Tagged Questions
2
votes
1answer
79 views
is pkcs#7 suitable for signing and encrypting zip files?
I'm looking to protect zip files that I will be regularly sending to a 3rd party.
I need to ensure strong confidentiality and non-repudation. I would like signing/encryption to be based on ...
3
votes
1answer
148 views
how to specify pkcs#7 requirements for a third party you are exchanging data with?
I am looking to use PKCS#7 to sign and encrypt data (offline batch data files) that are exchanged with a 3rd party.
I need to write an interface specification for the 3rd party so that they can ...
1
vote
4answers
102 views
certificate usage for signing and encryption
I have a question for basic operating with certificates in emails and pdfs. Im familiar with public key cryptography.
The scenario:
In my scenario I want to send a confidential email to a person A ...
1
vote
1answer
96 views
PKCS#7 message constructed by our code, any weaknesses in the output?
We have this as the PKCS#7 encrypted message. We would like to open this up for review and analysis here, for people to poke holes. This sample is generated via test certificates and keys. The concern ...
5
votes
1answer
186 views
Most efficient key algorithm for a TLS server key?
Let's assume I want to setup a HTTPS service on a modern-but-no-so-speedy x86 server without any form of hardware cryptographic accelerator.
Which key algorithm should I choose for the server key in ...
2
votes
3answers
356 views
rsa encrypted hash == rsa signature
$ echo -n "1327943823" > test_ok.txt
$ openssl dgst -sha1 -binary -out test_ok.sha1 test_ok.txt
$ echo "GURbsl4CFPCG83RCZxsEpoRleXicXQhH1OC4Fk77b7EMj2g8aHUhD/L+sm
...
12
votes
6answers
742 views
Why not RSA-encrypt the entire document?
I have recently learned of a way for person B to verify that a document sent from person A is indeed from person A.
Person A gives Person B his public RSA key. This must be done reliably.
Person A ...
5
votes
3answers
240 views
Digital Signature and Verification?
AFAIK , When Alice wants to write a message to Bob -- she uses Bob's public key and encrypt the message - and then Bob - using his private key - use to decrypt it.
So public key is used to decrypt ...
5
votes
3answers
860 views
Can I use a private key as a public key and vice versa?
I have code to encrypt data using a public key and decrypt it using a private key. This is useful when a client wants to send data to a server and know that only the server can decrypt it.
But say I ...
2
votes
1answer
6k views
How to use OpenSSL generated keys in Java?
I have my pair of Public and Private keys and my certificate. Those where created in OpenSSL (why? because I was asked to do it in OpenSSL).
Now I want to use those things to make a Java app that ...
5
votes
1answer
282 views
OpenPGP Encryption / Decryption Process Using GnuPG
I want to know if my method of encryption can ensure the security of my data if my database was hacked as well as the authenticity of the data I am decrypting. I am using GnuPG's implementation of the ...
6
votes
5answers
3k views
What does “key with length of x bits” mean?
I'd like to know what it means to say "the cryptosystem C uses keys with a length of x bits". I do not understand what the bits length means... doesn't it depend on the encoding? The same word encodes ...
12
votes
2answers
396 views
Digital Certificate deployment: using two certs for each user?
At a large enterprise environment I have come across a deployment approach for Digital Certificates where each user is issued two (2) key pairs:
One for signing documents, emails, etc. that is ...
3
votes
1answer
79 views
A method for securely sharing centrally-stored documents among a changing set of users?
I believe it's possible to meet these requirements only if a third party is involved in a manual process. For example:
Each user is given the same public key
The private key resides offline at a ...
8
votes
3answers
439 views
Most widespread use of PGP after 20 years
Phil Zimmerman released PGP (Pretty Good Privacy) on June 5, 1991. As we examine the legacy of that far-sighted and brave act 20 years later, what are the most widespread and helpful uses of PGP ...
18
votes
3answers
3k views
Why should one not use the same asymmetric key for encryption as they do for signing?
In an answer to a question about RSA and PGP, PulpSpy noted this:
It is possible to generate an RSA key pair using GPG (for both encryption and signing -- you should not use the same key for ...
11
votes
1answer
266 views
What are the problems with encrypted but unsigned data?
In another question's answer, D.W. wrote:
Make sure there is authenticity protection for the encrypted data (e.g., encrypt and then sign/MAC): you will need both confidentiality and authenticity ...
