what is digital signature?

Answer 1

A digital code that can be attached to an electronically transmitted message that uniquely identifies the sender. Like a written signature, the purpose of a digital signature is to guarantee that the individual sending the message really is who he or she claims to be. Digital signatures are especially important for electronic commerce and are a key component of most authentication schemes. To be effective, digital signatures must be unforgeable. There are a number of different encryption techniques to guarantee this level of security.

Answer 2

Digital signature
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This article concerns cryptographic signatures. For signatures in digital form, see electronic signature.

In cryptography, a digital signature or digital signature scheme is a type of asymmetric cryptography used to simulate the security properties of a signature in digital, rather than written, form. Digital signature schemes normally give two algorithms, one for signing which involves the user's secret or private key, and one for verifying signatures which involves the user's public key. The output of the signature process is called the "digital signature."

Digital signatures, like written signatures, are used to provide authentication of the associated input, usually called a "message." Messages may be anything, from electronic mail to a contract, or even a message sent in a more complicated cryptographic protocol. Digital signatures are used to create public key infrastructure (PKI) schemes in which a user's public key (whether for public-key encryption, digital signatures, or any other purpose) is tied to a user by a digital identity certificate issued by a certificate authority. PKI schemes attempt to unbreakably bind user information (name, address, phone number, etc.) to a public key, so that public keys can be used as a form of identification.

Digital signatures are often used to implement electronic signatures, a broader term that refers to any electronic data that carries the intent of a signature[1], but not all electronic signatures use digital signatures.[2][3][4][5] In some countries, including the United States, and in the European Union, electronic signatures have legal significance. However, laws concerning electronic signatures do not always make clear their applicability towards cryptographic digital signatures, leaving their legal importance somewhat unspecified.

Definition

Main article: Public-key cryptography

A digital signature scheme typically consists of three algorithms:

* A key generation algorithm G that randomly produces a "key pair" (PK, SK) for the signer. PK is the verifying key, which is to be public, and SK is the signing key, to be kept private.
* A signing algorithm S, that on input of a message m and a signing key SK, produces a signature σ.
* A signature verifying algorithm V, that on input a message m, a verifying key PK, and a signature σ, either accepts or rejects.

Two main properties are required. First, signatures computed honestly should always verify. That is, V should accept (m, PK, S (m, SK)) whenever SK is the secret key related to PK, for any message m. Secondly, it should be hard for any adversary, knowing only PK, to create valid signatures

Answer 3

In cryptography, a digital signature or digital signature scheme is a type of asymmetric cryptography used to simulate the security properties of a signature in digital, rather than written, form. Digital signature schemes normally give two algorithms, one for signing which involves the user's secret or private key, and one for verifying signatures which involves the user's public key. The output of the signature process is called the "digital signature."

Digital signatures, like written signatures, are used to provide authentication of the associated input, usually called a "message." Messages may be anything, from electronic mail to a contract, or even a message sent in a more complicated cryptographic protocol. Digital signatures are used to create public key infrastructure (PKI) schemes in which a user's public key (whether for public-key encryption, digital signatures, or any other purpose) is tied to a user by a digital identity certificate issued by a certificate authority. PKI schemes attempt to unbreakably bind user information (name, address, phone number, etc.) to a public key, so that public keys can be used as a form of identification.

Digital signatures are often used to implement electronic signatures, a broader term that refers to any electronic data that carries the intent of a signature, but not all electronic signatures use digital signatures. In some countries, including the United States, and in the European Union, electronic signatures have legal significance. However, laws concerning electronic signatures do not always make clear their applicability towards cryptographic digital signatures, leaving their legal importance somewhat unspecified.

A digital signature scheme typically consists of three algorithms:

* A key generation algorithm G that randomly produces a "key pair" (PK, SK) for the signer. PK is the verifying key, which is to be public, and SK is the signing key, to be kept private.
* A signing algorithm S, that on input of a message m and a signing key SK, produces a signature σ.
* A signature verifying algorithm V, that on input a message m, a verifying key PK, and a signature σ, either accepts or rejects.

Two main properties are required. First, signatures computed honestly should always verify. That is, V should accept (m, PK, S (m, SK)) whenever SK is the secret key related to PK, for any message m. Secondly, it should be hard for any adversary, knowing only PK, to create valid signatures

Answer 4

Digital Signatures often used to implement electronic signatures, a broader term that refers to any electronic data that carries the intent of a signature, but not all electronic signatures use digital signatures. In some countries, including the United States, India, and members of the European Union electronic signatures have legal significance.

Answer 5

in simple words .. digital signature is a signature encrypted digitally...

use/need : in any electronic communication for authentication of sender.

it can be a simple name of the person or any quote u wana send as ur signature. this text will be encrypted (hidden using complicated algorithms) & attached to the electronic msg which u send...