Digital Signatures Explanation of Terms briefly describe the principles of digital signatures

Digital signatures. It is a normal physical signature similar to that written on paper, but used.

Public-key cryptography. The technical implementation of the field, the method used to identify digital information. A set of digital signatures typically defines two complementary operations, one for signature and one for verification.

A digital signature is a string of numbers that can only be generated by the sender of the message and cannot be forged by others, and this string of numbers is also sent to the sender of the message.

Authenticity of information.

A valid proof of this.

The integrity of a digitally signed file is easy to verify (not required.)

Ride the sewing chapter. Riding a seam signature, there is also no need for a handwriting expert), and the digital signature has.

Non-repudiation.

Undeniable.

Extended Information: Digital Signature Technology.

is to use the summary information with the sender.

Private. Encrypted, transmitted along with the original text.

Receiver. The receiver can only decrypt the encrypted digest message with the sender's public key, and then use it.

hash function.

Generate a summary message of the received source text and compare it with the declassified summary message.

If it is the same, it means that the information received is complete and has not been modified during transmission, otherwise the message has been modified, so the digital signature can verify the integrity of the information. Digital signature is an encryption process, and digital signature verification is a decryption process.

Encyclopedia. Digital signatures.

The Great Password Part 3: The Role of Digital Signatures.

Digital signature, also known as public key digital signature and electronic signature, is an ordinary physical signature similar to written on paper, but it is implemented using technology in the field of public key cryptography to identify digital information. A digital signature is some data attached to a data unit, or a cryptographic change made to a data unit.

The so-called digital signature is to generate a series of symbols and ** electronic password for signature through a certain cryptographic operation, to replace the written signature or seal, for this electronic signature can also be technically verified, and the accuracy of its verification is incomparable with the verification of general manual signatures and stamps.

A digital signature is not a digital image that scans your signature, or a signature that is captured with a touchpad, nor is it your signature. A digital signature (also known as a public key digital signature or electronic signature) is a method used to identify digital information similar to an ordinary physical signature trapped on paper, but using the technical implementation in the field of public key cryptography.

Digital certificates use a public key system (asymmetric key), that is, a pair of keys that match each other are used for encryption and decryption.

Digital signature trembling refers to the data obtained by the user encrypting the hash digest of the original data with his own private key.

RSA Algorithm DescriptionThe RSA algorithm is a relatively complete public-key cryptography system proposed by Rivest, Shamir, and Adleman in 1977. The RSA algorithm is a public-key algorithm that can be used for both encryption and digital signatures.

A digital signature is a piece of data attached to a unit of data, or a cryptographic transformation of a unit of data. This type of data or transformation allows the recipient of the data unit to confirm the integrity of the data unit and to protect the data from being forged by someone (e.g., the recipient).

It is a method of signing messages in electronic form, and a signed message can be transmitted over a communication network. Both public-key and private-key cryptography can obtain digital signatures, mainly digital signatures based on public-key cryptography. This includes both ordinary and special digital signatures.

a.Convenience.

b.It is not possible to create a pseudo-acacia.

c.Evidence of recognizable nuclear segments.

d.It is undeniable.

Correct answer: BCD

So-called"Digital signatures. "It is through a certain cryptographic operation to generate a series of symbols and ** to form an electronic password for signature, to replace the written signature or seal, for this electronic signature can also be technically verified, the accuracy of its verification is the verification of the general manual signature and seal and can not be compared. "Digital signatures. "At present, it is the most widely used, the most mature and the most operable electronic signature method in e-commerce and e-government. It uses standardized procedures and scientific methods for the identification of signatories and the recognition of the content of an electronic data.

It can also verify that the original text of the document has not been changed during transmission, ensuring the integrity, authenticity and non-repudiation of the transmitted electronic document.

Digital signatures are defined in the ISO7498-2 standard as:"Some data attached to a data unit, or a cryptographic transformation of a data unit, that allows the recipient of the data unit to confirm the integrity of the data unit** and the data unit, and to protect the data from being forged by someone (e.g. the recipient)."。The American Electronic Signature Standard (DSS, FIPS186-2) explains digital signatures as follows:

The result of the calculation of the data using a set of rules and a parameter can be used to confirm the identity of the signer and the integrity of the data"。As defined above, PKI (Public

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PKI) provides cryptographic transformations that provide units of data and enable the recipient to judge and validate the data**.

The core executive body of PKI is the electronic certification service provider, which is commonly known as the certification body CA (Certificate).

Authority), the core element of PKI signature is a digital certificate issued by a CA. The PKI services it provides are authentication, data integrity, data confidentiality and non-repudiation. It uses the public key of the certificate and the corresponding private key to encrypt and decrypt, and generates the signature of the digital message and the verification signature.

Digital signature is the use of public key cryptography and other cryptographic algorithms to generate a series of symbols and form an electronic password for signature, instead of writing signatures and seals; This electronic signature can also be technically verified, and its accuracy is unmatched in the physical world for the verification of manual signatures and stamps. This signature method can be authenticated in large groups of trusted PKI domains, or cross-authenticated across multiple trusted PKI domains, and is particularly suitable for secure authentication and transmission on the Internet and WAN.

Digital signature technology is an application of cryptography technology under the public key cryptography system, which mainly has two characteristics: on the one hand, digital signatures can only be managed and used by their legitimate holders, and because the private key cannot be stolen, it has high encryption. When using digital signatures, they need to be verified, and the physical identity of the signer needs to be fully verified in the process; On the other hand, when generating a digital signature, it is necessary to use the operation steps of the hash algorithm, so that the specific signature of the message and the number can be corresponded, so that when verifying it, it is necessary to verify the integrity of the data message, and once it is unreasonable problem, it can be found in time.

The use of digital signatures has a good effect of anti-repudiation and integrity protection, and has an important influence and role in the current network information technology.

The so-called "digital signature" simply means that a unique electronic password is generated through a certain cryptographic operation, and this unique electronic password is used instead of writing a signature or seal.

The core executor of digital signature technology is the electronic authentication service provider, which is commonly known as the CA Certificate Authority. The digital certificate issued by the CA agency records the identity information of the parties to the contract on the Internet, etc., and can be understood as the "electronic identity card" of the parties to the contract, which is used to ensure that the identity of the contract signatory is identifiable and cannot be repudiated.

In short, digital signature, as a technical means, is one of the commonly used ways to achieve electronic signatures in the world.

The concept of digital signature: data that exists in electronic form in a data message, or is attached to it or logically linked to it, can be used to identify the data signer and indicate the signatory's approval of the information contained in the data message.

How a digital signature works: "When sending a message, the sender uses a hash function to generate a digest from the packet text, and then encrypts the digest with its own private key, and the encrypted digest will be sent to the receiver as the digital signature of the packet, and the receiver first uses the same hash function as the sender to calculate the packet digest from the original packet received, and then uses the sender's public key to decrypt the digital signature attached to the packet. The receiver then confirms that the digital signature belongs to the sender. Digital signatures serve two purposes:

One is to be sure that the message was indeed signed and sent by the sender, because others cannot fake the sender's signature. Second, digital signatures can determine the integrity of messages. Because a digital signature is characterized by the fact that it represents the characteristics of a file, if the file changes, the value of the digital signature will also change.

Different files will get different digital signatures. A digital signature involves a hash function, the sender's public key, and the sender's private key. "The description of this message identification!

Digital signatures are not that complicated. Digital signature: The sender uses its own key to perform D operations on packet X, generates an unreadable ciphertext DSK, and then transmits DSX to the receiver, who uses the sender's key to perform E operations to restore the packet in order to verify the signature.

Each person has a pair of "keys" (digital identities), one of which she knows only (the key) and the other that is public (the public key). Use a key when signing, and a public key when verifying a signature. And because anyone can claim that she is you, the public key must be registered with someone trusted by the recipient (the identity authority).

After registration, the identity authority will issue you a digital certificate. After signing the document, you send the digital certificate to the recipient along with the document and signature, and the recipient asks the identity authority to verify that the document was actually issued with your key.

Public key passwords are not only digitally signed, but also secure and convenient, and easier to achieve the effect of written signatures than traditional passwords, so public key passwords are very popular!

Since there are various forms of digital signatures, such as universal digital signatures, arbitrated digital signatures, non-repudiation signatures, blind signatures, group signatures, threshold signatures, etc., here I will answer it with the general method of digital signatures!

1) Both A and B publicly register their public key KE and store it in the shared public key database PKDB in the management center, which is one of the data for the other party and the arbiter to verify the signature.

2) A signs the plaintext data M with its own confidential decryption key KDA to get the signature S, and then A queries PKDB to find B's public key kea, and re-encrypts the ciphertext C with kea to S

3) Finally, A sends C to B, and S and C are left behind.

3.The digital signature adopts the method of double encryption to achieve anti-counterfeiting and anti-reliance. Here's how it works:

1. The sent file is encrypted with SHA encoding to generate a 128-bit digital summary.

2. The sender uses its own private key to encrypt the digest, which forms a digital signature 3. The original text and the encrypted digest are transmitted to the other party at the same time.

4) The other party decrypts the digest with the sender's public key, and at the same time generates another digest with SHA encoding of the received file.

5) Compare the decrypted digest with the digest generated by the re-encryption of the received file at the receiver. If the two are consistent, it means that the information has not been destroyed or tampered with during transmission. Otherwise, it is not.

When B receives packet X, in order to verify whether the packet was sent by A or whether the packet has been intercepted or tampered with during transmission, A uses A's public key PK(A) to decrypt packet X and obtain a readable and correct packet, indicating that it was sent by A and has not been tampered with. Conversely, if an unreadable packet is decrypted, it is not sent by A or tampered with.

The function of the digital signature can be obtained from the above text: message authentication (the receiver can verify the sender's signature on the message), integrity of the message (the message has not been tampered with in the middle of the message), and non-repudiation (A's private key has encrypted the message, and A's private key is known only to A).