Questions tagged [jwt]

JWT specifies JSON web tokens. It is defined in RFC 7519: JSON Web Token (JWT)

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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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1answer
54 views

What is a “set synchronized CSPRNG”?

I'm looking to implement a performant revocation method for JWTs. I'm reading a paper, in which the following section's second paragraph states: If we use the client hashing approach described ...
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56 views

How RSA is implemented by authentication protocols?

I am a beginner in cryptography, i recently learned about RSA algorithm : In short, my understanding for this is : Sender needs receiver's public key to encrypt the message to a cipher so that only ...
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91 views

Validating JWT works with small changes to public key, why?

I was trying to verify the following JWT on JWT.io with the following public key: ...
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75 views

JWTs vs Capability Tokens

One of the primary advantages of JWTs is that they serve as capability tokens, allowing for a portable verification of capabilities/ privileges. However, JWTs are often criticized for a number of ...
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1answer
160 views

Are there any security drawbacks for simply encrypting and MACing my JWS token (JWT)?

This question, while related, doesn't answer the security aspect I have in mind. I understand that signatures make it impossible for the tokens to be modified. But if I want the JWS token content to ...
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1k views

JWT Login Security

I am new to security and I am wondering if JWT is secure enough. From what I have read online the flow goes like this: Clients log in by sending their credentials to the identity provider. The ...
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3answers
680 views

Base64 encoding of strings

I have read everywhere that base64 encoding of unique binary/hex values results in unique output. The following two string encode to virtually the same output. ...
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1answer
9k views

How can one validate with a public key a JWT signature generated with a private key?

As I understand it, a JSON Web Token (JWT) consists of 3 parts: the header, specifying the hashing algorithm to use for the signature; the payload itself; and the signature, which is a hash of the ...
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1answer
3k views

AES-CBC then SHA vs AES-GCM for encrypting and authenticating a web token

I am trying to have something like JWT but kinda ad hoc and encrypted. The token itself is simply a stringified JSON that contains the user ID and Unix timestamp. Now, I tried to use AES-128-GCM, ...
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1answer
105 views

Is symmetric encryption with a key containing the userId passes as authentication?

The scenario: There is a web application where ownership check is time expensive so during the development all users were able to access all other user's objects (let's say apples) by changing the ...
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1answer
6k views

HMAC-SHA256 vs HMAC-SHA512 for JWT API authentication

Which algorithm is recommended to use when encoding / decoding JWT web application tokens? Is using HMAC-SHA256 enough or would using ...
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1answer
404 views

sign data and append certificate VS sign data and certificate

I am currently writing my masters thesis in which I need to develop a licensing module for an application. The license itself is a JSON Web Token which is signed using a RSA private key. Since we ...
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410 views

JWT Common Practices

I had a few questions in regards to certain practices used by JWT developers. I'm relatively new to both encryption and JWTs and the context given is for developing a system on nodejs. How should ...
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1answer
692 views

Compromise between HMAC and Digital Signature, by encrypting and sending secret key?

For achieving stateless authentication tokens (like JWT), is there a compromise between the performance of HMAC, and public key distribution of Digital Signature? Scenario: Sender is a centralized ...
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2answers
11k views

HMAC vs ECDSA for JWT

I will be implementing JSON web tokens into my website and have a question about implementing them. I have a choice of using two algorithms, HMAC-SHA256 and ECDSA-SHA256. I have used HMAC-SHA256 in ...
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3k views

what are the advatanges and disavantages of the digital signature algorithms for JWT?

I am using a Java JWT library jose4j. There is a list of digital signatures algorithms which can be used. HMAC using SHA-2 RSASSA-PKCS1-V1_5 Digital Signatures with with SHA-2 Elliptic Curve Digital ...
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2answers
502 views

Padding to increase entropy and size of (otherwise) small JSON objects

Maybe this better fits, the security stackexchange... I'm building a web API. We want to enable some relatively simple encryption, instead of going full-blown OAuth2 (which frankly, IMO, sucks). So I ...