
/// functions, to be returned when the
/// input is unknown (but a value MUST be
/// returned), for instance when the input
/// is a Name or a string, and the return
/// value is a HashAlgorithm.
};
private:
/// Since HMAC objects cannot be created directly, the factory
/// class CryptoLink is a friend
friend class CryptoLink;
/// \brief Constructor from a secret and a hash algorithm
///
/// \exception UnsupportedAlgorithmException if the given algorithm
/// is unknown or not supported by the underlying library
/// \exception InvalidKeyLength if the given key secret_len is bad
///
/// Notes: if the secret is longer than the block size of its
/// algorithm, the constructor will run it through the hash
/// algorithm, and use the digest as the secret for this HMAC
/// operation
///
/// \param secret The secret to sign with
/// \param len The length of the secret
/// \param hash_algorithm The hash algorithm
HMAC(const void* secret, size_t secret_len,
const HashAlgorithm hash_algorithm);
public:
/// \brief Destructor
~HMAC();
/// \brief Returns the output size of the digest
///
/// \return output size of the digest
size_t getOutputLength() const;
/// \brief Add data to digest
///
/// \param data The data to add
/// \param len The size of the data
void update(const void* data, const size_t len);
/// \brief Calculate the final signature
///
/// The result will be appended to the given outputbuffer
///
/// \param result The OutputBuffer to append the result to
/// \param len The number of bytes from the result to copy. If this
/// value is smaller than the algorithms output size, the
/// result will be truncated. If this value is larger, or 0
/// (the default), it will be ignored
void sign(isc::dns::OutputBuffer& result, size_t len = 0);
/// \brief Calculate the final signature
///
/// len bytes of data from the result will be copied to *result
/// If len is larger than the output size, only output_size bytes
/// will be copied. If it is smaller, the output will be truncated
///
/// At least len bytes of data must be available for writing at
/// result
void sign(void* result, size_t len);
/// \brief Calculate the final signatre
///
/// The result will be returned as a std::vector<uint8_t>
///
/// \param len The number of bytes from the result to copy. If this
/// value is smaller than the algorithms output size, the
/// result will be truncated. If this value is larger, or 0
/// (the default), it will be ignored
/// \return a vector containing the signature
std::vector<uint8_t> sign(size_t len = 0);
/// \brief Verify an existing signature
///
/// \param sig The signature to verify
/// \param len The length of the signature. If this is non-zero,
/// and smaller than the output length of the algorithm,
/// only len bytes will be checked
/// \return true if the signature is correct, false otherwise
bool verify(const void* sig, size_t len);
private:
HMACImpl* impl_;
};
/// \brief Create an HMAC signature for the given data
///
/// This is a convenience function that calculates the hmac signature,
/// given a fixed amount of data. Internally it does the same as
/// creating an HMAC object, feeding it the data, and calculating the
/// resulting signature.
///
/// \exception UnsupportedAlgorithm if the given algorithm is unknown
/// or not supported by the underlying library
/// \exception BadKey if the given key secret_len is bad
///
/// Notes: if the secret is longer than the block size of its
/// algorithm, the constructor will run it through the hash
/// algorithm, and use the digest as the secret for this HMAC
/// operation
///
/// \param data The data to sign
/// \param data_len The length of the data
/// \param secret The secret to sign with
/// \param secret_len The length of the secret
/// \param hash_algorithm The hash algorithm
/// \param result The signature will be appended to this buffer
/// \param len If this is non-zero and less than the output size,
/// the result will be truncated to len bytes
void signHMAC(const void* data,
const size_t data_len,
const void* secret,
size_t secret_len,
const HMAC::HashAlgorithm hash_algorithm,
isc::dns::OutputBuffer& result,
size_t len = 0);
/// \brief Verify an HMAC signature for the given data
///
/// This is a convenience function that verifies an hmac signature,
/// given a fixed amount of data. Internally it does the same as
/// creating an HMAC object, feeding it the data, and checking the
/// resulting signature.
///
/// \exception UnsupportedAlgorithm if the given algorithm is unknown
/// or not supported by the underlying library
/// \exception BadKey if the given key secret_len is bad
///
/// Notes: if the secret is longer than the block size of its
/// algorithm, the constructor will run it through the hash
/// algorithm, and use the digest as the secret for this HMAC
/// operation
///
/// \param data The data to verify
/// \param data_len The length of the data
/// \param secret The secret to sign with
/// \param secret_len The length of the secret
/// \param hash_algorithm The hash algorithm
/// \param sig The signature to verify
/// \param sig_len The length of the signature
/// \return True if the signature verifies, false if not
bool verifyHMAC(const void* data,
const size_t data_len,
const void* secret,
size_t secret_len,
const HMAC::HashAlgorithm hash_algorithm,
const void* sig,
const size_t sig_len);
} // namespace cryptolink
} // namespace isc
#endif // __ISC_CRYPTO_HMAC
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