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  1. OASIS Open Document Format for Office Applications (OpenDocument) TC
  2. OFFICE-2723

ODF 1.2 Part 3 3.4.2(3) Blowfish CFB Frame Size Not Specified

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    Details

    • Type: Bug
    • Status: Applied
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: ODF 1.2 CD 05
    • Fix Version/s: ODF 1.2 CD 06
    • Component/s: Packaging, Part 2 (Packages) [1.2: 3], Security
    • Labels:
      None
    • Environment:

      This issue applies to all versions of ODF since ODF 1.0. The specific section and wording is that of ODF 1.2 Part 3 CD01-rev08 (and the approved form, ODF 1.2 CD05 Part 3).

    • Proposal:
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      1. in the last sentence of 3.4.2, change the phrase "Blowfish algorithm in cipher feedback (CFB) mode" to "Blowfish algorithm in 8-bit cipher feedback (8-bit CFB) mode".

      2. Alternatively, if 8-bit CFB is not used in the current implementations, specify (1) what the frame size is, (2) how any padding for any partial frame is handled at the end and (3a) what is done to make the ciphertext be the same size as the plaintext if that is the case or (3b) how the exact-size plaintext is recovered whenever the ciphertext is not the same size.

      Show
      1. in the last sentence of 3.4.2, change the phrase "Blowfish algorithm in cipher feedback (CFB) mode" to "Blowfish algorithm in 8-bit cipher feedback (8-bit CFB) mode". 2. Alternatively, if 8-bit CFB is not used in the current implementations, specify (1) what the frame size is, (2) how any padding for any partial frame is handled at the end and (3a) what is done to make the ciphertext be the same size as the plaintext if that is the case or (3b) how the exact-size plaintext is recovered whenever the ciphertext is not the same size.
    • Resolution:
      Hide

      1. in the last sentence of 3.4.2, change the phrase "Blowfish algorithm in cipher feedback (CFB) mode" to "Blowfish algorithm in 8-bit cipher feedback (8-bit CFB) mode".

      2. In section 4.8.1 manifest:algorithm-name, change the definition for the "Blowfish CFB:" from
      """
      The Blowfish algorithm in CFB mode"
      """
      to
      """
      The Blowfish algorithm in 8-bit CFB mode.
      """

      Show
      1. in the last sentence of 3.4.2, change the phrase "Blowfish algorithm in cipher feedback (CFB) mode" to "Blowfish algorithm in 8-bit cipher feedback (8-bit CFB) mode". 2. In section 4.8.1 manifest:algorithm-name, change the definition for the "Blowfish CFB:" from """ The Blowfish algorithm in CFB mode" """ to """ The Blowfish algorithm in 8-bit CFB mode. """

      Description

      In Part 3 section 3.4.2(3), it is stated that encryption (and the corresponding decryption) use "the Blowfish algorithm in cipher feedback (CFB) mode (see [Blowfish])."

      CFB mode is described in section 9.6 Cipher-Feedback Mode of [Blowfish]. CFB mode provides for encryption in different frame sizes up to the block size of the encryption algorithm. In the case of Blowfish, the block size is 64 bits. Different CFB frame sizes (e.g., 1, 8, 16, and 32 bits) do not result in the same ciphertext.

      To decrypt a file encrypted with CFB, it is necessary to know the frame size that was used for the encryption. If the frame size is not one that exactly divides 8, it must also be know how the last octets of the ciphertext are produced such that the ciphertext is of the same size as the original plaintext or how the exact plaintext size is to be recovered.

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            • Assignee:
              orcmid Dennis Hamilton (Inactive)
              Reporter:
              orcmid Dennis Hamilton (Inactive)
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              • Created:
                Updated:
                Resolved: