Hello, > I created EC keypair via JAVA with secp160r2 template. When I looked at text > form of public key, I saw there this: > > "04666d59b1fb53c1c998c12c71731d3a36a37cd995cadeee96c156c8d7c7852b39b5fefd1fa3ce18c7" > > I know that last 40 bytes present x and y number of ec point but I don't > know what means first byte 04. This means that this octet string has EC point (x,y) without compression.
> It's some compresion or what ? This is information how to interpret following octets. > Does exist some rule for generating of this byte or it's constant value ?. Yes, you may look at "SEC1: Elliptic Curve Cryptography" chapter 2.3.3, in short: 00 - point at inifinity 02 or 03 - compressed point (depending on EC point) 04 - uncompressed point > In Java I created public key that menas I know ec point(x and y) and now I > need to construct this array of 41 bytes If you are going to use uncompressed point then you should create octet string as 04|x|y (in hex). Best regards, -- Marek Marcola <[EMAIL PROTECTED]> ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager [EMAIL PROTECTED]
