rfcrfc2040.txt

本程序为在linux下实现FTP传输文件的实现

ptv->cipher_length += numBytesOut;
    (void) RC5_CBC_Encrypt_Final (pAlg,
                    &(numBytesOut),
                    MAX_CIPHER_LENGTH - ptv->cipher_length,
                    &(ptv->cipher[ptv->cipher_length]));
    ptv->cipher_length += numBytesOut;
    bytes_to_hex (ptv->cipher, ptv->cipher_length,
                 ptv->ciphertext);
    RC5_Key_Destroy (pKey);
    RC5_CBC_Destroy (pAlg);
  }

  void show_results (ptv)
    test_vector *ptv;
  {
    if (ptv->padding_mode)
        printf ("RC5_CBC_Pad ");
    else
        printf ("RC5_CBC     ");
    printf ("R = %2d ", ptv->rounds);
    printf ("Key = %s ", ptv->keytext);
    printf ("IV = %s ", ptv->ivtext);
    printf ("P = %s ", ptv->plaintext);
    printf ("C = %s", ptv->ciphertext);
    printf ("\n");
  }

  int main(argc, argv)
    int argc;
    char *argv[];
  {
    test_vector tv;
    test_vector *ptv = &tv;

    show_banner();
    while (get_test_vector(ptv))  {
        run_test(ptv);
        show_results(ptv);
    }
    return (0);
  }

9.2  测试向量
        下面的文本是前一节测试程序的输入文件。输出在下一节中给出。

  0 00 00                 0000000000000000 0000000000000000
  0 00 00                 0000000000000000 ffffffffffffffff
  0 00 00                 0000000000000001 0000000000000000
  0 00 00                 0000000000000000 0000000000000001
  0 00 00                 0102030405060708 1020304050607080
  0 01 11                 0000000000000000 0000000000000000
  0 02 00                 0000000000000000 0000000000000000
  0 02 00000000           0000000000000000 0000000000000000
  0 08 00                 0000000000000000 0000000000000000
  0 08 00                 0102030405060708 1020304050607080
  0 12 00                 0102030405060708 1020304050607080
  0 16 00                 0102030405060708 1020304050607080
  0 08 01020304           0000000000000000 ffffffffffffffff
  0 12 01020304           0000000000000000 ffffffffffffffff
  0 16 01020304           0000000000000000 ffffffffffffffff
  0 12 0102030405060708   0000000000000000 ffffffffffffffff
  0 08 0102030405060708   0102030405060708 1020304050607080
  0 12 0102030405060708   0102030405060708 1020304050607080
  0 16 0102030405060708   0102030405060708 1020304050607080
  0 08 01020304050607081020304050607080
                          0102030405060708 1020304050607080
  0 12 01020304050607081020304050607080
                          0102030405060708 1020304050607080
  0 16 01020304050607081020304050607080
                          0102030405060708 1020304050607080

  0 12 0102030405         0000000000000000 ffffffffffffffff
  0 08 0102030405         0000000000000000 ffffffffffffffff
  0 08 0102030405         7875dbf6738c6478 0808080808080808
  1 08 0102030405         0000000000000000 ffffffffffffffff

  0 08 0102030405         0000000000000000 0000000000000000
  0 08 0102030405         7cb3f1df34f94811 1122334455667701

  1 08 0102030405         0000000000000000
  ffffffffffffffff7875dbf6738c647811223344556677

9.3  测试结果
        下面的文本是测试程序运行于前一节给定输入的输出文本。
RC5 CBC 测试器。
每个输入行应该包含下面用空格号分隔的测试参数：
－填充模式标志。使用１表示RC5-CBC-Pad，其余用０表示。
－RC5的轮数。
－16进制的密钥。每字节两个字符像‘０１’。
－16进制的初始向量。必须是16进制的字节。
－16进制的明文字节。
到达文件末尾或格式错误终止测试器。

RC5_CBC     R =  0 Key = 00 IV = 0000000000000000
   P = 0000000000000000 C = 7a7bba4d79111d1e
  RC5_CBC     R =  0 Key = 00 IV = 0000000000000000
   P = ffffffffffffffff C = 797bba4d78111d1e
  RC5_CBC     R =  0 Key = 00 IV = 0000000000000001
   P = 0000000000000000 C = 7a7bba4d79111d1f
  RC5_CBC     R =  0 Key = 00 IV = 0000000000000000
   P = 0000000000000001 C = 7a7bba4d79111d1f
  RC5_CBC     R =  0 Key = 00 IV = 0102030405060708
   P = 1020304050607080 C = 8b9ded91ce7794a6
  RC5_CBC     R =  1 Key = 11 IV = 0000000000000000
   P = 0000000000000000 C = 2f759fe7ad86a378
  RC5_CBC     R =  2 Key = 00 IV = 0000000000000000
   P = 0000000000000000 C = dca2694bf40e0788
  RC5_CBC     R =  2 Key = 00000000 IV = 0000000000000000
   P = 0000000000000000 C = dca2694bf40e0788
  RC5_CBC     R =  8 Key = 00 IV = 0000000000000000
   P = 0000000000000000 C = dcfe098577eca5ff
  RC5_CBC     R =  8 Key = 00 IV = 0102030405060708
   P = 1020304050607080 C = 9646fb77638f9ca8
  RC5_CBC     R = 12 Key = 00 IV = 0102030405060708
   P = 1020304050607080 C = b2b3209db6594da4
  RC5_CBC     R = 16 Key = 00 IV = 0102030405060708
   P = 1020304050607080 C = 545f7f32a5fc3836
  RC5_CBC     R =  8 Key = 01020304 IV = 0000000000000000
   P = ffffffffffffffff C = 8285e7c1b5bc7402
  RC5_CBC     R = 12 Key = 01020304 IV = 0000000000000000
   P = ffffffffffffffff C = fc586f92f7080934
  RC5_CBC     R = 16 Key = 01020304 IV = 0000000000000000
   P = ffffffffffffffff C = cf270ef9717ff7c4
  RC5_CBC     R = 12 Key = 0102030405060708 IV = 0000000000000000
   P = ffffffffffffffff C = e493f1c1bb4d6e8c
RC5_CBC     R =  8 Key = 0102030405060708 IV = 0102030405060708
   P = 1020304050607080 C = 5c4c041e0f217ac3
  RC5_CBC     R = 12 Key = 0102030405060708 IV = 0102030405060708
   P = 1020304050607080 C = 921f12485373b4f7
  RC5_CBC     R = 16 Key = 0102030405060708 IV = 0102030405060708
   P = 1020304050607080 C = 5ba0ca6bbe7f5fad
  RC5_CBC     R =  8 Key = 01020304050607081020304050607080
   IV = 0102030405060708
   P = 1020304050607080 C = c533771cd0110e63
  RC5_CBC     R = 12 Key = 01020304050607081020304050607080
   IV = 0102030405060708
   P = 1020304050607080 C = 294ddb46b3278d60
  RC5_CBC     R = 16 Key = 01020304050607081020304050607080
   IV = 0102030405060708
   P = 1020304050607080 C = dad6bda9dfe8f7e8
  RC5_CBC     R = 12 Key = 0102030405 IV = 0000000000000000
   P = ffffffffffffffff C = 97e0787837ed317f
  RC5_CBC     R =  8 Key = 0102030405 IV = 0000000000000000
   P = ffffffffffffffff C = 7875dbf6738c6478
  RC5_CBC     R =  8 Key = 0102030405 IV = 7875dbf6738c6478
   P = 0808080808080808 C = 8f34c3c681c99695
  RC5_CBC_Pad R =  8 Key = 0102030405 IV = 0000000000000000
   P = ffffffffffffffff C = 7875dbf6738c64788f34c3c681c99695
  RC5_CBC     R =  8 Key = 0102030405 IV = 0000000000000000
   P = 0000000000000000 C = 7cb3f1df34f94811
  RC5_CBC     R =  8 Key = 0102030405 IV = 7cb3f1df34f94811
   P = 1122334455667701 C = 7fd1a023a5bba217
  RC5_CBC_Pad R =  8 Key = 0102030405 IV = 0000000000000000
   P = ffffffffffffffff7875dbf6738c647811223344556677
   C = 7875dbf6738c64787cb3f1df34f948117fd1a023a5bba217

10.安全考虑
        RC5密码相对来说是比较新的所以鉴定的评论仍在进行。然而，密码的简单结构使
它易于分析而且有希望更容易的评定它的的强度。迄今为止的评论是有前途的。
        早期的结果暗示12轮64位块大小的RC5将有足够的能力抗拒线性和差分密码分
析。128位的块版本还未像64位的块版本进行多次研究。但是明显的16轮是一个合适的最
小值。小于64位的块尺寸学术上的兴趣但是不应被用于密码安全。更大的安全可以通过增
加轮数获得其代价是减少密码的吞吐量。
        密钥的长度帮助决定密码对穷举攻击的抵抗力。一个128位的密钥长度应该几十年
的时间里为抗拒资金雄厚的对手的穷举攻击提供保护。12轮的RC5，密钥的建立时间和数据
加密时间对于所有长度小于832位的密钥来说都是相同的。因此没有因为不需要为了性能要
求而选择短密钥。对于大的密钥，因为用户的密钥表，L，将比扩展密钥表，S，长所以密钥
扩展的步骤会运行的比较慢。然而，加密时间将不会改变因此它只是一个轮数的函数。
        未了配合出口规则可能需要选择密钥只有40个未知位。进行这一步处理的简单方
式是选择一个简单的５个字节的密钥。这应该被避免因为对手可以容易的预计算密钥搜索信
息。另一个一般的机制是选择128位的密钥出版头88位。这个方法揭示了大量的通往用户
密钥表，L，的路径。且是否RC5密钥扩展表在这种情况下提供了足够的安全还未进行研究。
尽管它可能是好的。一个与40位密钥限制一致的一种保守的方法是选择128位的种子值，
出版这个种子的前88位，通过像MD5的散列函数运行整个种子值，使用这个散列函数的128
位的输出作为RC5的密钥。
        在有40位未知密钥和88位已知密钥的情况下，对于64位RC5块版本应该有12
轮或更高的轮数，否则增加给密钥的88位的值可能被丢失。
        密钥的生存期也是影响安全的关键。对于高安全的应用，任何64位块密码的密钥
应该在加密了2**32个块后被改变（2**64个块对于128位的块密码）。这将帮助防范线性
和差分密码分析。对于64位的块，这个规则将推荐在2**40个字节被加密后改变密钥。进
一步的讨论见Schneier应用密码学183页。

11. ASN.1标识符
        对于使用ASN.1描述的应用，有必要为这些与他们参数块格式相一致的密码定义算
法标识符。一个算法标识符的ASN.1的定义已经存在，以下列出作为参考。
AlgorithmIdentifier ::= SEQUENCE {
    algorithm    OBJECT IDENTIFIER,
    parameters   ANY DEFINED BY algorithm OPTIONAL
  }

  The values for the algorithm field are:

  RC5_CBC  OBJECT IDENTIFIER ::=
    { iso (1) member-body (2) US (840) rsadsi (113549)
      encryptionAlgorithm (3) RC5CBC (8) }

  RC5_CBC_Pad OBJECT IDENTIFIER ::=
  { iso (1) member-body (2) US (840) rsadsi (113549)
    encryptionAlgorithm (3) RC5CBCPAD (9) }

   The structure of the parameters field for these algorithms is given
   below.  NOTE: if the iv field is not included, then the
   initialization vector defaults to a block of zeros whose size depends
   on the blockSizeInBits field.

  RC5_CBC_Parameters ::= SEQUENCE {
    version           INTEGER (v1_0(16)),
    rounds            INTEGER (8..127),
    blockSizeInBits   INTEGER (64, 128),
    iv                OCTET STRING OPTIONAL
  }

12.参考
   [1] Kaliski, Burton S., and Yinqun Lisa Yin, "On Differential and
   Linear Cryptanalysis of the RC5 Encryption Algorithm", In Advances
   in Cryptology - Crypto '95, pages 171-184, Springer-Verlag, New
   York, 1995.

   [2] Rivest, Ronald L., "The RC5 Encryption Algorithm", In
   Proceedings of the Second International Workshop on Fast Software
   Encryption, pages 86-96, Leuven Belgium, December 1994.

   [3] Rivest, Ronald L., "RC5 Encryption Algorithm", In Dr. Dobbs
   Journal, number 226, pages 146-148, January 1995.

   [4] Rivest, Ronald L., "The MD5 Message-Digest Algorithm", RFC
   1321.

   [5] RSA Laboratories, "Public Key Cryptography Standards (PKCS)",
   RSA Data Security Inc.  See ftp.rsa.com.

   [6] Schneier, Bruce, "Applied Cryptography", Second Edition, John
   Wiley and Sons, New York, 1996.  Errata: on page 195, line 13, the
   reference number should be [402].

   [7] Business Software Alliance, Matt Blaze et al., "Minimum Key
   Length for Symmetric Ciphers to Provide Adequate Commercial
   Security", http://www.bsa.org/bsa/cryptologists.html.

   [8] RSA Data Security Inc., "RC5 Reference Code in C", See the web
   site: www.rsa.com, for availability.  Not available with the first
   draft of this document.

13.作者地址

   Robert W. Baldwin
   RSA Data Security, Inc.
   100 Marine Parkway
   Redwood City, CA 94065

   Phone: [phone]
   Fax:   [phone]
   EMail: [e-mail], or [e-mail]


   Ronald L. Rivest
   Massachusetts Institute of Technology
   Laboratory for Computer Science
   NE43-324
   545 Technology Square
   Cambridge, MA 02139-1986

   Phone: [phone]
   EMail: [e-mail]




RFC2040——The RC5, RC5-CBC, RC5-CBC-Pad, and RC5-CTS Algorithms
                                         RC5,RC5-CBC,RC5-CBC-PAD和RC5-CTS算法


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