github.com/amanya/packer@v0.12.1-0.20161117214323-902ac5ab2eb6/builder/azure/pkcs12/rc2/rc2.go (about)

     1  // Package rc2 implements the RC2 cipher
     2  /*
     3  https://www.ietf.org/rfc/rfc2268.txt
     4  http://people.csail.mit.edu/rivest/pubs/KRRR98.pdf
     5  
     6  This code is licensed under the MIT license.
     7  */
     8  package rc2
     9  
    10  import (
    11  	"crypto/cipher"
    12  	"encoding/binary"
    13  	"strconv"
    14  )
    15  
    16  // The rc2 block size in bytes
    17  const BlockSize = 8
    18  
    19  type rc2Cipher struct {
    20  	k [64]uint16
    21  }
    22  
    23  // KeySizeError indicates the supplied key was invalid
    24  type KeySizeError int
    25  
    26  func (k KeySizeError) Error() string { return "rc2: invalid key size " + strconv.Itoa(int(k)) }
    27  
    28  // EffectiveKeySizeError indicates the supplied effective key length was invalid
    29  type EffectiveKeySizeError int
    30  
    31  func (k EffectiveKeySizeError) Error() string {
    32  	return "rc2: invalid effective key size " + strconv.Itoa(int(k))
    33  }
    34  
    35  // New returns a new rc2 cipher with the given key and effective key length t1
    36  func New(key []byte, t1 int) (cipher.Block, error) {
    37  	if l := len(key); l == 0 || l > 128 {
    38  		return nil, KeySizeError(l)
    39  	}
    40  
    41  	if t1 < 8 || t1 > 1024 {
    42  		return nil, EffectiveKeySizeError(t1)
    43  	}
    44  
    45  	return &rc2Cipher{
    46  		k: expandKey(key, t1),
    47  	}, nil
    48  }
    49  
    50  func (c *rc2Cipher) BlockSize() int { return BlockSize }
    51  
    52  var piTable = [256]byte{
    53  	0xd9, 0x78, 0xf9, 0xc4, 0x19, 0xdd, 0xb5, 0xed, 0x28, 0xe9, 0xfd, 0x79, 0x4a, 0xa0, 0xd8, 0x9d,
    54  	0xc6, 0x7e, 0x37, 0x83, 0x2b, 0x76, 0x53, 0x8e, 0x62, 0x4c, 0x64, 0x88, 0x44, 0x8b, 0xfb, 0xa2,
    55  	0x17, 0x9a, 0x59, 0xf5, 0x87, 0xb3, 0x4f, 0x13, 0x61, 0x45, 0x6d, 0x8d, 0x09, 0x81, 0x7d, 0x32,
    56  	0xbd, 0x8f, 0x40, 0xeb, 0x86, 0xb7, 0x7b, 0x0b, 0xf0, 0x95, 0x21, 0x22, 0x5c, 0x6b, 0x4e, 0x82,
    57  	0x54, 0xd6, 0x65, 0x93, 0xce, 0x60, 0xb2, 0x1c, 0x73, 0x56, 0xc0, 0x14, 0xa7, 0x8c, 0xf1, 0xdc,
    58  	0x12, 0x75, 0xca, 0x1f, 0x3b, 0xbe, 0xe4, 0xd1, 0x42, 0x3d, 0xd4, 0x30, 0xa3, 0x3c, 0xb6, 0x26,
    59  	0x6f, 0xbf, 0x0e, 0xda, 0x46, 0x69, 0x07, 0x57, 0x27, 0xf2, 0x1d, 0x9b, 0xbc, 0x94, 0x43, 0x03,
    60  	0xf8, 0x11, 0xc7, 0xf6, 0x90, 0xef, 0x3e, 0xe7, 0x06, 0xc3, 0xd5, 0x2f, 0xc8, 0x66, 0x1e, 0xd7,
    61  	0x08, 0xe8, 0xea, 0xde, 0x80, 0x52, 0xee, 0xf7, 0x84, 0xaa, 0x72, 0xac, 0x35, 0x4d, 0x6a, 0x2a,
    62  	0x96, 0x1a, 0xd2, 0x71, 0x5a, 0x15, 0x49, 0x74, 0x4b, 0x9f, 0xd0, 0x5e, 0x04, 0x18, 0xa4, 0xec,
    63  	0xc2, 0xe0, 0x41, 0x6e, 0x0f, 0x51, 0xcb, 0xcc, 0x24, 0x91, 0xaf, 0x50, 0xa1, 0xf4, 0x70, 0x39,
    64  	0x99, 0x7c, 0x3a, 0x85, 0x23, 0xb8, 0xb4, 0x7a, 0xfc, 0x02, 0x36, 0x5b, 0x25, 0x55, 0x97, 0x31,
    65  	0x2d, 0x5d, 0xfa, 0x98, 0xe3, 0x8a, 0x92, 0xae, 0x05, 0xdf, 0x29, 0x10, 0x67, 0x6c, 0xba, 0xc9,
    66  	0xd3, 0x00, 0xe6, 0xcf, 0xe1, 0x9e, 0xa8, 0x2c, 0x63, 0x16, 0x01, 0x3f, 0x58, 0xe2, 0x89, 0xa9,
    67  	0x0d, 0x38, 0x34, 0x1b, 0xab, 0x33, 0xff, 0xb0, 0xbb, 0x48, 0x0c, 0x5f, 0xb9, 0xb1, 0xcd, 0x2e,
    68  	0xc5, 0xf3, 0xdb, 0x47, 0xe5, 0xa5, 0x9c, 0x77, 0x0a, 0xa6, 0x20, 0x68, 0xfe, 0x7f, 0xc1, 0xad,
    69  }
    70  
    71  func expandKey(key []byte, t1 int) [64]uint16 {
    72  
    73  	l := make([]byte, 128)
    74  	copy(l, key)
    75  
    76  	var t = len(key)
    77  	var t8 = (t1 + 7) / 8
    78  	var tm = byte(255 % uint(1<<(8+uint(t1)-8*uint(t8))))
    79  
    80  	for i := len(key); i < 128; i++ {
    81  		l[i] = piTable[l[i-1]+l[uint8(i-t)]]
    82  	}
    83  
    84  	l[128-t8] = piTable[l[128-t8]&tm]
    85  
    86  	for i := 127 - t8; i >= 0; i-- {
    87  		l[i] = piTable[l[i+1]^l[i+t8]]
    88  	}
    89  
    90  	var k [64]uint16
    91  
    92  	for i := range k {
    93  		k[i] = uint16(l[2*i]) + uint16(l[2*i+1])*256
    94  	}
    95  
    96  	return k
    97  }
    98  
    99  func rotl16(x uint16, b uint) uint16 {
   100  	return (x >> (16 - b)) | (x << b)
   101  }
   102  
   103  func (c *rc2Cipher) Encrypt(dst, src []byte) {
   104  
   105  	r0 := binary.LittleEndian.Uint16(src[0:])
   106  	r1 := binary.LittleEndian.Uint16(src[2:])
   107  	r2 := binary.LittleEndian.Uint16(src[4:])
   108  	r3 := binary.LittleEndian.Uint16(src[6:])
   109  
   110  	var j int
   111  
   112  	// These three mix blocks have not been extracted to a common function for to performance reasons.
   113  	for j <= 16 {
   114  		// mix r0
   115  		r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1)
   116  		r0 = rotl16(r0, 1)
   117  		j++
   118  
   119  		// mix r1
   120  		r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2)
   121  		r1 = rotl16(r1, 2)
   122  		j++
   123  
   124  		// mix r2
   125  		r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3)
   126  		r2 = rotl16(r2, 3)
   127  		j++
   128  
   129  		// mix r3
   130  		r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0)
   131  		r3 = rotl16(r3, 5)
   132  		j++
   133  	}
   134  
   135  	r0 = r0 + c.k[r3&63]
   136  	r1 = r1 + c.k[r0&63]
   137  	r2 = r2 + c.k[r1&63]
   138  	r3 = r3 + c.k[r2&63]
   139  
   140  	for j <= 40 {
   141  		// mix r0
   142  		r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1)
   143  		r0 = rotl16(r0, 1)
   144  		j++
   145  
   146  		// mix r1
   147  		r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2)
   148  		r1 = rotl16(r1, 2)
   149  		j++
   150  
   151  		// mix r2
   152  		r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3)
   153  		r2 = rotl16(r2, 3)
   154  		j++
   155  
   156  		// mix r3
   157  		r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0)
   158  		r3 = rotl16(r3, 5)
   159  		j++
   160  	}
   161  
   162  	r0 = r0 + c.k[r3&63]
   163  	r1 = r1 + c.k[r0&63]
   164  	r2 = r2 + c.k[r1&63]
   165  	r3 = r3 + c.k[r2&63]
   166  
   167  	for j <= 60 {
   168  		// mix r0
   169  		r0 = r0 + c.k[j] + (r3 & r2) + ((^r3) & r1)
   170  		r0 = rotl16(r0, 1)
   171  		j++
   172  
   173  		// mix r1
   174  		r1 = r1 + c.k[j] + (r0 & r3) + ((^r0) & r2)
   175  		r1 = rotl16(r1, 2)
   176  		j++
   177  
   178  		// mix r2
   179  		r2 = r2 + c.k[j] + (r1 & r0) + ((^r1) & r3)
   180  		r2 = rotl16(r2, 3)
   181  		j++
   182  
   183  		// mix r3
   184  		r3 = r3 + c.k[j] + (r2 & r1) + ((^r2) & r0)
   185  		r3 = rotl16(r3, 5)
   186  		j++
   187  	}
   188  
   189  	binary.LittleEndian.PutUint16(dst[0:], r0)
   190  	binary.LittleEndian.PutUint16(dst[2:], r1)
   191  	binary.LittleEndian.PutUint16(dst[4:], r2)
   192  	binary.LittleEndian.PutUint16(dst[6:], r3)
   193  }
   194  
   195  func (c *rc2Cipher) Decrypt(dst, src []byte) {
   196  
   197  	r0 := binary.LittleEndian.Uint16(src[0:])
   198  	r1 := binary.LittleEndian.Uint16(src[2:])
   199  	r2 := binary.LittleEndian.Uint16(src[4:])
   200  	r3 := binary.LittleEndian.Uint16(src[6:])
   201  
   202  	j := 63
   203  
   204  	for j >= 44 {
   205  		// unmix r3
   206  		r3 = rotl16(r3, 16-5)
   207  		r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0)
   208  		j--
   209  
   210  		// unmix r2
   211  		r2 = rotl16(r2, 16-3)
   212  		r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3)
   213  		j--
   214  
   215  		// unmix r1
   216  		r1 = rotl16(r1, 16-2)
   217  		r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2)
   218  		j--
   219  
   220  		// unmix r0
   221  		r0 = rotl16(r0, 16-1)
   222  		r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1)
   223  		j--
   224  	}
   225  
   226  	r3 = r3 - c.k[r2&63]
   227  	r2 = r2 - c.k[r1&63]
   228  	r1 = r1 - c.k[r0&63]
   229  	r0 = r0 - c.k[r3&63]
   230  
   231  	for j >= 20 {
   232  		// unmix r3
   233  		r3 = rotl16(r3, 16-5)
   234  		r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0)
   235  		j--
   236  
   237  		// unmix r2
   238  		r2 = rotl16(r2, 16-3)
   239  		r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3)
   240  		j--
   241  
   242  		// unmix r1
   243  		r1 = rotl16(r1, 16-2)
   244  		r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2)
   245  		j--
   246  
   247  		// unmix r0
   248  		r0 = rotl16(r0, 16-1)
   249  		r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1)
   250  		j--
   251  	}
   252  
   253  	r3 = r3 - c.k[r2&63]
   254  	r2 = r2 - c.k[r1&63]
   255  	r1 = r1 - c.k[r0&63]
   256  	r0 = r0 - c.k[r3&63]
   257  
   258  	for j >= 0 {
   259  		// unmix r3
   260  		r3 = rotl16(r3, 16-5)
   261  		r3 = r3 - c.k[j] - (r2 & r1) - ((^r2) & r0)
   262  		j--
   263  
   264  		// unmix r2
   265  		r2 = rotl16(r2, 16-3)
   266  		r2 = r2 - c.k[j] - (r1 & r0) - ((^r1) & r3)
   267  		j--
   268  
   269  		// unmix r1
   270  		r1 = rotl16(r1, 16-2)
   271  		r1 = r1 - c.k[j] - (r0 & r3) - ((^r0) & r2)
   272  		j--
   273  
   274  		// unmix r0
   275  		r0 = rotl16(r0, 16-1)
   276  		r0 = r0 - c.k[j] - (r3 & r2) - ((^r3) & r1)
   277  		j--
   278  	}
   279  
   280  	binary.LittleEndian.PutUint16(dst[0:], r0)
   281  	binary.LittleEndian.PutUint16(dst[2:], r1)
   282  	binary.LittleEndian.PutUint16(dst[4:], r2)
   283  	binary.LittleEndian.PutUint16(dst[6:], r3)
   284  }