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5

RFC 4880, OpenPGP (superseded RFC 2440 which was up to date in 2002) contains a chapter on security considerations, which also discusses the decryption oracle attack Jallad et al described: In late summer 2002, Jallad, Katz, and Schneier published an interesting attack on the OpenPGP protocol and some of its implementations [JKS02]. In ...


3

This is actually a rather interesting question, whiches solution is obvious to all cryptographers but I guess nobody cared yet to write it down. After all, our computers who are generating secret keys (not just GPG / RSA) are deterministic machines. These deterministic machines implement well-defined routines to generate keys of well-defined format which ...


2

I would not consider your case to be a cascading encryption. The reason why is the fact you need multiple interventions before getting access to your file. Here is what I would consider a cascading encryption (let's go crazy) : $$E(k_1,k_2,k_3,m) = \text{KEYAK}(k_1,\text{NORX}(k_2,\text{AES}(k_3,m)))$$ which you would decipher with : ...


1

The padding used for RSA is not the PKCS #5/#7 padding (as you seem to suggest in your own answer), but the Wikipedia entry seems to refer to PKCS #1 v1.5 (RFC2313)) which uses a padding 00 || BT || PS || 00 || D where for RSA encryption we start with a 0x00-byte (to guarantee that the resulting number is below the modulus), then use BT (Block Type) equal ...


1

TL;DR: This attack extends the standard chosen ciphertext attacks on RSA and ElGamal to the hybrid encryption setting, but requires some huge IFs which no longer even have a slight possibility of being fulfilled. To understand this attack, one first needs to understand how data is encrypted for PGP according to this snippet. Let's assume you have a ...



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