G. Cattaneo, L. Catuogno, A. D. Sorbo, and P. Persiano, "The design and implementation of a transparent cryptographic file system for Unix," in Proc. USENIX Annual Technical Conference 2001.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... sledgehammer denial of service attack, in which an administrator deletes all files. File Sharing. The ability to share files amongst users is essential in a network file system. SiRiUS users must be able to share a file easily with other users of the system. Existing cryptographic file systems [2, 35, 1, 7, 13] limit their own usefulness because they either provide very coarse sharing at the directory or file system level or fail to distinguish between read and write access. File systems that do provide per file sharing [24, 19, 29, 18] rely on a trusted authentication mechanism residing on the file ....

....to CFS but also supports file integrity and group sharing of files. However, CSFS does not provide read write access controls. CSFS also relies on a highly trusted group database server that determines group membership (and hence access control) The Transparent Cryptographic File System (TCFS) [7] is another extension of CFS. Each user in TCFS possesses a master key which is used to protect unique file keys. TCFS has a group threshold sharing scheme that require a certain number of active group members before group shared files become accessible. Apart from this scheme, no other form of ....

G. Cattaneo, L. Catuogno, A. D. Sorbo, and P. Persiano. The design and implementation of a transparent cryptographic file system for UNIX. In Proceedings of USENIX Technical Conference, FREENIX Track. USENIX, June 2001.

....data stored in memory by appending the data blocks with a MAC of itself. To prevent an adversary from copying blocks from one memory address to another, the block s address is included in the MAC. The Protected File System (PFS) SHS01] and the Transparent Cryptographic File System (TCFS) CCSP01] use similar integrity protection mechanisms. As described in Section 1.2, this approach is vulnerable to replay attacks. For example, XOM will not notice if stores to memory are never performed (except when memory is first initialized) The Byzantine fault tolerant file system [CL99, CL00] is ....

G. Cattaneo, L. Catuogno, A. Del Sorbo, and P. Persiano. The design and implementation of a transparent cryptographic file system for unix. In Proceedings of the FREENIX Track: USENIX Annual Technical Conference, Boston, MA, 2001.

....all directories and their contents. The original work in this area is the Cryptographic File System (CFS) 5] which used a single key to encrypt an entire directory of files and depended on the underlying file system for authorization of writes. Later variants on this approach include TCFS [8], which uses a lockbox to protect only the keys, and Cryptfs [51] Cepheus [13] uses group managed lockboxes with a centralized key server and authorization at the trusted server. SNAD [35] also uses lockboxes and introduces several alternatives for verifying writes. The SiRiUS file system layers ....

G. Cattaneo, G. Persiano, A. Del Sorbo, A. Cozzolino, E. Mauriello, and R. Pisapia. Design and implementation of a transparent cryptographic file system for UNIX. Technical report, University of Salerno, 1997.

....of a write ahead file system [20] PFS validates blocks against a volatile array of one way hash values. Cattaneo et al. implemented Transparent Cryptographic File System, TCFS, which validates file blocks using Hash based Message Authentication Codes (HMACs) 14] that are embedded in the blocks [4]. However, both PFS and TCFS do not detect replays of old blocks. Mazieres and Shasha described a design of Secure Untrusted Data Repository, SUNDR, which has a storage organization similar to SFSRO, but stores the root hash in a secure location (presumably a client) 13] Unlike GnatDb, the main ....

G. Cattaneo, L. Catuogno, A. Del Sorbo, and P. Persiano. The design and implementation of a transparent cryptographic file system for UNIX. In Proceedings of the FREENIX Track: USENIX Annual Technical Conference, June 2001. Boston, MA.

....performance can be a significant factor. Since Cryptfs is a stackable file system, we included figures for Wrapfs and for Lofs, to be used as a base for evaluating the cost of stacking. When using lofs, Wrapfs, or Cryptfs, we mounted them over a local disk based file system. CFS[3] and TCFS[4] are two encryption file systems based on NFS, so we also included the performance of native NFS. All NFS mounts used the local host as both server and client (i.e. mounting localhost: path on mnt) and used protocol version 2 over a UDP transport, with a user space NFS server . CFS was ....

....a secure directory and choose the encryption algorithm and key to use. A wide choice of ciphers is available and great care was taken to ensure a high degree of security. CFS s performance is limited by the number of context switches that must be performed and the encryption algorithm used. TCFS[4] is a modified client side NFS kernel module that communicates with a remote NFS server. TCFS is available only for Linux systems, and both client and server must run on Linux. TCFS allows finer grained control over encryption; individual files or directories can be encrypted by turning on or off ....

G. Cattaneo and G. Persiano. Design and Implementation of a Transparent Cryptographic File System for Unix. Unpublished Technical Report. Dip. Informatica ed Appl, Universita di 9 Salerno, 8 July 1997. Available via ftp in ftp://edugw. dia.unisa.it/pub/tcfs/docs/tcfs.ps.gz.

....a secure directory and choose the encryption algorithm and key to use. A wide choice of ciphers is available and great care was taken to ensure a high degree of security. CFS s performance is limited by the number of context switches that must be performed and the encryption algorithm used. TCFS[4] is a modified client side NFS kernel module that communicates with a remote NFS server. TCFS is available only for Linux systems, and both client and server must run on Linux. TCFS allows finer grained control over encryption individual files or directories can be encrypted by turning on or off ....

G. Cattaneo and G. Persiano. Design and Implementation of a Transparent Cryptographic File System for Unix. Unpublished Technical Report. Dip. Informatica ed Appl, Universita di Salerno, 8 July 1997. Available via ftp in ftp://edu-gw.dia.unisa.it/pub/tcfs/docs/tcfs.ps.gz.

....but not both. For example, CFS [3] encrypts data, but does not easily permit authentication of data or sharing with other users. Systems such as SFS RO [18] and NASD [12, 13] use encryption to provide network security and authentication, but store data in the clear. Recently, systems such as TCFS [6] and SUNDR [19] have incorporated both authentication and encryption, but at a relatively high penalty to performance. We have developed a security system for networkattached storage that relies upon strong cryptography to protect data stored in a distributed storage system. Our system stores and ....

....that the server has not maliciously altered the data. In addition, CFS does not discuss mechanisms for distributing keys among users for sharing files. A more recent cryptographic file system, Cryptfs [27] works in a similar way and has similar sharing and authentication issues. Recently, TCFS [6] has provided strong security and authentication for file system users. However, TCFS is relatively slow, reducing file system performance by more than 50 . The design of a trusted database system such as Trusted DataBase (TDB) 17] could be adapted to file systems; however, TDB is not easily ....

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G. Cattaneo, L. Catuogno, A. D. Sorbo, and P. Persiano. The design and implementation of a transparent cryptographic file system for UNIX. In Proceedings of the Freenix Track: 2001.

....prevent unintentional transfer of sensitive data to unencrypted file systems, where it would be stored in plaintext. 1 Introduction There exist several projects for the Unix operating system that offer transparent cryptographic protection for files or complete file systems (e.g. CFS [1] TCFS [2], ppdd [3] loopback device encryption extension) All these solutions suffer from two major shortcomings: 1. Only the owner of the data has access to the encrypted files. To share such files with other users, the owner needs to give the encryption key to every user who should be able to access ....

G. Cattaneo and G. Persiano. Design and Implementation of a Transparent Cryptographic Filesystem for Unix. Unpublished Technical Report, July 1997 ftp://edu-gw.dia.unisa.it/pub/tcfs/ docs/tcfs.ps.gz

....hashes are written to the same write ahead log as the meta data updates. PFS does not provide protection against replay attacks. SUNDR [11] is a network file system designed to run on untrusted servers. It supports both data encryption and verification using hash trees similar to SFS RO. TCSF [4] also supports both encryption and verification, but calculates a message digest on each block and cannot detect replay attacks. The primary benefit of a secure file system is that it exports the familiar file system interface. However, it may not be appropriate for DRM systems that require ....

G. Cattaneo, L. Catuogno, A. Del Sorbo, and P. Persiano. The design and implementation of a transparent cryptographic file system for unix. In Proceedings of the FREENIX Track: USENIX Annual Technical Conference, June 2001. Boston, MA.

....CFS to be more efficient by building it as a stackable file system rather than a user level server. It attempts to make the system more resilient to attacks due to corruption of individual users by using session IDs and user IDs to index into the key table, rather than using only usernames. TCFS [Cattaneo97, Cattaneo01] uses a lockbox to store a single key (rather than per directory keys) and encrypts only file data and file names; directory structures and other metadata are left un encrypted. Beyond the implementation differences and varying key granularity, CryptFS, TCFS, and CFS are identical with respect to ....

G. Cattaneo, L. Catuogno, A. Del Sorbo and P. Persiano. The Design and Implementation of a Transparent Cryptographic File System for UNIX. FREENIX

....already stored in encrypted form. Similarly, if written data is encrypted before it leaves the client and is stored encrypted, the server eliminates any decryption work. Storing data in encrypted form was originally proposed in Blaze s Cryptographic File System (CFS) and expanded in later systems [Blaze93, Cattaneo97, Zadok98, Hughes99], where it is used for a different purpose to protect data from untrusted servers. If data is stored on the server in encrypted form it is protected from leaking by the server (who does not know the key) and there is no need to encrypt data again when it is sent on the network. Encryption is ....

....CFS to be more efficient by building it as a stackable file system rather than a user level server. It attempts to make the system more resilient to attacks due to corruption of individual users by using session IDs and user IDs to index into the key table, rather than using only usernames. TCFS [Cattaneo97, Cattaneo01] uses a lockbox to store a single key (rather than per directory keys) and encrypts only file data and file names; directory structures and other metadata are left un encrypted. Beyond the implementation differences and varying key granularity, CryptFS, TCFS, and CFS are identical with respect to ....

G. Cattaneo, G. Persiano, A. Del Sorbo, A. Cozzolino, E. Mauriello and R. Pisapia. Design and implementation of a transparent cryptographic file system for UNIX. Technical Report, University of Salerno, 1997.

....form. Similarly, if write data is encrypted before it leaves the client and is stored encrypted, the server eliminates any decryption work. As it happens, such storing of data in encrypted form was originally proposed in Blaze s Cryptographic File System (CFS) and expanded in later systems [Blaze93, Cattaneo97, Zadok98, Hughes99], where it is used for a different purpose to protect data from untrusted servers. If data is stored on the server in encrypted form it is protected from leaking by the server (who does not know the key) and there is no need to encrypt data again when it is sent on the network. Encryption is ....

G. Cattaneo, G. Persiano, A. Del Sorbo, A. Cozzolino, E. Mauriello and R. Pisapia. Design and implementation of a transparent cryptographic file system for UNIX. Technical Report, University of Salerno, 1997.

....the le system level. Users associate a cryptographic key with the directories they wish to protect. Files in these directories are transparently encrypted and decrypted with the speci ed key without further user intervention. Gattaneo and Persiano proposed the transparent cryptographic le system [4]. The TCFS(Transparent Cryptographic File System) provides almost transparent access to the encrypted le system. The login password is used for the user authentication. Once the user logins the system successfully, the access to the encrypted le system requires no more password. The TCFS uses ....

G. Cattaneo and G. Persiano, Design and Implementation of a Transparent Cryptographic Filesystem for Unix. Unpublished Technical Report, ftp://edu-gw.dia.unisa.it/pub/tcfs/docs/tcfs.ps.gz, July 1997.

....(5) The 6 kernel completes the read command by delivering the data to the user process at (6) This results in two additional context switches to the kernel than a normal read. There are many examples in the literature of file systems developed as user processes; these include CFS [4] and TCFS [5]. Please refer to section 2 for more a more detailed evaluation of these file systems. All of the file systems that are implemented as a user level process are susceptible to a major performance problem. The use of a user level process requires additional context switches that increase the ....

G. Cattaneo and G. Persiano, "Design and Implementation of a transparent cryptographic file system for Unix," Universita de Salerno, Salerno July 1997.

....cryptographic storage file system uses this library[42] Consult the SFS documentation for further information on its use and implementation[13] 1.4. 3 Transparent Cryptographic File System The Transparent Cryptographic File System (TCFS) seeks to improve upon the security model set by CFS[7]. Several students and faculty developed TCFS at the Universita di Salerno in Italy during 1997. The early development was lead by G. Cattaneo, G. Persiano, A. Del Sorbo, A. Cozzolino, E. Mauriello, and R. Pisapia. New releases of TCFS appear on a regular basis. TCFS aims to o#er the feel of the ....

G. Cattaneo, G. Persiano, A. Del Sorbo, A. Cozzolino, E. Mauriello, and R. Pisapia. Design and Implementation of a Transparent Cryptographic File System for UNIX. http://tcfs.dia.unisa.it/, 1997. 79

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G. Cattaneo, L. Catuogno, A. D. Sorbo, and P. Persiano, "The design and implementation of a transparent cryptographic file system for Unix," in Proc. USENIX Annual Technical Conference 2001.

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G. Cattaneo, L. Catuogno, A. D. Sorbo, and P. Persiano. The design and implementation of a transparent cryptographic file system for unix. In Proceedings of the FREENIX Track: 2001.

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G. Cattaneo, L. Catuogno, A. Del Sorbo, P. Persiano. The Design and Implementation of a Transparent Cryptographic File System for UNIX. In USENIX Annual Technical Conference 2001, Freenix Track.

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G. Cattaneo, L. Catuogno, A. Del Sorbo, and P. Persiano. The Design and Implementation of a Transparent Cryptographic Filesystem for UNIX. In Proceedings of the Annual USENIX Technical Conference, FREENIX Track, pages 245--252, June 2001.

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G. Cattaneo and L. Catuogno and A. Del Sorbo and P. Persiano, The Design and Implementation of a Transparent Cryptographic Filesystem for UNIX, FREENIX, 2001.

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G. Cattaneo and G. Persiano. Design and implementation of a transparent cryptographic filesystem for Unix. Unpublished Technical Report, ftp://edu-gw.dia.unisa.it/pub/tcfs/docs/tcfs.ps.gz,, July 1997.

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G. Cattaneo and G. Persiano. Design and Implementation of a Transparent Cryptographic File System For Unix. Technical report, July 1997.

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G. Cattaneo, L. Catuogno, A. Del Sorbo, and P. Persiano. The Design and Implementation of a Transparent Cryptographic Filesystem for UNIX. In Proceedings of the Annual USENIX Technical Conference, FREENIX Track, pages 245--252, June 2001.

No context found.

G. Cattaneo, L. Catuogno, A. D. Sorbo and P. Persiano, The Design and Implementation of a Transparent Cryptographic Filesystem for UNIX. In Proceedings of the Freenix Track: USENIX Annual Technical Conference, 2001. pp. 199-212.

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G. Cattaneo, L. Catuogno, A. Del Sorbo, and P. Persiano. "Design and Implementation of a Transparent Cryptographic File System for Unix", Proceedings of the Freenix Track: 2001.

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