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diff --git a/libtomcrypt/notes/tech0006.txt b/libtomcrypt/notes/tech0006.txt new file mode 100644 index 0000000..ecbe8b0 --- /dev/null +++ b/libtomcrypt/notes/tech0006.txt @@ -0,0 +1,91 @@ +Tech Note 0006 +PK Standards Compliance +Tom St Denis + +RSA +---- + +PKCS #1 compliance. + +Key Format: RSAPublicKey and RSAPrivateKey as per PKCS #1 v2.1 +Encryption: OAEP as per PKCS #1 +Signature : PSS as per PKCS #1 + +DSA +---- + +The NIST DSA algorithm + +Key Format: HomeBrew [see below] +Signature : ANSI X9.62 format [see below]. + +Keys are stored as + +DSAPublicKey ::= SEQUENCE { + publicFlags BIT STRING(1), -- must be 0 + g INTEGER , -- base generator, check that g^q mod p == 1 + -- and that 1 < g < p - 1 + p INTEGER , -- prime modulus + q INTEGER , -- order of sub-group (must be prime) + y INTEGER , -- public key, specifically, g^x mod p, + -- check that y^q mod p == 1 + -- and that 1 < y < p - 1 +} + +DSAPrivateKey ::= SEQUENCE { + publicFlags BIT STRING(1), -- must be 1 + g INTEGER , -- base generator, check that g^q mod p == 1 + -- and that 1 < g < p - 1 + p INTEGER , -- prime modulus + q INTEGER , -- order of sub-group (must be prime) + y INTEGER , -- public key, specifically, g^x mod p, + -- check that y^q mod p == 1 + -- and that 1 < y < p - 1 + x INTEGER -- private key +} + +Signatures are stored as + +DSASignature ::= SEQUENCE { + r, s INTEGER -- signature parameters +} + +ECC +---- + +The ANSI X9.62 and X9.63 algorithms [partial]. Supports all NIST GF(p) curves. + +Key Format : Homebrew [see below, only GF(p) NIST curves supported] +Signature : X9.62 compliant +Encryption : Homebrew [based on X9.63, differs in that the public point is stored as an ECCPublicKey] +Shared Secret: X9.63 compliant + +ECCPublicKey ::= SEQUENCE { + flags BIT STRING(1), -- public/private flag (always zero), + keySize INTEGER, -- Curve size (in bits) divided by eight + -- and rounded down, e.g. 521 => 65 + pubkey.x INTEGER, -- The X co-ordinate of the public key point + pubkey.y INTEGER, -- The Y co-ordinate of the public key point +} + +ECCPrivateKey ::= SEQUENCE { + flags BIT STRING(1), -- public/private flag (always one), + keySize INTEGER, -- Curve size (in bits) divided by eight + -- and rounded down, e.g. 521 => 65 + pubkey.x INTEGER, -- The X co-ordinate of the public key point + pubkey.y INTEGER, -- The Y co-ordinate of the public key point + secret.k INTEGER, -- The secret key scalar +} + +The encryption works by finding the X9.63 shared secret and hashing it. The hash is then simply XOR'ed against the message [which must be at most the size +of the hash digest]. The format of the encrypted text is as follows + +ECCEncrypted ::= SEQUENCE { + hashOID OBJECT IDENTIFIER, -- The OID of the hash used + pubkey OCTET STRING , -- Encapsulation of a random ECCPublicKey + skey OCTET STRING -- The encrypted text (which the hash was XOR'ed against) +} + +% $Source: /cvs/libtom/libtomcrypt/notes/tech0006.txt,v $ +% $Revision: 1.2 $ +% $Date: 2005/06/18 02:26:27 $ |