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38 lines
1.3 KiB
Plaintext
38 lines
1.3 KiB
Plaintext
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.. _key_derivation_function:
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Key Derivation Functions
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========================================
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Key derivation functions are used to turn some amount of shared secret
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material into uniform random keys suitable for use with symmetric
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algorithms. An example of an input which is useful for a KDF is a
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shared secret created using Diffie-Hellman key agreement.
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.. cpp:class:: KDF
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.. cpp:function:: SecureVector<byte> derive_key( \
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size_t key_len, const MemoryRegion<byte>& secret, \
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const std::string& salt = "") const
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.. cpp:function:: SecureVector<byte> derive_key( \
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size_t key_len, const MemoryRegion<byte>& secret, \
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const MemoryRegion<byte>& salt) const
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.. cpp:function:: SecureVector<byte> derive_key( \
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size_t key_len, const MemoryRegion<byte>& secret, \
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const byte* salt, size_t salt_len) const
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.. cpp:function:: SecureVector<byte> derive_key( \
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size_t key_len, const byte* secret, size_t secret_len, \
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const std::string& salt) const
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All variations on the same theme. Deterministically creates a
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uniform random value from *secret* and *salt*. Typically *salt* is
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a lable or identifier, such as a session id.
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You can create a :cpp:class:`KDF` using
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.. cpp:function:: KDF* get_kdf(const std::string& algo_spec)
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