42 lines
1.1 KiB
Crystal
42 lines
1.1 KiB
Crystal
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module Sodium
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class Kdf
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property bytes : Bytes
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delegate to_slice, to: @bytes
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def initialize(bytes : Bytes)
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if bytes.bytesize != LibSodium::KDF_KEY_SIZE
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raise ArgumentError.new("bytes must be #{LibSodium::KDF_KEY_SIZE}, got #{bytes.bytesize}")
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end
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@bytes = bytes
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end
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def initialize
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@bytes = Random::Secure.random_bytes(LibSodium::KDF_KEY_SIZE)
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end
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# context must be 8 bytes
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# subkey_size must be 16..64 bytes as of libsodium 1.0.17
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def derive(context, subkey_id, subkey_size)
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if context.bytesize != LibSodium::KDF_CONTEXT_SIZE
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raise ArgumentError.new("context must be #{LibSodium::KDF_CONTEXT_SIZE}, got #{context.bytesize}")
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end
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subkey = Bytes.new subkey_size
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if (ret = LibSodium.crypto_kdf_derive_from_key(subkey, subkey.bytesize, subkey_id, context, @bytes)) != 0
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raise Sodium::Error.new("crypto_kdf_derive_from_key returned #{ret} (subkey size is probably out of range)")
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end
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subkey
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end
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def to_base64
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Base64.encode(bytes)
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end
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def self.from_base64(encoded_key)
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new(Base64.decode(encoded_key))
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end
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end
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end
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