• And When Your Goal Is Nearest Mac Os Catalina
• And When Your Goal Is Nearest Mac Os Download

Mar 04, 2021 • Filed to: Take Data Backup • Proven solutions

Cryptography is difficult and the cost of bugs typically so high that it's rarely a good idea to implement your own cryptography solution. Rely on the Security framework when you need cryptography in your app. Figure 1 Tools to enable secure interaction with users, data, and code. Always use the highest level API that meets your needs. There are tons of hidden features and shortcuts for Macs that Apple has built into macOS over the years, ranging from shortcuts to keyboard commands to other.

Issues like these are bound to exist when you are using an iMac. The good part is that you can easily get rid of them in no time. In this guide, you will get to know about the solutions for Mac migration assistant stuck or frozen while conducting your tasks. Furthermore, you will get to know all the possible reasons for this dilemma. Good knowledge will allow you to tackle it in the future is much easier. Lastly, you will have quick methods to solve the issue, and you can also utilize the time machine at the end. You just need to stick to the guide properly. Every method mentioned in the guide is applicable to this error.

Why Mac Migration Assistant Stuck or Frozen?

It is better to understand the reasons behind any trouble to solve it properly. Well, the case of Mac migration assistant suck or frozen usually occurs due to various reasons. There are no specific reasons which cause this issue. Yet, you can inevitably compare it to your scenario after studying the causes of this trouble. There are multiple scenarios of this issue. Sometimes Mac migration is stuck at the beginning of the process. In some cases, it is stuck in the middle with messages like; 15 hours are remaining. The most irritating scenario is when it is stuck in the end with a message that less than a minute remaining.

Source device disconnected accidentally is the prime cause behind this issue. However, poor network connection also leads a person to a situation where Mac migration is stuck. If not, corrupt files and hardware issues can also act as culprits behind the messages. Looking for a source, looking for applications and documents to transfer, looking for other computers or preparing transfer user documents, and many more.

How to Fix Mac Migration Assistant Stuck or Frozen?

You surely are aware of all the reasons behind this problem. Now, you need to know all possible solutions to this dilemma. As every problem comes with a solution, you just need to apply that to your situation. However, you will be given the solution to your problem while mentioning the cause behind it;

1 Try to use target disk mode on the old Mac

This is the first and foremost important method to follow. You can solve your issue by using target disk mode on the old Mac. Target disk mode is a boot mode that enables almost every Mac to act as an external hard drive for any other Mac. This is universal and very easy to set up. This is also the fastest method to move files between two Macs.

Almost every Mac attains the feature of target disk mode, and it is compatible with any latest Mac. Target disk mode is arranged into the Mac firmware; this is the reason that it is easy to set up. You can hold the T key button during the boot, or you can click a button in the startup disk preference pane to enable target disk mode. The Thunderbolt connection allows you to transfer files at the fastest speed. You can certainly utilize this method to solve your dilemma.

2 Unplug the ethernet cable from both machines and reinsert it

Suppose you think that the above tip is a lengthy one. You can try this one before trying the previous one. Sometimes, the silliest mistakes lead to problematic situations. Mac migration assistant can be stuck or frozen due to connectivity issues. You need to unplug the ethernet machine cable from both sides and insert it again. This might solve your problem as a large number of users have reported that this method has greatly helped them out. The process resumes, and synchronization resumes smoothly.

3 Try to migrate everything except Applications.

Applications acquire a large bulk of space and are not easily transferred from one computer to another, especially in iMac. This is the reason that you have to let go of your application and migrate all the other data. You can transfer all the data first and can reinstall the apps properly again. Users have reported that this method is the most convenient and effective.

4 Run a hardware diagnosis

Many people run hardware diagnoses to identify any problem in the hard drive. Corrupted or damaged hard drives can also lead to this situation. Make sure you have Apple Mac released after 2013 as they have Apple hardware test feature in them. You need to shut down your Mac and disconnect all the external devices like mouse, keyboard, speakers, display, any ethernet connection, or anything else. Once you have done that, you need to press the power button on your Mac and then immediately press and hold 'D' on the keyboard.

As prompt appears on the screen, release the 'D' key. Now, choose the desired language. You can also join a local WIFI connection. Furthermore, choose the option 'Perform extended testing', this checks every block of your Mac's memory. After choosing this option, select the 'Test' button. This process might take some time. If you have chosen extended testing, then you have to wait much more. Your Mac will be scanned. After the scan is completed, you will have a list of issues on your hard drive, or you will see the message 'No issues found'. You can also run the test multiple times by choosing the option 'Run test again'. To resolve the issue, press 'Get started' and resolve all the issues and try using Mac migration assistant again.

5 Try to migrate from a time machine backup.

If you have properly used all the above methods, you can try this last method of using the time machine, if you have one on your iMac. Try time machine to transfer your valuable data.

Extra Tips on Apple Migration Assistant

How can you transfer migration assistant to another Mac?

Step 1 Open Migration Assistant on your new Mac computer.

Step 2 Select transfer information 'from a Mac, Time Machine backup or startup disk'.

Step 3 Open Migration Assistant on your old Mac computer.

Step 4 Select to transfer to another Mac.

Step 5 Input security code in both new and old Mac PC.

Step 6 Select the information that needs to be transferred.

Conclusion

The issue of Mac migration assistant stuck or frozen may surely seem tricky to you. As there are multiple scenarios to this problem. The best thing you can do is to follow the given guidelines. If still, you are unable to solve the issue, the remarkable Time machine is at the service to solve this issue.

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In cryptography, a message authentication code (MAC), sometimes known as a tag, is a short piece of information used to authenticate a message—in other words, to confirm that the message came from the stated sender (its authenticity) and has not been changed. The MAC value protects a message's data integrity, as well as its authenticity, by allowing verifiers (who also possess the secret key) to detect any changes to the message content.

Terminology[edit]

The term message integrity code (MIC) is frequently substituted for the term MAC, especially in communications^[1] to distinguish it from the use of the latter as media access control address (MAC address). However, some authors^[2] use MIC to refer to a message digest, which aims only to uniquely but opaquely identify a single message. RFC 4949 recommends avoiding the term message integrity code (MIC), and instead using checksum, error detection code, hash, keyed hash, message authentication code, or protected checksum.

Definitions[edit]

Informally, a message authentication code system consists of three algorithms:

• A key generation algorithm selects a key from the key space uniformly at random.
• A signing algorithm efficiently returns a tag given the key and the message.
• A verifying algorithm efficiently verifies the authenticity of the message given the key and the tag. That is, return accepted when the message and tag are not tampered with or forged, and otherwise return rejected.

A secure message authentication code must resist attempts by an adversary to forge tags, for arbitrary, select, or all messages, including under conditions of known- or chosen-plaintext. It should be computationally infeasible to compute a valid tag of the given message without knowledge of the key, even if for the worst case, we assume the adversary knows the tag of any message but the one in question.^[3]

Formally, a message authentication code (MAC) system is a triple of efficient^[4] algorithms (G, S, V) satisfying:

• G (key-generator) gives the key k on input 1ⁿ, where n is the security parameter.
• S (signing) outputs a tag t on the key k and the input string x.
• V (verifying) outputs accepted or rejected on inputs: the key k, the string x and the tag t.

S and V must satisfy the following:

Pr [ k ← G(1ⁿ), V( k, x, S(k, x) ) = accepted ] = 1.^[5]

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A MAC is unforgeable if for every efficient adversary A

Pr [ k ← G(1ⁿ), (x, t) ← A^{S(k, · )}(1ⁿ), x ∉ Query(A^{S(k, · )}, 1ⁿ), V(k, x, t) = accepted] < negl(n),

where A^{S(k, · )} denotes that A has access to the oracle S(k, · ), and Query(A^{S(k, · )}, 1ⁿ) denotes the set of the queries on S made by A, which knows n. Clearly we require that any adversary cannot directly query the string x on S, since otherwise a valid tag can be easily obtained by that adversary.^[6]

Security[edit]

While MAC functions are similar to cryptographic hash functions, they possess different security requirements. To be considered secure, a MAC function must resist existential forgery under chosen-plaintext attacks. This means that even if an attacker has access to an oracle which possesses the secret key and generates MACs for messages of the attacker's choosing, the attacker cannot guess the MAC for other messages (which were not used to query the oracle) without performing infeasible amounts of computation.

MACs differ from digital signatures as MAC values are both generated and verified using the same secret key. This implies that the sender and receiver of a message must agree on the same key before initiating communications, as is the case with symmetric encryption. For the same reason, MACs do not provide the property of non-repudiation offered by signatures specifically in the case of a network-wide shared secret key: any user who can verify a MAC is also capable of generating MACs for other messages. In contrast, a digital signature is generated using the private key of a key pair, which is public-key cryptography.^[4] Since this private key is only accessible to its holder, a digital signature proves that a document was signed by none other than that holder. Thus, digital signatures do offer non-repudiation. However, non-repudiation can be provided by systems that securely bind key usage information to the MAC key; the same key is in the possession of two people, but one has a copy of the key that can be used for MAC generation while the other has a copy of the key in a hardware security module that only permits MAC verification. This is commonly done in the finance industry.^{[citation needed]}

Implementation[edit]

MAC algorithms can be constructed from other cryptographic primitives, like cryptographic hash functions (as in the case of HMAC) or from block cipher algorithms (OMAC, CCM, GCM, and PMAC). However many of the fastest MAC algorithms like UMAC-VMAC and Poly1305-AES are constructed based on universal hashing.^[7]

Intrinsically keyed hash algorithms such as SipHash are also by definition MACs; they can be even faster than universal-hashing based MACs.^[8]

Additionally, the MAC algorithm can deliberately combine two or more cryptographic primitives, so as to maintain protection even if one of them is later found to be vulnerable. For instance, in Transport Layer Security (TLS), the input data is split in halves that are each processed with a different hashing primitive (SHA-1 and SHA-2) then XORed together to output the MAC.

One-time MAC[edit]

Universal hashing and in particular pairwise independent hash functions provide a secure message authentication code as long as the key is used at most once. This can be seen as the one-time pad for authentication.^[9]

The simplest such pairwise independent hash function is defined by the random key, key = (a, b), and the MAC tag for a message m is computed as tag = (am + b) mod p, where p is prime.

More generally, k-independent hashing functions provide a secure message authentication code as long as the key is used less than k times for k-ways independent hashing functions.

Message authentication codes and data origin authentication have been also discussed in the framework of quantum cryptography. By contrast to other cryptographic tasks, such as key distribution, for a rather broad class of quantum MACs it has been shown that quantum resources do not offer any advantage over unconditionally secure one-time classical MACs.^[10]

Standards[edit]

Various standards exist that define MAC algorithms. These include:

• FIPS PUB 113 Computer Data Authentication,^[11] withdrawn in 2002,^[12] defines an algorithm based on DES.
• FIPS PUB 198-1 The Keyed-Hash Message Authentication Code (HMAC)^[13]
• ISO/IEC 9797-1Mechanisms using a block cipher^[14]
• ISO/IEC 9797-2 Mechanisms using a dedicated hash-function^[15]
• ISO/IEC 9797-3 Mechanisms using a universal hash-function^[16]
• ISO/IEC 29192-6 Lightweight cryptography - Message authentication codes^[17]

ISO/IEC 9797-1 and -2 define generic models and algorithms that can be used with any block cipher or hash function, and a variety of different parameters. These models and parameters allow more specific algorithms to be defined by nominating the parameters. For example, the FIPS PUB 113 algorithm is functionally equivalent to ISO/IEC 9797-1 MAC algorithm 1 with padding method 1 and a block cipher algorithm of DES.

An example of MAC use[edit]

^[18] In this example, the sender of a message runs it through a MAC algorithm to produce a MAC data tag. The message and the MAC tag are then sent to the receiver. The receiver in turn runs the message portion of the transmission through the same MAC algorithm using the same key, producing a second MAC data tag. The receiver then compares the first MAC tag received in the transmission to the second generated MAC tag. If they are identical, the receiver can safely assume that the message was not altered or tampered with during transmission (data integrity).

However, to allow the receiver to be able to detect replay attacks, the message itself must contain data that assures that this same message can only be sent once (e.g. time stamp, sequence number or use of a one-time MAC). Otherwise an attacker could – without even understanding its content – record this message and play it back at a later time, producing the same result as the original sender.

See also[edit]

• Hash-based message authentication code (HMAC)

Notes[edit]

1. ^IEEE 802.11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications(PDF). (2007 revision). IEEE-SA. 12 June 2007. doi:10.1109/IEEESTD.2007.373646. ISBN978-0-7381-5656-9.
2. ^Fred B Schneider, Hashes and Message Digests, Cornell University
3. ^The strongest adversary is assumed to have access to the signing algorithm without knowing the key. However, her final forged message must be different from any message she chose to query the signing algorithm before. See Pass's discussions before def 134.2.
4. ^ ^abTheoretically, an efficient algorithm runs within probabilistic polynomial time.
5. ^Pass, def 134.1
6. ^Pass, def 134.2
7. ^'VMAC: Message Authentication Code using Universal Hashing'. CFRG Working Group. Retrieved 16 March 2010.
8. ^Jean-Philippe Aumasson & Daniel J. Bernstein (2012-09-18). 'SipHash: a fast short-input PRF'(PDF).
9. ^Simmons, Gustavus (1985). 'Authentication theory/coding theory'. Advances in Cryptology: Proceedings of CRYPTO 84. Berlin: Springer. pp. 411–431.
10. ^Nikolopoulos, Georgios M.; Fischlin, Marc (2020). 'Information-Theoretically Secure Data Origin Authentication with Quantum and Classical Resources'. Cryptography. 4 (4): 31. arXiv:2011.06849. doi:10.3390/cryptography4040031. S2CID226956062.
11. ^'FIPS PUB 113 Computer Data Authentication'. Archived from the original on 2011-09-27. Retrieved 2010-10-10.
12. ^'Federal Information Processing Standards Publications, Withdrawn FIPS Listed by Number'. Archived from the original on 2010-08-01. Retrieved 2010-10-10.
13. ^The Keyed-Hash Message Authentication Code (HMAC)
14. ^ISO/IEC 9797-1 Information technology — Security techniques — Message Authentication Codes (MACs) — Part 1: Mechanisms using a block cipher
15. ^ISO/IEC 9797-2 Information technology — Security techniques — Message Authentication Codes (MACs) — Part 2: Mechanisms using a dedicated hash-function
16. ^ISO/IEC 9797-3 Information technology — Security techniques — Message Authentication Codes (MACs) — Part 3: Mechanisms using a universal hash-function
17. ^ISO/IEC 29192-6 Information technology — Lightweight cryptography — Part 6: Message authentication codes (MACs)
18. ^'Mac Security Overview', Mac® Security Bible, Wiley Publishing, Inc., 2011-11-01, pp. 1–26, doi:10.1002/9781118257739.ch1, ISBN9781118257739

References[edit]

• Goldreich, Oded (2001), Foundations of cryptography I: Basic Tools, Cambridge: Cambridge University Press, ISBN978-0-511-54689-1
• Goldreich, Oded (2004), Foundations of cryptography II: Basic Applications (1. publ. ed.), Cambridge [u.a.]: Cambridge Univ. Press, ISBN978-0-521-83084-3
• Pass, Rafael, A Course in Cryptography(PDF), retrieved 31 December 2015^[1]

External links[edit]

1. ^11-12-20C8