65 lines
1.9 KiB
Crystal
65 lines
1.9 KiB
Crystal
require "./lib_sodium"
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require "./wipe"
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require "./crypto_box/secret_key"
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require "./nonce"
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module Sodium
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# Use Sodium::CryptoBox::SecretKey#box
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class CryptoBox
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include Wipe
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MAC_SIZE = LibSodium.crypto_box_macbytes.to_i
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# :nodoc:
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NM_SIZE = LibSodium.crypto_box_beforenmbytes.to_i
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raise "NM_SIZE=#{NM_SIZE}, assumed it was 32" if NM_SIZE != 32
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@[Wipe::Var]
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@key = StaticArray(UInt8, 32).new 0
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# :nodoc:
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# Used by SecretKey#box
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def initialize(@secret_key : SecretKey, @public_key : PublicKey)
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# Precalculate key for later use.
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# Large speed gains with small data sizes and many messages.
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# Small speed gains with large data sizes or few messages.
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if LibSodium.crypto_box_beforenm(@key, @public_key.to_slice, @secret_key.to_slice) != 0
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raise Error.new("crypto_box_beforenm")
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end
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end
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# Encrypts data and returns {ciphertext, nonce}
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def encrypt(src)
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encrypt src.to_slice
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end
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# Encrypts data and returns {ciphertext, nonce}
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#
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# Optionally supply a destination buffer.
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def encrypt(src : Bytes, dst = Bytes.new(src.bytesize + MAC_SIZE), nonce = Nonce.random) : {Bytes, Nonce}
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nonce.used!
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if LibSodium.crypto_box_easy_afternm(dst, src, src.bytesize, nonce.to_slice, @key.to_slice) != 0
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raise Error.new("crypto_box_easy")
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end
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{dst, nonce}
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end
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# Returns decrypted message.
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#
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def decrypt(src)
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decrypt src.to_slice
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end
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# Returns decrypted message.
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#
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# Optionally supply a destination buffer.
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def decrypt(src : Bytes, dst = Bytes.new(src.bytesize - MAC_SIZE), nonce = Nonce.random) : Bytes
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if LibSodium.crypto_box_open_easy_afternm(dst, src, src.bytesize, nonce.to_slice, @key) != 0
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raise Error::DecryptionFailed.new("crypto_box_open_easy")
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end
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dst
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end
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# TODO detached
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end
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end
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