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Sep
19
awarded  Popular Question
Dec
18
comment RSA blind signatures in practice
Please consider rdist.root.org/2009/10/06/… It is stated that "Failure to properly manage RSA armoring could allow attackers to forge signatures, decrypt ciphertext, or even recover your private key."
Dec
14
comment RSA blind signatures in practice
It seems that we are really close to the point :) If a bank uses the blinding key only for blinding (not encryption or ordinary signatures) is it safe for a bank to perform signature over the plain textbook with this "blind" key? Since attacker may supply blinded version of m = 2, or m = 3 (i.e. $Blinded\ version\ of\ message = 2 \cdot r^{e}$), which I'm afraid (I don't actually know) may leak the private encryption exponent? Or it is not possible when keys are chosen properly and have lengths around 4096 bits?
Dec
12
comment RSA blind signatures in practice
But in that case bank is open to "RSA blinding attack", please check en.wikipedia.org/wiki/Blind_signature#Dangers_of_blind_signing
Dec
12
comment RSA blind signatures in practice
I don't need to unpad a message, the problem is that the padding is applied by the signer, to prevent fraud, and when the signer pads the blind signature, he destroys it...
Dec
11
revised RSA blind signatures in practice
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Dec
11
comment RSA blind signatures in practice
As far as I understood the whole process, there are two sides A - Applicant, B - Bank. For example Applicant creates a token that represents 10\$ with serial number AH43S, then Applicant blinds the token with random R so that the Bank is not able to discover token's serial number. Then applicant sends blinded token to Bank, and asks it to sign with 10\$ key. Now Bank needs to pad a blinded version of token, to prevent any attacks on it's key, and after the blinded token is padded there is no way to unblind it...
Dec
9
awarded  Student
Dec
8
awarded  Editor
Dec
8
revised RSA blind signatures in practice
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Dec
8
asked RSA blind signatures in practice