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Jan
29
comment Should the most significant byte of a cryptograhic key be nonzero?
@fkraiem Thanks, made last section stronger
Jan
29
revised Should the most significant byte of a cryptograhic key be nonzero?
REmoved "even" twice, sounds somewhat demeaning. Made last point somewhat stronger after comment of fkraiem.
Jan
28
comment Is H'(M)=5*M + 9*H(M) mod 2^n a secure hash?
@DrLecter It feels much as an exercise to me. It's about reasoning and finding a counterexample.
Jan
28
answered Should the most significant byte of a cryptograhic key be nonzero?
Jan
28
comment Vulnerabilities in SHA-1
Space is a bit short here to repeat all the papers written about SHA-1. Your frequency analysis was bound to fail, but that tells absolutely nothing about the security or insecurity of SHA-1.
Jan
28
comment Is H'(M)=5*M + 9*H(M) mod 2^n a secure hash?
How is $H$ defined? I see a formal definition of $H'$ but not of $H$.
Jan
28
answered RSA-OAEP: How does it work?
Jan
28
comment Degrade in performance with SSL_OP_SINGLE_ECDH_USE?
For OpenSSL specific implementation / deployment questions you're better off at e.g. superuser or Unix).
Jan
27
comment How can a message encrypted with the public key be decrypted with the private key?
I think the title needs some work. Generally the plain text is encrypted with a public key and the resulting ciphertext is decrypted with a private key.
Jan
27
comment AES key and block size
@Mok-KongShen Could you turn that into an answer? "Read the standard" is not much of an answer in itself, but maybe you can quote the pseudo code? Otherwise I think the question has to be closed.
Jan
27
revised Forward Secrecy when using non-ephemeral DH
added 374 characters in body
Jan
27
revised Forward Secrecy when using non-ephemeral DH
added 374 characters in body
Jan
26
answered Forward Secrecy when using non-ephemeral DH
Jan
26
comment Forward Secrecy when using non-ephemeral DH
Indeed. If you'd use static-static DH a random is used to make sure that the session key is renewed each time a session is set up. In other words, the session key should always be ephemeral, regardless if forward secrecy is used.
Jan
25
revised What is wrong in the following algorithm for computing a hash function using RSA?
formatting
Jan
24
comment Using RSA key pair for file encryption
Note that currently you are using the symmetric session key as password. That also explains why the 256 byte "key" works: it is first converted using the BytesToKey function. It also explains why you don't need an IV - a salt is automatically inserted in front of the ciphertext (after a 8 byte magic).
Jan
24
comment Full encryption of IDs, partial decryption with customer specific key
My implementation using HKDF and Blowfish seems to work fine anyway - implemented some time after the comment :)
Jan
24
answered Full encryption of IDs, partial decryption with customer specific key
Jan
24
comment Full encryption of IDs, partial decryption with customer specific key
Are you allowed to send additional data to the customers, such as multiple $(n, data)$ pairs, where $n$ is just the index of an ID and $data$ is just any binary blob?
Jan
24
revised Full encryption of IDs, partial decryption with customer specific key
formatting, typing error, title