If this were not the case, then Alice and Bob can conclude Eve has introduced local realism to the system, violating Bell's Theorem.
RSA Data Security http: A personal certificate is a unique digital ID that can be used to identify you to a Web server and to other users. Personal certificates not widely used on the Web. Their major use is within corporate intranets, where the possession of a certificate is used to control access to confidential information on the corporate Web server.
However, many people think that personal certificates will be used in the not-so-distant future as legally binding electronic signatures in Internet-based financial and legal transactions. How secure are personal certificates?
Personal certificates use public key cryptography to sign and authenticate signatures. When you apply for a digital certificate, a private key is automatically generated for you and saved to the hard disk of your computer. During this generation process, you are prompted for a password, which will be used to encrypt the private key before saving it to disk.
This precaution lowers the risk that the key will be intercepted if the computer is compromised either physically or over the network. Unfortunately this scheme is not foolproof because the private key is only as secure as the software that manipulates it.
As described in the sections below, there are numerous known and potential security holes in browser software. If one of these holes is exploited to install new software on your computer or to modify the browser itself, then it is possible for the software to recover the private key from memory after it has been decrypted.
Once your private key has been intercepted, it can be used to impersonate you: In addition to the weaknesses of the software infrastructure, some security consultants have voiced particular concern about the security of the cipher system that Microsoft Internet Explorer uses to encrypt the private key.
The issues are obscure, controversial, and differ from version to version of IE. Under some circumstances Internet Explorer can be persuaded to export the private keys using weak bit encryption, a level of encryption that is known to be vulnerable to brute-force key guessing attacks. In other cases, the private key is vulnerable to fast "dictionary" attacks.
Full details can be found in an article written by Peter Gutmann pgut cs. In some countries, such as the United States, it is legal to use strong cryptography but software that implements it cannot be exported. In other countries, such as France, it is illegal to use strong cryptography at all.
The laws are changing rapidly. As I was writing this update in Decemberthe 33 countries in the Wassenaar Arrangement had agreed to establish the same cryptography export controls as the United States.
Recently the United States loosened the export restrictions slightly, allowing Web browsers to be used for strong encryption when communicating with financial institutions or when an American-owned company overseas needs to browse its home office's Web site.
Server certificates that allow for these specific exemptions can be obtained from VeriSign through its "step-up" program. More information on the legalities and politics of cryptography can be found at The Free Crypto Website. When I try to view a secure page, the browser complains that the site certificate doesn't match the server and asks me if I wish to continue.
The host name of the Web server is an unalterable part of the site certificate. If the name of the host doesn't match the name on the certificate, the browser will notice this fact and alert you of the problem. Sometimes this is merely an innocent server misconfiguration, but it can also be evidence that a server certificate has been stolen and is being used to fool you.
In most cases, it's best to abort the transmission. You may occasionally see a similar message that warns you that the server's certificate has expired. This may mean that the Webmaster hasn't renewed the site's certificate in a timely fashion, or may again indicate that the certificate has been stolen and is being misused.
Again, the safest course is to abort the transmission. When I try to view a secure page, the browser complains that it doesn't recognize the authority that signed its certificate and asks me if I want to continue.
Web browsers come with a preinstalled list of certifying authorities that they trust to vouchsafe the identity of Web sites.
A few years ago there was only one certifying authority, the VeriSign corporation, but now there are dozens. You can view the certifying authorities that your browser trusts by: In Netscape Navigator 1. The browser will display a scrolling list of CA certificates -- the master certificates that certifying authorities use to sign the certificates of individual Web sites.
Both the Netscape and Microsoft browsers allow you to view the contents of certificates, activate and deactivate them, install new certificates, and delete old ones. When a Web site presents your browser with a certificate signed by some authority, the browser will look up the authority's signature in its predefined list.
If the browser finds the signature, it will allow the SSL connection to continue.Where possible, use cryptographic techniques to authenticate information and keep the information private (but don’t assume that simple encryption automatically authenticates as well).
Generally you’ll need to use a suite of available tools to secure your application. Figure 1: Financial Cryptography in 7 Layers An advantage of this model is traversal from the technical to the application, giving major stakeholders easy points of entry.
We can start at the top, the Finance layer, and work top-down; this is a process of mapping requirements and . A Journey from JNDI/LDAP Manipulation to Remote Code Execution Dream Land. JNDI (Java Naming and Directory Interface) is a Java API that allows clients . Introduction.
Data that travels across a network can easily be accessed by someone who is not the intended recipient. When the data includes private information, such as passwords and credit card numbers, steps must be taken to make the data unintelligible to unauthorized parties.
Diffie–Hellman key exchange (DH) is a method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as originally conceptualized by Ralph Merkle and named after Whitfield Diffie and Martin Hellman.
DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography. Matt Curtin. March Reprinted with the permission of Kent Information Services, Inc. (Also available in Postscript and PDF formats for those who prefer, and nicer hardcopy.) Abstract: Network security is a complicated subject, historically only tackled by well-trained and experienced experts.