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  • 7 votes cast
Sep
26
comment Digital signatures using a partially public key
I see. In 2006, RFC 4635 calls for 96 bit truncation. I believe the recommendation is to increase by 16 bits a decade. So how about SHA-1 truncated to 112 bits?
Sep
26
comment Digital signatures using a partially public key
@MaartenBodewes How come? HMAC can be done using MD5 - right? Yes, it's not as secure as SHA-1 as user595228 pointed out. Rather than MD5, I'm thinking to use SHA-1 and output 112 bit truncation. In 2006, RFC 4635 calls for 96 bit truncation. With +16 bits a decade, should 112 bit truncation be secure (for packets that live for 1 hour)?
Sep
25
comment Digital signatures using a partially public key
Is XOR of a public and a private more secure than concatenating the private key and a KDF derived key using the public?
Sep
25
comment Digital signatures using a partially public key
Sure. But isn't it the case for all symmetric key digital signatures? Compute the hash of the message and match against the signature.
Sep
25
revised Digital signatures using a partially public key
added 9 characters in body; added 159 characters in body
Sep
25
comment Digital signatures using a partially public key
The signature is for verifying that the message is authentic. The same private key will be hard coded in all devices, so the threat model is that someone holding onto a device knowing someone else's public key could fool the master about the authenticity of the messages. Verifying the signature isn't so harmful here; I'm hoping to defeat the threat of spoofing signatures.
Sep
25
revised Digital signatures using a partially public key
added 26 characters in body; added 61 characters in body; added 1 character in body; added 65 characters in body
Sep
25
asked Digital signatures using a partially public key
Sep
24
comment Avoiding replay attack on certified announcements
Yes, the salt is kept private - hard coded in all agents. So the KDF derives keys from a salted master key.
Sep
24
comment Avoiding replay attack on certified announcements
I see. Will it still be secure if the master key, which after being salted is used derive a key to sign messages, is shared over a public channel?
Sep
24
asked Avoiding replay attack on certified announcements
Sep
23
accepted Practical benefit of using a KDF?
Sep
23
asked Practical benefit of using a KDF?
Sep
21
awarded  Curious
Sep
20
awarded  Yearling
Sep
20
accepted Is ChaCha20 alone sufficient for securing data-at-rest?
Sep
20
comment Is ChaCha20 alone sufficient for securing data-at-rest?
@CodesInChaos Why won't plain, unencrypted checksum do here though?
Sep
20
comment Is ChaCha20 alone sufficient for securing data-at-rest?
@CodesInChaos Right. But checksum not address that?
Sep
20
comment Is ChaCha20 alone sufficient for securing data-at-rest?
@CodeInChaos Sorry, but how does cloud backup change the threat model if the file itself is already securely encrypted?
Sep
20
asked Is ChaCha20 alone sufficient for securing data-at-rest?