Re: Secure plaintext-derived filename [was: HMAC with RSA Key]

2011-10-26 Thread Jakob Bohm
On 10/26/2011 3:01 PM, Steffen DETTMER wrote: 4. Truncate the string to your desired file name length, but not so short that accidental collisions become likely (Example to keep up to 16000 file names likely different, use file names with 2 * log2(16000)=2*14=28 bits minimum). Where can I lear

RE: Secure plaintext-derived filename [was: HMAC with RSA Key]

2011-10-26 Thread Steffen DETTMER
> > 4. Truncate the string to your desired file name length, but not so > > short that accidental collisions become likely (Example to > > keep up to 16000 file names likely different, use file names with 2 * > > log2(16000)=2*14=28 bits minimum). Where can I learn more about this formula? I th

Re: Secure plaintext-derived filename [was: HMAC with RSA Key]

2011-10-25 Thread Jakob Bohm
SHA-1 is partially broken already. It should not be used unless necessary for backwards compatibility. On 10/25/2011 9:01 PM, Jonas Schnelli wrote: On 10/25/2011 10:52 AM, Jonas Schnelli wrote: How do i create a HMAC-SHA1 with a RSA Key? What do i give as input for the param *key? Why: M

Re: Secure plaintext-derived filename [was: HMAC with RSA Key]

2011-10-25 Thread Jonas Schnelli
> On 10/25/2011 10:52 AM, Jonas Schnelli wrote: >> How do i create a HMAC-SHA1 with a RSA Key? >> What do i give as input for the param *key? >> >> Why: >> My encrypted file has now the filename of the unencrypted-files-sha1. >> (unsecure!). >> I cannot use the sha1 of the encrypted file becau

Re: Secure plaintext-derived filename [was: HMAC with RSA Key]

2011-10-25 Thread Jonas Schnelli
> On 10/25/2011 10:52 AM, Jonas Schnelli wrote: >> How do i create a HMAC-SHA1 with a RSA Key? >> What do i give as input for the param *key? >> >> Why: >> My encrypted file has now the filename of the unencrypted-files-sha1. >> (unsecure!). >> I cannot use the sha1 of the encrypted file because

Re: Secure plaintext-derived filename [was: HMAC with RSA Key]

2011-10-25 Thread Jakob Bohm
On 10/25/2011 10:52 AM, Jonas Schnelli wrote: How do i create a HMAC-SHA1 with a RSA Key? What do i give as input for the param *key? Why: My encrypted file has now the filename of the unencrypted-files-sha1. (unsecure!). I cannot use the sha1 of the encrypted file because i use EVP_Seal* (aes2

HMAC with RSA Key

2011-10-25 Thread Jonas Schnelli
Hi How do i create a HMAC-SHA1 with a RSA Key? What do i give as input for the param *key? Why: My encrypted file has now the filename of the unencrypted-files-sha1. (unsecure!). I cannot use the sha1 of the encrypted file because i use EVP_Seal* (aes256 session key) so the sha1 of the encrypte