Web App Cryptology a Study in Failure
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GPU-Based Password Cracking on the Security of Password Hashing Schemes Regarding Advances in Graphics Processing Units
Radboud University Nijmegen Faculty of Science Kerckhoffs Institute Master of Science Thesis GPU-based Password Cracking On the Security of Password Hashing Schemes regarding Advances in Graphics Processing Units by Martijn Sprengers [email protected] Supervisors: Dr. L. Batina (Radboud University Nijmegen) Ir. S. Hegt (KPMG IT Advisory) Ir. P. Ceelen (KPMG IT Advisory) Thesis number: 646 Final Version Abstract Since users rely on passwords to authenticate themselves to computer systems, ad- versaries attempt to recover those passwords. To prevent such a recovery, various password hashing schemes can be used to store passwords securely. However, recent advances in the graphics processing unit (GPU) hardware challenge the way we have to look at secure password storage. GPU's have proven to be suitable for crypto- graphic operations and provide a significant speedup in performance compared to traditional central processing units (CPU's). This research focuses on the security requirements and properties of prevalent pass- word hashing schemes. Moreover, we present a proof of concept that launches an exhaustive search attack on the MD5-crypt password hashing scheme using modern GPU's. We show that it is possible to achieve a performance of 880 000 hashes per second, using different optimization techniques. Therefore our implementation, executed on a typical GPU, is more than 30 times faster than equally priced CPU hardware. With this performance increase, `complex' passwords with a length of 8 characters are now becoming feasible to crack. In addition, we show that between 50% and 80% of the passwords in a leaked database could be recovered within 2 months of computation time on one Nvidia GeForce 295 GTX. -
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms Levent Ertaul, Manpreet Kaur, Venkata Arun Kumar R Gudise CSU East Bay, Hayward, CA, USA. [email protected], [email protected], [email protected] Abstract- With the increase in mobile wireless or data lookup. Whereas, Cryptographic hash functions are technologies, security breaches are also increasing. It has used for building blocks for HMACs which provides become critical to safeguard our sensitive information message authentication. They ensure integrity of the data from the wrongdoers. So, having strong password is that is transmitted. Collision free hash function is the one pivotal. As almost every website needs you to login and which can never have same hashes of different output. If a create a password, it’s tempting to use same password and b are inputs such that H (a) =H (b), and a ≠ b. for numerous websites like banks, shopping and social User chosen passwords shall not be used directly as networking websites. This way we are making our cryptographic keys as they have low entropy and information easily accessible to hackers. Hence, we need randomness properties [2].Password is the secret value from a strong application for password security and which the cryptographic key can be generated. Figure 1 management. In this paper, we are going to compare the shows the statics of increasing cybercrime every year. Hence performance of 3 key derivation algorithms, namely, there is a need for strong key generation algorithms which PBKDF2 (Password Based Key Derivation Function), can generate the keys which are nearly impossible for the Bcrypt and Scrypt. -
Speeding up Linux Disk Encryption Ignat Korchagin @Ignatkn $ Whoami
Speeding Up Linux Disk Encryption Ignat Korchagin @ignatkn $ whoami ● Performance and security at Cloudflare ● Passionate about security and crypto ● Enjoy low level programming @ignatkn Encrypting data at rest The storage stack applications @ignatkn The storage stack applications filesystems @ignatkn The storage stack applications filesystems block subsystem @ignatkn The storage stack applications filesystems block subsystem storage hardware @ignatkn Encryption at rest layers applications filesystems block subsystem SED, OPAL storage hardware @ignatkn Encryption at rest layers applications filesystems LUKS/dm-crypt, BitLocker, FileVault block subsystem SED, OPAL storage hardware @ignatkn Encryption at rest layers applications ecryptfs, ext4 encryption or fscrypt filesystems LUKS/dm-crypt, BitLocker, FileVault block subsystem SED, OPAL storage hardware @ignatkn Encryption at rest layers DBMS, PGP, OpenSSL, Themis applications ecryptfs, ext4 encryption or fscrypt filesystems LUKS/dm-crypt, BitLocker, FileVault block subsystem SED, OPAL storage hardware @ignatkn Storage hardware encryption Pros: ● it’s there ● little configuration needed ● fully transparent to applications ● usually faster than other layers @ignatkn Storage hardware encryption Pros: ● it’s there ● little configuration needed ● fully transparent to applications ● usually faster than other layers Cons: ● no visibility into the implementation ● no auditability ● sometimes poor security https://support.microsoft.com/en-us/help/4516071/windows-10-update-kb4516071 @ignatkn Block -
Passwords, Hashes, and Cracks, Oh My! How Mac OS X Implements Password Authentication Dave Dribin “Why Should I Care?”
Passwords, Hashes, and Cracks, Oh My! How Mac OS X Implements Password Authentication Dave Dribin “Why Should I Care?” • Application Developer • System Administrator • End User Authentication • Authentication is the process of attempting to verify a user’s identity • Passwords authenticate using a “shared secret” History • Mac OS X based on NeXTSTEP • NeXTSTEP Unix on top of Mach • Unix developed by AT&T Bell Labs on DEC PDP-11 • Unix based on mainframe time-sharing systems UNIX Time-Sharing System Version 1 • Released in 1971 • First release of Unix as we know it • Plaintext passwords Plaintext Problems “Perhaps the most memorable [example] occurred in the early 60’s when a system administrator on the CTSS system at MIT was editing the password file and another system administrator was editing the daily message that is printed on everyone’s terminal on login. Due to a software design error, the temporary editor files of the two users were interchanged and thus, for a time, the password file was printed on every terminal when it was logged in.” -- Robert Morris and Ken Thompson, April 3,1978 Unix Versions 3, 4, 5, 6 • Released 1973 through 1975 • Encrypted Password • Password file is readable by all NAME passwd -- password file DESCRIPTION passwd contains for each user the following in- formation: name (login name, contains no upper case) encrypted password numerical user ID GCOS job number and box number initial working directory program to use as Shell This is an ASCII file. Each field within each user's entry is separated from the next by a colon. -
Forgery and Key Recovery Attacks for Calico
Forgery and Key Recovery Attacks for Calico Christoph Dobraunig, Maria Eichlseder, Florian Mendel, Martin Schl¨affer Institute for Applied Information Processing and Communications Graz University of Technology Inffeldgasse 16a, A-8010 Graz, Austria April 1, 2014 1 Calico v8 Calico [3] is an authenticated encryption design submitted to the CAESAR competition by Christopher Taylor. In Calico v8 in reference mode, ChaCha-14 and SipHash-2-4 work together in an Encrypt-then-MAC scheme. For this purpose, the key is split into a Cipher Key KC and a MAC Key KM . The plaintext is encrypted with ChaCha under the Cipher Key to a ciphertext with the same length as the plaintext. Then, the tag is calculated as the SipHash MAC of the concatenated ciphertext and associated data. The key used for SipHash is generated by xoring the nonce to the (lower, least significant part of the) MAC Key: (C; T ) = EncCalico(KC k KM ; N; A; P ); where k is concatenation, and with ⊕ denoting xor, the ciphertext and tag are calculated vi C = EncChaCha-14(KC ; N; P ) T = MACSipHash-2-4(KM ⊕ N; C k A): Here, A; P; C denote associated data, plaintext and ciphertext, respectively, all of arbitrary length. T is the 64-bit tag, N the 64-bit nonce, and the 384-bit key K is split into a 256-bit encryption and 128-bit authentication part, K = KC k KM . 2 Missing Domain Separation As shown above, the tag is calculated over the concatenation C k A of ciphertext and asso- ciated data. Due to the missing domain separation between ciphertext and associated data in the generation of the tag, the following attack is feasible. -
CMSC 426/626 - Computer Security Fall 2014
Authentication and Passwords CMSC 426/626 - Computer Security Fall 2014 Outline • Types of authentication • Vulnerabilities of password authentication • Linux password authentication • Windows Password authentication • Cracking techniques Goals of Authentication • Identification - provide a claimed identity to the system. • Verification - establish validity of the provided identity. We’re not talking about message authentication, e.g. the use of digital signatures. Means of Authentication • Something you know, e.g. password • Something you have, e.g. USB dongle or Common Access Card (CAC) • Something you are, e.g. fingerprint • Something you do, e.g. hand writing Password-Based Authentication • User provides identity and password; system verifies that the password is correct for the given identity. • Identity determines access and privileges. • Identity can be used for Discretionary Access Control, e.g. to give another user access to a file. Password Hashing Password • System stores hash of the user password, not the plain text password. Hash Algorithm • Commonly used technique, e.g. UNIX password hashing. Password Hash Password Vulnerabilities Assume the authentication system stores hashed passwords. There are eight attack strategies. • Off-line Dictionary Attack - get hold of the password file, test a collection (dictionary) of possible passwords. ‣ Most systems protect the password file, but attackers sometimes get hold of one. • Specific Account Attack - given a specific user account, try popular passwords. ‣ Most systems use lockout mechanisms to make these attacks difficult. • Popular Password Attack - given a popular password, try it on multiple accounts. ‣ Harder to defend against - have to look for patterns in failed access attempts. • Targeted Password Guessing - use what you know about a user to intelligently guess their password. -
How to Handle Rainbow Tables with External Memory
How to Handle Rainbow Tables with External Memory Gildas Avoine1;2;5, Xavier Carpent3, Barbara Kordy1;5, and Florent Tardif4;5 1 INSA Rennes, France 2 Institut Universitaire de France, France 3 University of California, Irvine, USA 4 University of Rennes 1, France 5 IRISA, UMR 6074, France [email protected] Abstract. A cryptanalytic time-memory trade-off is a technique that aims to reduce the time needed to perform an exhaustive search. Such a technique requires large-scale precomputation that is performed once for all and whose result is stored in a fast-access internal memory. When the considered cryptographic problem is overwhelmingly-sized, using an ex- ternal memory is eventually needed, though. In this paper, we consider the rainbow tables { the most widely spread version of time-memory trade-offs. The objective of our work is to analyze the relevance of storing the precomputed data on an external memory (SSD and HDD) possibly mingled with an internal one (RAM). We provide an analytical evalua- tion of the performance, followed by an experimental validation, and we state that using SSD or HDD is fully suited to practical cases, which are identified. Keywords: time memory trade-off, rainbow tables, external memory 1 Introduction A cryptanalytic time-memory trade-off (TMTO) is a technique introduced by Martin Hellman in 1980 [14] to reduce the time needed to perform an exhaustive search. The key-point of the technique resides in the precomputation of tables that are then used to speed up the attack itself. Given that the precomputation phase is much more expensive than an exhaustive search, a TMTO makes sense in a few scenarios, e.g., when the adversary has plenty of time for preparing the attack while she has a very little time to perform it, the adversary must repeat the attack many times, or the adversary is not powerful enough to carry out an exhaustive search but she can download precomputed tables. -
Cryptography As an Operating System Service: a Case Study
Cryptography As An Operating System Service: A Case Study ANGELOS D. KEROMYTIS Columbia University JASON L. WRIGHT and THEO DE RAADT OpenBSD Project and MATTHEW BURNSIDE Columbia University Cryptographic transformations are a fundamental building block in many security applications and protocols. To improve performance, several vendors market hardware accelerator cards. However, until now no operating system provided a mechanism that allowed both uniform and efficient use of this new type of resource. We present the OpenBSD Cryptographic Framework (OCF), a service virtualization layer im- plemented inside the operating system kernel, that provides uniform access to accelerator function- ality by hiding card-specific details behind a carefully designed API. We evaluate the impact of the OCF in a variety of benchmarks, measuring overall system performance, application throughput and latency, and aggregate throughput when multiple applications make use of it. We conclude that the OCF is extremely efficient in utilizing cryptographic accelerator func- tionality, attaining 95% of the theoretical peak device performance and over 800 Mbps aggregate throughput using 3DES. We believe that this validates our decision to opt for ease of use by applica- tions and kernel components through a uniform API and for seamless support for new accelerators. We are grateful to Global Technologies Group, Inc. for providing us with two XL-Crypt (Hifn 7811) boards, one Hifn 6500 reference board, and one Hifn 7814 reference board. We are also grateful to Network Security Technologies, Inc. for providing us with two Hifn 7751 boards, one Broadcom 5820 board, and two Broadcom 5805 boards. In addition, Network Security Technologies funded part of the original development of the device-support software. -
Permissions and Ownership
Getting Started with Linux: Novell’s Guide to CompTIA’s Linux+ Objective 1 Understand User and Group Configuration Files Information on users and groups on a Linux system is kept in the following files: ■ /etc/passwd ■ /etc/shadow ■ /etc/group Whenever possible, you should not modify these files with an editor. Instead, use the Security and Users modules in YaST or the command line tools described in the next objective, “Manage User Accounts and Groups from the Command Line” on 7-12. Modifying these files with an editor can lead to errors (especially in /etc/shadow), such as a user—including the user root—no longer being able to log in. To ensure consistency of these files, you need to understand how to ■ Check /etc/passwd and /etc/shadow ■ Convert Passwords to and from Shadow /etc/passwd The file /etc/passwd stores information for each user. In the past, UNIX and Linux users were handled in a single file: /etc/passwd. The user name, the UID, the home directory, the standard shell, and the encrypted password were all stored in this file. The password was encrypted using the function crypt (man 3 crypt). In principle, the plain text password could not be deciphered from the encrypted password. 7-2 Version 2 Use the Command Line Interface to Administer the System However, there are programs (such as john) that use dictionaries to encrypt various passwords with crypt, and then compare the results with the entries in the file /etc/passwd. With the calculation power of modern computers, simple passwords can be “guessed” within minutes. -
Securing Audio Using AES-Based Authenticated Encryption with Python
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 9 August 2021 doi:10.20944/preprints202108.0185.v1 Article Securing Audio Using AES-based Authenticated Encryption with Python Jessy Ayala 1 1 New York University, Tandon School of Engineering; [email protected] Featured Application: Securing communication of audio files utilizing symmetric authenticated encryption. Abstract: The focus of this research is to analyze the results of encrypting audio using various au- thenticated encryption algorithms implemented in the Python cryptography library for ensuring authenticity and confidentiality of the original contents. The Advanced Encryption Standard (AES) is used as the underlying cryptographic primitive in conjunction with various modes including Gal- ois Counter Mode (GCM), Counter with Cipher Block Chaining Message Authentication Code (CCM), and Cipher Block Chaining (CBC) with Keyed-Hashing for encrypting a relatively small audio file. The resulting encrypted audio shows similarity in the variance when encrypting using AES-GCM and AES-CCM. There is a noticeable reduction in variance of the performed encodings and an increase in the amount of time it takes to encrypt and decrypt the same audio file using AES- CBC with Keyed-Hashing. In addition, the corresponding encrypted using this mode audio spans a longer duration. As a result, AES should either have GCM or CCM for an efficient and reliable authenticated encryption integration within a workflow. Keywords: AES; Audio analysis; Authenticated encryption; Cryptography; Python 1. Introduction Cryptography is used worldwide for adhering to the security CIA triad: confidenti- ality, integrity, and availability. In an environment where mobile devices have become ubiquitous, voice messages are more common than one may think. -
Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms
66 Int'l Conf. Wireless Networks | ICWN'16 | Implementation and Performance Analysis of PBKDF2, Bcrypt, Scrypt Algorithms Levent Ertaul, Manpreet Kaur, Venkata Arun Kumar R Gudise CSU East Bay, Hayward, CA, USA. [email protected], [email protected], [email protected] Abstract- With the increase in mobile wireless or data lookup. Whereas, Cryptographic hash functions are technologies, security breaches are also increasing. It has used for building blocks for HMACs which provides become critical to safeguard our sensitive information message authentication. They ensure integrity of the data from the wrongdoers. So, having strong password is that is transmitted. Collision free hash function is the one pivotal. As almost every website needs you to login and which can never have same hashes of different output. If a create a password, it’s tempting to use same password and b are inputs such that H (a) =H (b), and a b. for numerous websites like banks, shopping and social User chosen passwords shall not be used directly as networking websites. This way we are making our cryptographic keys as they have low entropy and information easily accessible to hackers. Hence, we need randomness properties [2].Password is the secret value from a strong application for password security and which the cryptographic key can be generated. Figure 1 management. In this paper, we are going to compare the shows the statics of increasing cybercrime every year. Hence performance of 3 key derivation algorithms, namely, there is a need for strong key generation algorithms which PBKDF2 (Password Based Key Derivation Function), can generate the keys which are nearly impossible for the Bcrypt and Scrypt. -
Optimizing Authenticated Encryption Algorithms
Masaryk University Faculty of Informatics Optimizing authenticated encryption algorithms Master’s Thesis Ondrej Mosnáček Brno, Fall 2017 Masaryk University Faculty of Informatics Optimizing authenticated encryption algorithms Master’s Thesis Ondrej Mosnáček Brno, Fall 2017 This is where a copy of the official signed thesis assignment and a copy ofthe Statement of an Author is located in the printed version of the document. Declaration Hereby I declare that this paper is my original authorial work, which I have worked out on my own. All sources, references, and literature used or excerpted during elaboration of this work are properly cited and listed in complete reference to the due source. Ondrej Mosnáček Advisor: Ing. Milan Brož i Acknowledgement I would like to thank my advisor, Milan Brož, for his guidance, pa- tience, and helpful feedback and advice. Also, I would like to thank my girlfriend Ludmila, my family, and my friends for their support and kind words of encouragement. If I had more time, I would have written a shorter letter. — Blaise Pascal iii Abstract In this thesis, we look at authenticated encryption with associated data (AEAD), which is a cryptographic scheme that provides both confidentiality and integrity of messages within a single operation. We look at various existing and proposed AEAD algorithms and compare them both in terms of security and performance. We take a closer look at three selected candidate families of algorithms from the CAESAR competition. Then we discuss common facilities provided by the two most com- mon CPU architectures – x86 and ARM – that can be used to implement cryptographic algorithms efficiently.