Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [blind-signature]

In a blind signature scheme, the signer does not know what he is signing. This is an important building block of anonymous voting or digital cash schemes, because it allows an authority to control the creating of signed messages, but doesn't allow it to track their use.

0
votes
0answers
70 views

ZKP for elements in blind signature

I want to be able to prove I know the elements $m$, $r$ of a blind signature (say RSA) and that I know $r$ is a secret key corresponds to one of a group of public keys. Specifically - Say I have $C =...
0
votes
0answers
16 views

Why would multiple messages need to be signed in an anonymous credential system?

I'm reading through Signature Schemes and Anonymous Credentials from Bilinear Maps, and the signature scheme that they build up to involves a signature on a tuple of messages $(m_1,m_2,...,m_n)$. Can ...
3
votes
1answer
111 views

Double spending on a given Blind Signature over ECC protocol

Here's a blind signature protocol based on ECC. The question is if it has the double spending problem? As I investigated, if we can change the c without changing ...
10
votes
0answers
274 views

Potential Flaws With Lattice Based Cryptography?

From researching post-quantum cryptographic schemes it seems hash-based and lattice-based algorithms are the most promising (MQ-based seem to be covered by patents and have more potential unknowns ...
3
votes
1answer
70 views

Are Blind Signatures Fundamentally Different From Signatures of Hashed Values?

I've been reading up on blind signatures and am trying to wrap my head around the concept - specifically in the context of anonymous blockchain transactions using vouchers. One particular issue I'm ...
4
votes
2answers
266 views

Post-Quantum Blind Signatures?

Are there any post-quantum blind signature algorithms? Since hash-based blind signature schemes have proven to by impossible (based on a response to this question) is this an active area of research ...
2
votes
2answers
145 views

Blind Hash Signatures?

Is it possible to implement blind signatures with purely hash-based signature algorithms? Any whitepapers, code samples, etc on the subject would be helpful.
5
votes
1answer
136 views

Is there a standard padding/format for RSA Blind Signatures?

I'm working on a RSA blinded signature scheme. RSA Blind signatures are discussed in Chaum's original paper and other places like wikipedia. The descriptions of RSA blind signatures are straight ...
1
vote
0answers
73 views

Missing step in Schnorr's proof that an attack on blind signatures requires solving ROS?

In Security of Blind Discrete Log Signatures Against Interactive Attacks C.P. Schnorr defines the ROS Problem and claims that a $(l+1)$ attack against his blind signature scheme is equivalent to ...
4
votes
1answer
210 views

Are (EC) DSA blind signatures possible?

I've been searching for a way to create blind ECDSA signatures. My research and experimentation has led me to believe that this is not possible. I've been attempting to articulate why and I think ...
1
vote
1answer
72 views

Is this schema secure?

I want to know if we use function H as random oracle in RSA Blind Signature and assume that RSA Assumption is correct, is it true that the ...
7
votes
1answer
520 views

How secure is a blind signature?

From Wikipedia: Blind signatures can also be used to provide unlinkability, which prevents the signer from linking the blinded message it signs to a later un-blinded version that it may be ...
1
vote
0answers
72 views

Digital cash and blind signiture: coherence between signature and serial number

My question is about the basics of the topic "creating digital cash". At the very beginning of that topic the amount of the banknote and a serial number are the requirements for generating a ...
6
votes
1answer
85 views

Blind signatures security

I was reading up on blind signatures. I came across the following paragraph in this paper. Previous methods of proofs used to establish security arguments for signature schemes no longer work ...
1
vote
0answers
98 views

What are the best practice, and standard tools for blinding algorithms?

I'm developing an app that uses blind signatures. I'm having a hard time finding tools, and best practices for blinding. There is no PKCS. And everywhere I go, I find caveats of different blind ...
1
vote
0answers
102 views

Padding for blinded messages?

I have a message $m$ that I wish to send as a blinded message for approval (a signature) to then unbind and use as authority. Should I preform the procedure like so: pad $m$ using EMSA-PSS (...
3
votes
1answer
162 views

Anonymity problem after voting with blind signatures

In a distributed voting system (all the messages are public, but signed and maybe encrypted/blinded), having: $d$, $e$, $N$ — registrar key params $m$ — msg $r$ — random blinding factor $m'$ — ...
4
votes
0answers
256 views

Elliptic Curve Blind Signature Implementation

I have seen this prior post: Elliptic Curve based blind signature implementation Currently I'm sizing up how difficult it would be to attain Elliptic Curve Blind signatures for an application I'm ...
1
vote
0answers
130 views

Is the half-homomorphic property of RSA a problem for blind RSA signatures?

For blind RSA signatures, is it problematic that RSA is half-homomorph? Take a scenario where blind RSA signatures are used for something like a voting procedure or this proposal: Lots of people, ...
0
votes
0answers
635 views

Python implementation of a blind signature scheme which doesn't involve RSA

RSA seems a bit creepy after the Snowden revelations and i'm looking for a simple python based blind signature library to fiddle around with. So far i've been unable to find anything. What am i ...
2
votes
1answer
375 views

RSA-blind signatures vs. DSA-blind signatures

I see that the RSA blind signature scheme tends to be implemented more often than others, e.g., DSA blind signatures. Isn't the RSA blind signature scheme a 'lesser' scheme, if you may, compared to ...
2
votes
1answer
563 views

How does Schnorr signature actually work?

I'm trying to get a grip on how Schnorr signature works. Suppose Alice sends Trent a tuple $(P, M)$, which contains a payload and a message to be signed by him. She then passes the certificate to Bob ...
4
votes
1answer
2k views

RSA Blind Signature Attack

In Information Security Class I learned a non-adaptive chosen ciphertext attack using "blinding" but I just can't follow the proof and therefore can't reconstruct it. From what I've found out, it ...
2
votes
0answers
599 views

Elliptic Curve based blind signature implementation

I want to use Elliptic Curve based blind signature scheme for my research. There is no proper implementation of ECC-based blind signatures. Can someone describe to me which things I need to follow ...
3
votes
1answer
709 views

ECC partially blind signature scheme verification

Continued from Is there a flaw in this ECC blind signature scheme? The problem I needed a partially blind signature scheme for one of my projects, but couldn't find one on the internet, so I've made ...
5
votes
0answers
500 views

Is there a flaw in this ECC blind signature scheme?

Recently I've found the following work on the internet: An ECC-Based Blind Signature Scheme The paper claims to be an ECDSA blind signature however it seems that their scheme has a flaw in it. The ...
1
vote
1answer
100 views

Is there an anonymous non-interactive authorisation scheme with peer-side auth. signature generation?

I implemented a pseudonymous PKI scheme (by K. Zeng @Springer Link), where all peers can change their public keys including its signature on their own. I am looking for a way to extend it with some ...
1
vote
1answer
304 views

Sequence of Encrypting RSA like Chaum Blinding scheme

I'd be a noob in cryptography but reading up a little on RSA, I do get some understanding and I want to specifically resolve this issue. UPDATED Lets say we have the following values in place: <...
1
vote
0answers
195 views

Going Blind, Group or Ring?

I have several problems approaching the following problem: Let's assume that we have Alice, Bob and Cathy. Alice wants to present a message to Cathy, showing her that someone else has signed it (Bob), ...
3
votes
2answers
240 views

Usability of padding scheme in blinded RSA signature?

In Wikipedia's article on Blind signature, in the section Dangers of blind signing which describes RSA blinding attack one reads the following This attack works because in this blind signature ...
1
vote
1answer
430 views

Unblind a RSA blinded signature

I have blinded $m = 16$ with $r= 13$, $e = 7$ and $n = 209$. This resulted in $m' = 464$, which led to a $s' = 8$. Now, I want to unblind this $s'$ by using $s = s' \times r^{-1}$ but im stuck at ...
7
votes
1answer
391 views

Blinding twice in RSA

I understand that if you have a message $m$, you can blind it by selecting a random $r$ and then multiplying $r^e\times m \pmod{n}$ Someone else then signs it with $d$, raising to the power of $d$: $(...
0
votes
2answers
357 views

Blind Signatures

The verification algorithm given in blind signature. Should it work for both Original message and the signature on it Blinded message and the signature on it. If yes, then how can we verify if the ...
0
votes
1answer
277 views

blinding a hash vs. sending the hash directly

So with blind signatures you have two parties - A and B. A has a message that they want B to sign so A creates a hash of their message, blinds it, and then sends it to B to sign. That, as I understand ...
1
vote
1answer
508 views

PKCS1 and blind RSA signatures

Wikipedia's article on RSA blind signatures says that you need to raise the message $m$ to the secret exponent $d$ modulo the public modulus $N$. Implicit within that, it seems to me, is that m needs ...
8
votes
1answer
3k views

What is “Blinding” used for in cryptography?

What does "blinding" mean in cryptography, and where do we usually use it? Can you describe a sample implementation?
8
votes
2answers
3k views

RSA blind signatures in practice

Hi I have a problem with moving my blind signature implementation from educational (textbook RSA) to more practical (padded RSA) side. David Chaums paper gives a following figure: $r$ - blinding ...
5
votes
1answer
302 views

One-way hash on encrypted data, result hidden from hasher

I'm looking for a one-way hash function that can be performed by A on an encrypted piece of data E(D) provided by B, without the performer A able to figure out D or H(D). This similar to HMAC(Message, ...
15
votes
2answers
2k views

Which blind signature schemes exist, and how do they compare?

I'm looking into blind signature schemes for use as digital cash. I have come across blinded RSA, and Lucre(DH based). Are there other schemes available, and how do they compare? I suspect there ...
6
votes
1answer
748 views

Blind signature with openssl

I'm trying to understand (to reproduce in practice) how does blinded tokens work. Currently i'm lacking examples. According to Wiki the blinded signature protocol is the same as ordinary signature ...
4
votes
1answer
120 views

Is there any serious discussion about using blinding intermediaries in digital currency scenarios?

A digital currency system like Lucre (OpenTransaction) creates a coin by a mint blind signing the output of a hash function, which the payer then unblinds and pairs with the input to the has function. ...