Questions tagged [signature]

Algorithms and protocols for creating signatures to documents, and verifying such signatures. These are normally asymmetric, for symmetric signatures see [mac].

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What do people use non-extractable WebCrypto keys for?

I understand that non-extractable keys are secure because they cannot be exported. But I think many people would WANT to export their keys at some point if they don't want to risk losing everything. ...
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Elliptic curve digital signature formats

There is app built on Java library github/esig/dss and goal is to add remote signatures to PDF files. Different methods create different formats of signatures. How to convert between them? Especially ...
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ECDSA: with knowledge of private key, can we make signatures with partially chosen content?

In ECDSA, with knowledge of private key, can we make signatures with partially chosen content? Detailing that: In ECDSA (with secp256r1 curve and SHA-256 hash), assume we know the private key, the ...
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How can I prove ownership of hardware wallet?

I’m applying for a mortgage loan and I recently made a large deposit into my bank account from crypto stored on a ledger hardware wallet . I sent the funds to Coinbase where I converted to usd and ...
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step by step example of EC signature

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Using the JarSigner with RSASSA-PSS [migrated]

Im trying to RSA-PSS-sign a JAR file with the JarSigner using PKCS#11. To specify the signature algorithm the JarSigner uses the sigalg flag. The JDK 14 Docs of the JarSigner does not specify which ...
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Chaining signatures of different parties

My question might be quite beginner, so please pardon my ignorance :) So, assume there are 10 parties, each with their own keypairs. There is a message $M$ that is passed from one party to the next. ...
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Public key decryption?

In the article How Does the Blockchain Work? the writer makes the following statements: Since only you should be able to spend your bitcoins, each wallet is protected by a special cryptographic ...
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Integrated Signatures and Encryption Scheme

Suppose we have a scheme ISE that combines $n$ signature schemes and one encryption scheme, where the same keys are used. It is composed of the following algorithms: Setup, KeyGen, $Sign_1,...,Sign_n, ...
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Message mapping to elliptic curve in BLS signature

In the BLS signature the subgroup $G$ of elliptic curve constructed with point $P$ with prime order $q$ by $G=\langle P\rangle $. The $h(x)$ is a hash function. The point $S$ is map (image) of $h(m)$ ...
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Is BBS+ 1. a multi-messages signing protocol or 2. a group signature signed by a member of a group anonymously?

There's no doubt that the BBS Signature was born from this classic Short Group Signature paper in 2004. It's capable of Zero-knowledge. In the paper, section 5, it describes how a member of a group, ...
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Mapping the hash of message to a point of elliptic curve for signature

Let the subgroup $G$ of elliptic curve constructed with point $P$ with prime order $q$ by $G=\langle P\rangle $. The $h(x)$ is a hash function. We want to map the hash of arbitrary message $m$ to a ...
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Is it possible to derive a constant value from different signatures of a private key?

For example perhaps deriving the same PRF from RSA signatures on different messages from a (not known) private key? Struggling to find the proof of why not.
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How do I calculate Base64 conversion rate?

Basically I need to have a base64 encoded signature that has to be 96 characters long. However, I do not know what length I need to have the signature at so when I encode it, it can be that exact size....
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In q-SDH problem, where are those points $\frac{1}{\beta+x}g$ or $g_1^\frac{1}{x+c}$ on elliptic curve?

For the q-SDH problem, given the generator $g_1$ as a point on the elliptic curve, I can picture the $\beta g_1, \beta^2g_1, ..., \beta^qg_1$ since we can simply do the point adding $g_1$ multiple of $...
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Is that proved that breaking ECDSA as hard as solving ECDLP? [duplicate]

Is that proved that breaking ECDSA (Elliptic Curve Digital Signature Algorithm) as hard as solving ECDLP(Elliptic Curve Discrete Logarithm Problem)?
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Can one extract a private key from a series of carefully constructed signed messages?

In a situation in which A handles a message P for B to sign using ECDSA, and that event repeats itself many times, is there a way A can discover B's private key? A ...
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Why blind signature schemes provides an easy way to “vote market” in electronic voting?

Recently I learned about Blind Signatures and why people say they are not really usefull for electronic voting. They ensure that you can easily "sell" your vote and this is something ...
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What is the advantage of Encrypt-then-MAC over Encrypt & MAC separately the plaintext [duplicate]

For secrecy, authentication & integrity, you can either use CipherText = Encrypt(PlainText) Signature = Hash(PlainText) CipherText = Encrypt(PlainText) Signature = Hash(CipherText) Either ...
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Can I use the same key pair for authentication and Diffie-Hellman? [duplicate]

Assume Alice has a key pair $(A, a)$ and Bob has a key pair $(B, b)$, where $A = Ga$ and $B = Gb$. In general, the basic rule of crypto says that we should not use the same key for different ...
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May an adversary be fooled by a random-looking input that in reality is fixed?

I want to prove the EUF-CMA-security of a signature scheme. It is a variation on an established scheme, therefore I would ideally like to reduce the new-scheme-security to the old-scheme-security. the ...
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How to simplify a the signing process in an elliptic curve signature scheme that involves a quadratic verification equation?

I am looking at a proprietary signature scheme used in production. It involves a short Weierstrass curve $E_{\mathcal{W}}:y^2=x^3+ax+b$ in the prime field $\mathbb{F}_p$. The parameters are set up ...
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Are group signatures already in practice?

Even group signautres have been discussed using in practice I could not see any real life application. Ring signatures are already in use for e-voting. I want to know whether group signatures are ...
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Avoid storing the whole message when signing with SPHINCS+

Unlike pretty much every other signature scheme that I am aware of (excluding Picnic, the original SPHINCS, and SPHINCS-gravity) SPHINCS+ requires that the whole message be available during the ...
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Do hash functions for digital signatures need to be preimage resistant?

I understand that hash functions used for hashing a document or some data before signing it, needs to be collision resistant and 2nd pre-image resistance. Otherwise an adversary could "look" ...
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Bitcoin ECDSA signature

I am trying to use the ecdsaSign function in ecdsa.c of https://github.com/kvhnuke/Ethereum-Arduino/tree/master/Ethereum-Arduino/libs which is based on the files in the repo https://github.com/...
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RSASSA-PSS in TLS 1.2

I know it is possible to use RSASSA-PKCS1-v1_5 with client certificates in TLS 1.3. But what about the other way around: using RSASSA-PSS with client certificates in TLS 1.2? Is it possible to use ...
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How many JWT tokens may be securely generated with one secret?

I can remember from my crypto classes, that there is a limit on how many blocks can be securely encrypted with the same key. Before we reach the limit, we should rotate the key. Does it also hold true ...
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Creating hash data signatures using RSA-CRT

I have taken two prime numbers p=137 q=131 M=64 and i want to create a digital signature ...
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How SPHINCS+ Hash Signature ADRS structure define

can anyone help me to elaborate the structure of ADRS with example ( tree ADRS, layer ADRS, keypair ADRS etc)used to generate root SPHINCS+ signature. Also can some one help me to describe tree hash ...
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Difference Between an Authentication Token and an OTP (One Time Password)

I would like to better understand why some people use the term One Time Password and other Authentication Token. I have noticed that in academic circles, there is a differentiation between ...
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Digital Signature or MAC Yielding Non-Binary Verification Predicate

Is there a digital signature or MAC scheme in which, the verification algorithm returns not $\{\text{Valid},\text{Invalid}\}$, but a discrete (finite or infinite) set of result such as $\{\text{Valid-...
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Is there any proof for ECDSA signature algorithm?

Related: Is there an interactive version of ECDSA signature protocol like the Schnorr identification protocol?
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Digital Signature Complexity [duplicate]

I'm not familiar with algorithm complexity so I'm asking here. I need help determining degital signature complexity, I did some research and all I found is complexity for the D.S.A only: 𝑂(𝐷𝑆𝐴 𝑆𝑖...
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What's the least computationally expensive way to verify a message is from who they say they are?

We're building an ingame GPS system where only 5 lines of code are executed a second. We're starting to face problems with people spoofing the satellites we use to triangulate. Is it feasible to ...
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How exactly is signature verification done in SSH v2 authentication?

One of the authentication methods in SSH involves the client signing a message with its private key and sending it to the server for verification. RFC 4252 (page 9) says: ...
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Signing a GPG Public Key

I am trying to manually create a GPG Public Key (see here). I am able to generate a GPG Public Key with a correct hash, but fail to RSA-sign that hash in a way that is accepted by the GPG CLI. For the ...
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Chaining one-time signatures

To introduce the notation for the question, consider a one-time signature algorithm: There are a private signing key $sk$ and a corresponding public key $pk$, generated by $Gen(seed)$. To sign a ...
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An aggregate signature scheme for transactions

Suppose A and B communicates where A makes B some payments by sending signatures as the following, $$ \sigma_1 \leftarrow Sign(v_1, sk_A), \sigma_2 \leftarrow Sign(v_2, sk_A), \dots \sigma_n\...
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Can the EdDSA signature scheme be customized with OpenSSL?

EdDSA has currently 2 signature scheme Ed25519 and Ed448 where Ed25519 is the EdDSA signature scheme using SHA-512 (SHA-2) and Curve25519 Ed448 is the EdDSA signature scheme using SHAKE256 (SHA-3) ...
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Proof by reduction for for digital signature scheme $S_2((sk_0,sk_1), m):=(S(sk_0,m), S(sk_1,m))$

Let $(Gen,S,V)$ be a secure signature scheme (existentially unforgeable under a chosen message attack) with message space${\{0,1\}}^n$. Generate two signing/verification key ...
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Same private key for signing and decryption

I am designing a service which identifies records with public keys. All other fields are encrypted with that public key and protected by a HMAC. For authentication, I am thinking about signing ...
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Manually creating a GPG Public Key

I want to manually create a GPG public key that can be imported into GPG, i.e. I want to create a file with a Public-Key Packet, a User ID Packet and a Signature Packet (for an example see here). I ...
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Likelihood of signature collision with EdDSA

Taking EdDSA as an example, given the length of a signature is 512-bits for a given data payload, what is the probability of a collision where there is another 512-bit value that is also a valid ...
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Performing EdDSA/Ed448 employing Montgomery ladder

EdDSA can be efficiently performed employing the Montgomery ladder. In order to implement this method, the base point should be converted to Mont. space, then the Mont. ladder should be executed, and ...
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Is it fair to say that MACs use a signing algorithm?

The Wikipedia page on MAC calls the algorithm that is used to generate the MAC as a signing algorithm. Is that a fair use of that term? Can we then say that HMAC-SHA-1 uses SHA-1 as the signing ...
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How does CL signature work?

I'm studying the CL signature that how can it works. However, I cannot understand how equation (42) is calculated. What is the last three factors? The value T is as follows: $$T \leftarrow(A')^{\...
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Functional signatures vs homomorphic signatures

I found that homomorphic signatures allows an agency to carry out arbitrary computation $f$ on the signed data $m$ and accordingly gain a signature for the computation result $f(m)$ with respect to $f$...
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Sensible amateur usage of web crypto API

I want to know if my usage of the web crypto API is sensible. I want to use it for symmetric and public-key encryption and decryption, and signatures, but as a non-expert I am scared by the warning on ...
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Can we defends against RSA Timing attack when we use java.math.BigInteger.modPow?

I think that Montgomery and sliding window techniques are applied within java.math.BigInteger.modPow (and more specifically ...

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