Ok. I am a little bit confused. You are telling me that a same data encrypted with the same key can generate different results? How can the decryption process can succeed ?!
Maybe it's my cryto knowledge that are limited, but I was sure that one output correspond to one input. I run my tests couples of time and it always gives me the same output result each times (meaning that the peuso-random generator always gives the same number?). You are probably right, but could you confirm me that my tests are made correctly (using a longer array than the size passed to the encryption function) ? Dr. Stephen Henson wrote: > > On Mon, Dec 15, 2008, BiGNoRm6969 wrote: > >> >> Hi, the OpenSSL documentation tells : >> >> "RSA_public_encrypt() encrypts the flen bytes at from (usually a session >> key) using the public key rsa and stores the ciphertext in to. to must >> point >> to RSA_size(rsa) bytes of memory. " >> >> >> I made a test and I saw something strange. I used theses arrays for my >> tests: >> >> unsigned char* test1 = new unsigned char[5]; >> test1[0] = 'a'; >> test1[1] = 'b'; >> test1[2] = 'c'; >> test1[3] = 'd'; >> test1[4] = 'e'; >> >> unsigned char* test2 = new unsigned char[4]; >> test2[0] = 'a'; >> test2[1] = 'b'; >> test2[2] = 'c'; >> test2[3] = 'd'; >> >> >> Here is my test: >> >> RSA_public_encrypt(4, test1, encryptedLine1, publicKey, >> RSA_PKCS1_PADDING); >> RSA_public_encrypt(4, test2, encryptedLine2, publicKey, >> RSA_PKCS1_PADDING); >> >> The two results (stored in encryptedLineX...) are not the same and I >> don't >> understand why. The first argument is not supposed to be the length (in >> bytes) of the data to be encrypted ? So in the two cases, the encryption >> is >> not supposed to bo on caracter 1 to 4 !? >> > > This is expected behaviour and is due to the nature of that padding mode. > It > includes some pseudo random data which is different on each invocation. So > even if you encrypt the same data using the same key you will get a > different > output each time. > > Steve. > -- > Dr Stephen N. Henson. Email, S/MIME and PGP keys: see homepage > OpenSSL project core developer and freelance consultant. > Homepage: http://www.drh-consultancy.demon.co.uk > ______________________________________________________________________ > OpenSSL Project http://www.openssl.org > User Support Mailing List openssl-users@openssl.org > Automated List Manager majord...@openssl.org > > -- View this message in context: http://www.nabble.com/RSA_public_encrypt%28%29-strange-result-output...-is-it-a-bug-%21--tp21022467p21032487.html Sent from the OpenSSL - User mailing list archive at Nabble.com. ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
