Module: Aes

Defined in:
lib/ruby-aes.rb

Overview

This file is a part of ruby-aes <rubyforge.org/projects/ruby-aes>

Written by Alex Boussinet <[email protected]>

Valid modes are:

* ECB (Electronic Code Book)
* CBC (Cipher Block Chaining)
* OFB (Output Feedback)
* CFB (Cipher Feedback)

Valid key length:

* 128 bits
* 192 bits
* 256 bits

API calls:

Default key_length: 128
Default mode: 'ECB'
Default IV: 16 null chars ("00" * 16 in hex format)
Default key: 16 null chars ("00" * 16 in hex format)
Default input text: "PLAINTEXT"

Aes.check_key(key_string, key_length)
Aes.check_iv(iv_string)
Aes.check_kl(key_length)
Aes.check_mode(mode)
Aes.init(key_length, mode, key, iv)
Aes.encrypt_block(key_length, mode, key, iv, block) # no padding
Aes.decrypt_block(key_length, mode, key, iv, block) # no padding
Aes.encrypt_buffer(key_length, mode, key, iv, block) # padding
Aes.decrypt_buffer(key_length, mode, key, iv, block) # padding
Aes.encrypt_stream(key_length, mode, key, iv, sin, sout)
Aes.decrypt_stream(key_length, mode, key, iv, sin, sout)
Aes.bs() # block size for read operations (stream)
Aes.bs=(bs)

Constant Summary collapse

@@aes = 
nil
@@bs = 
4096

Class Method Summary collapse

Class Method Details

.bs ⇒ Object 



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# File 'lib/ruby-aes.rb', line 45

def Aes.bs(); return @@bs end

.bs=(bs) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 46

def Aes.bs=(bs); @@bs = bs.to_i; @@bs==0 ? 4096 : @@bs = @@bs - @@bs%16 end

.check_iv(iv_string) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 61

def Aes.check_iv(iv_string)
    k = iv_string.length
    hex = (iv_string =~ /[a-f0-9A-F]{#{k}}/) == 0
    bin = ! hex
    if k == 32 && hex
        return [iv_string].pack("H*")
    elsif k == 16 && bin
        return iv_string
    else
        raise "Bad IV string"
    end
end

.check_key(key_string, kl = 128) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 48

def Aes.check_key(key_string, kl = 128)
    kl = Aes.check_kl(kl)
    k = key_string ? key_string.length : 0
    raise "Bad key string or bad key length" if (k != kl/8) && (k != kl/4)
    hex = (key_string =~ /[a-f0-9A-F]{#{k}}/) == 0 && (k == kl/4)
    bin = ! hex
    if ! (([32, 48, 64].include?(k) && hex) ||
       ([16, 24, 32].include?(k) && bin))
        raise "Bad key string"
    end
    hex ? [key_string].pack("H*") : key_string
end

.check_kl(key_length) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 82

def Aes.check_kl(key_length)
    case key_length
    when 128, 192, 256
    else raise "Bad key length"
    end
    key_length
end

.check_mode(mode) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 74

def Aes.check_mode (mode)
    case mode
    when 'ECB', 'CBC', 'OFB', 'CFB'
    else raise "Bad cipher mode"
    end
    mode
end

.decrypt_block(keyl, mode, key, iv, block = "DEFAULT PLAINTXT") ⇒ Object 



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# File 'lib/ruby-aes.rb', line 106

def Aes.decrypt_block(keyl, mode, key, iv, block = "DEFAULT PLAINTXT")
    Aes.init(keyl, mode, key, iv)
    @@aes.decrypt_block(block)
end

.decrypt_buffer(keyl, mode, key, iv, buffer = "DEFAULT PLAINTXT") ⇒ Object 



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# File 'lib/ruby-aes.rb', line 116

def Aes.decrypt_buffer(keyl, mode, key, iv, buffer = "DEFAULT PLAINTXT")
    raise "Bad Block size" if buffer.length < 16
    Aes.init(keyl, mode, key, iv)
    @@aes.decrypt_buffer(buffer)
end

.decrypt_stream(keyl, mode, key, iv, sin = STDIN, sout = STDOUT) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 145

def Aes.decrypt_stream(keyl, mode, key, iv, sin = STDIN, sout = STDOUT)
    Aes.init(keyl, mode, key, iv)
    case sout
    when String, Array, IO
    else
        raise "Bad output stream (String, Array, IO)"
    end
    case sin
    when String
        sout << @@aes.decrypt_buffer(sin)
    when IO
        while buf = sin.read(@@bs)#+1)
          if buf.length == @@bs
            sout << @@aes.decrypt_blocks(buf)
          else
            sout << @@aes.decrypt_buffer(buf)
          end
        end
    else
        raise "Bad input stream (String, IO)"
    end
end

.encrypt_block(keyl, mode, key, iv, block = "DEFAULT PLAINTXT") ⇒ Object 



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# File 'lib/ruby-aes.rb', line 100

def Aes.encrypt_block(keyl, mode, key, iv, block = "DEFAULT PLAINTXT")
    raise "Bad Block size" if block.length < 16 || block.length > 16
    Aes.init(keyl, mode, key, iv)
    @@aes.encrypt_block(block)
end

.encrypt_buffer(keyl, mode, key, iv, buffer = "PLAINTEXT") ⇒ Object 



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# File 'lib/ruby-aes.rb', line 111

def Aes.encrypt_buffer(keyl, mode, key, iv, buffer = "PLAINTEXT")
    Aes.init(keyl, mode, key, iv)
    @@aes.encrypt_buffer(buffer)
end

.encrypt_stream(keyl, mode, key, iv, sin = STDIN, sout = STDOUT) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 122

def Aes.encrypt_stream(keyl, mode, key, iv, sin = STDIN, sout = STDOUT)
    Aes.init(keyl, mode, key, iv)
    case sout
    when String, Array, IO
    else
        raise "Bad output stream (String, Array, IO)"
    end
    case sin
    when String
        sout << @@aes.encrypt_buffer(sin)
    when IO
        while buf = sin.read(@@bs)
          if buf.length == @@bs
            sout << @@aes.encrypt_blocks(buf)
          else
            sout << @@aes.encrypt_buffer(buf)
          end
        end
    else
        raise "Bad input stream (String, IO)"
    end
end

.init(keyl, mode, key, iv) ⇒ Object 



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# File 'lib/ruby-aes.rb', line 90

def Aes.init(keyl, mode, key, iv)
    unless @@aes
        @@aes = AesAlg.new(Aes.check_kl(keyl), Aes.check_mode(mode),
                           Aes.check_key(key, keyl), iv ? Aes.check_iv(iv) : nil)
    else
        @@aes.init(Aes.check_kl(keyl), Aes.check_mode(mode),
                   Aes.check_key(key, keyl), iv ? Aes.check_iv(iv) : nil)
    end
end