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May
19
revised Building a combined encryption scheme from two encryption schemes that's secure if at least on of them is secure
rolled back to a previous revision
May
19
comment Is it possible to encrypt x coordinate of an EC point with a password?
You can encrypt arbitrary byte sequences using password based encryption. You can encode EC points as byte sequences. So you can obviously encrypt EC points with a password. But I don't know how PAKE fits into that picture.
May
18
comment Does Ed25519 support cryptographic threshold signatures?
Ed25519 includes $R$ in the message hash. Does that cause problems for the threshold scheme?
May
18
revised Inversion Free Direct Conversion between Twisted Edwards (X,Y,Z) and Montgomery (X,Z)
added 133 characters in body
May
18
answered Inversion Free Direct Conversion between Twisted Edwards (X,Y,Z) and Montgomery (X,Z)
May
11
comment ECC vs RSA: how to compare key sizes?
1) The number can't be right. 2048 bits RSA roughly corresponds to a 112 bit symmetric key or a 224 bit ECC key. 2) You wrote a + in the RSA formula where it should be a *. 3) The RSA formula is asymptotic, but you need concrete cost for the comparison.
May
9
comment RSA: How to calculate the private exponent?
You could factor $n$. 33=3*11
May
8
comment Question about discrete log - why can one attacker not solve for g but two colluders can?
Isn't this question about roots, not logarithms?
May
7
revised Why does Diffie-Hellman need be a cyclic group?
added 4 characters in body; edited tags; edited title
May
7
comment Algorithm for n-of-m keys with partial results
If you use a one-time key, then being trusted to hold that one time key is equivalent to being trusted to hold the plaintext. Then secret-share the one-time key and encrypt the shares with the public keys of the share holders.
May
7
comment Key Check Value standard pratice for asymetric cryptography?
For your secret sharing scenario my first instinct is using an all-or-nothing transform on the plaintext together with some redundancy, similar to OAEP. Should probably the unkeyed equivalent of a strong pseudo-random-permutation.
May
7
comment Key Check Value standard pratice for asymetric cryptography?
Public key fingerprints are used by SSH (and other protocols).
May
7
comment Why does Diffie-Hellman need be a cyclic group?
Related questions: Diffie-Hellman on infinite groups and How does the wider cryptographic community view non-abelian group based cryptography?
May
6
comment Is encryption time greater than decryption time?
RSA decryption is much slower than encryption. For AES and DES it should be roughly the same. No clue what DNA is.
May
4
comment Encrypting and Decrypting a 19-digits long BigInteger
Do you need to support any 19 digit integer? Or is the input limited to 64 bits?
May
4
comment What are the vulnerabilities of this homemade encryption algorithm?
I'm voting to close this question as off-topic because it's about breaking a homebrew cipher.
May
4
reviewed Reviewed RFC 5297 implementation
May
4
reviewed Reviewed Can I submit an encrypted message to see if its breakable here?
May
4
comment Can I submit an encrypted message to see if its breakable here?
I'm voting to close this question as off-topic because it's about breaking a homebrew cipher.
May
4
comment Can I submit an encrypted message to see if its breakable here?
Nowadays we expect much more of ciphers. In particular they much not leak any information about the plaintext, apart from its length. It must be secure even if the attacker knows (or even chooses) part of the plaintext, etc. No attack must be significantly faster that brute-force. It shouldn't be limited to letters, but should work with arbitrary bytes.