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tor-spec patch from adam langley

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svn:r4439
This commit is contained in:
Roger Dingledine 2005-06-16 20:33:03 +00:00
parent 5c85d97496
commit 3961683571
1 changed files with 16 additions and 14 deletions
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doc/tor-spec.txt
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@ -31,8 +31,9 @@ TODO: (very soon)
Unless otherwise specified, all symmetric ciphers are AES in counter Unless otherwise specified, all symmetric ciphers are AES in counter
mode, with an IV of all 0 bytes. Asymmetric ciphers are either RSA mode, with an IV of all 0 bytes. Asymmetric ciphers are either RSA
with 1024-bit keys and exponents of 65537, or DH with the safe prime with 1024-bit keys and exponents of 65537, or DH where the generator
from rfc2409, section 6.2, whose hex representation is: is 2 and the modulus is the safe prime from rfc2409, section 6.2,
whose hex representation is:
"FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08" "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E08"
"8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B" "8A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B"
@ -43,7 +44,7 @@ TODO: (very soon)
All "hashes" are 20-byte SHA1 cryptographic digests. All "hashes" are 20-byte SHA1 cryptographic digests.
When we refer to "the hash of a public key", we mean the SHA1 hash of the When we refer to "the hash of a public key", we mean the SHA1 hash of the
ASN.1 encoding of an RSA public key (as specified in PKCS.1). DER encoding of an ASN.1 RSA public key (as specified in PKCS.1).
1. System overview 1. System overview
@ -71,9 +72,9 @@ TODO: (very soon)
least 128 bits, and digests of at least 160 bits. least 128 bits, and digests of at least 160 bits.
An OP or OR always sends a two-certificate chain, consisting of a An OP or OR always sends a two-certificate chain, consisting of a
self-signed certificate containing the OR's identity key, and a second certificate using a short-term connection key and a second, self-
certificate using a short-term connection key. The commonName of the signed certificate containing the OR's identity key. The commonName of the
second certificate is the OR's nickname, and the commonName of the first first certificate is the OR's nickname, and the commonName of the second
certificate is the OR's nickname, followed by a space and the string certificate is the OR's nickname, followed by a space and the string
"<identity>". "<identity>".
@ -164,13 +165,14 @@ TODO: (very soon)
The payload for a CREATE cell is an 'onion skin', which consists The payload for a CREATE cell is an 'onion skin', which consists
of the first step of the DH handshake data (also known as g^x). of the first step of the DH handshake data (also known as g^x).
The data is encrypted to Bob's PK as follows: Suppose Bob's PK is The data is encrypted to Bob's PK as follows: Suppose Bob's PK
L octets long. If the data to be encrypted is shorter than L-42, modulus is L octets long. If the data to be encrypted is shorter
then it is encrypted directly (with OAEP padding). If the data is at than L-42, then it is encrypted directly (with OAEP padding: see
least as long as L-42, then a randomly generated 16-byte symmetric ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.pdf). If the
key is prepended to the data, after which the first L-16-42 bytes data is at least as long as L-42, then a randomly generated 16-byte
of the data are encrypted with Bob's PK; and the rest of the data is symmetric key is prepended to the data, after which the first L-16-42
encrypted with the symmetric key. bytes of the data are encrypted with Bob's PK; and the rest of the
data is encrypted with the symmetric key.
So in this case, the onion skin on the wire looks like: So in this case, the onion skin on the wire looks like:
RSA-encrypted: RSA-encrypted:
@ -265,7 +267,7 @@ TODO: (very soon)
router's exit policy does not exclude all pending streams router's exit policy does not exclude all pending streams
that need a circuit. that need a circuit.
2. Choose a chain of (N-1) chain of N onion routers 2. Choose a chain of (N-1) onion routers
(R_1...R_N-1) to constitute the path, such that no router (R_1...R_N-1) to constitute the path, such that no router
appears in the path twice. appears in the path twice.