Graphic Commentary: What is digital signature

graphic Commentary: What is digital signatureIntroduction to digital signatures by David Youd
Preface

Recently in the Internet Browsing SSL protocol encryption related articles, the more sense of "digital signature" produced a little confusion. Search directly for "What is digital signature" and discover this early article:

Http://www.youdzone.com/signature.html, very early, but still intriguing. On the net paste also found the relevant translation: Http://www.ruanyifeng.com/blog/2011/08/what_is_a_digital_signature.html. Read down, think it this translation is actually just translation, even "story plot" are changed a lot, so they move hands, so there is this article.

translationBob has two keys, one is called the public key, the public key, and the other is called the private key.

Bob's public key is available to anyone who needs it, but his private key is reserved for himself. A key (public and private) is used to encrypt information. The process of encrypting information means "confusion" so that only the person with the appropriate key can make it readable again. Bob's two keys, any one used to encrypt data, the other to decrypt the data.

Susan (shown below) using Bob's public key to encrypt a message to Bob,bob, the private key is used to decrypt the information for reading. Any of Bob's colleagues may be able to get the information that Susan has encrypted, but without Bob's private key, the data is useless.

Using his private key and the appropriate software, Bob placed a digital signature in the document and some data. This digital signature, which Bob puts in the data, is the only "logo" for Bob, which is very hard to fabricate. Also, this signature ensures that any changes to the data will be detected.
When a document is signed, Bob's software compresses the data into just a few lines, a process known as a "hash check," and a few lines are called summaries of the information. (It is not possible to restore the information digest directly to the original data information)

Bob's software then uses his private key to encrypt the digest of the information, and the result is a digital signature.

Finally, Bob's software puts this digital signature in a piece with the information document. All the data has been identified.


Now Bob passes the document to Pat.

Plot tangled ing. (Tragedy, no story ...) ）

As it happens, Suan works at the company's CA Center (certificate authentication), and Susan can sign Bob's public key and some of his information, simply to make a digital certificate for Bob.

Now Bob's colleagues are able to make sure that the public key they have is bob by detecting Bob's trusted credentials. In fact, no one in Bob's company would accept the signature without Susan generating the certificate. This gives Susan the right to revoke the digital certificate that the private key has been compromised, which is almost impossible. Susan's CA certificate validation is widely accepted.
We went on to say that Bob sent the signed document to Pat. To verify the digital signature on the document, Pat first detects the certificate on the Bob document by using the public key of Susan (the CA) with the software. If the certificate is successfully untied, it proves that Susan generated it. After the certificate is untied, Pat can check to see if the document has been modified by contacting the CA center and comparing it with the information on the Bob Certificate.
Pat then gets Bob's public key from the certificate and uses it to detect Bob's signature. If Bob's public key is able to unlock the signature, Pat can determine that the signature was generated using Bob's private key, and that it matched the public key of the certificate that Susan issued. And if the signature is a cross-reference, it also explains that Doug could not modify the contents of the document.
Although these steps look daunting, they are hand-in-hand with Pat's user-friendly software scene. To verify the signature information, Pat simply clicks:

(Figure to verify the identity of the digital certificate)

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Graphic Commentary: What is digital signature