package plan9.auth; //// apply PKCS#1 encoding to a hash value before an RSA public-key operation//// adapted from spki.b import java.util.Arrays; public class Pkcs1 { // // pkcs1 asn.1 DER encodings // static final byte[] pkcs1_md5_pfx = { (byte)0x30, (byte)32, // SEQUENCE in 32 bytes (byte)0x30, (byte)12, // SEQUENCE in 12 bytes (byte)6, (byte)8, // OBJECT IDENTIFIER in 8 bytes (byte)(40*1+2), // iso(1) member-body(2) (byte)(0x80 + 6), (byte)72, // US(840) (byte)(0x80 + 6), (byte)(0x80 + 119), (byte)13, // rsadsi(113549) (byte)2, // digestAlgorithm(2) (byte)5, // md5(5), end of OBJECT IDENTIFIER (byte)0x05, (byte)0, // NULL parameter, end of SEQUENCE (byte)0x04, (byte)16 //OCTET STRING in 16 bytes (MD5 length) } ; static final byte[] pkcs1_sha1_pfx = { (byte)0x30, (byte)33, // SEQUENCE in 33 bytes (byte)0x30, (byte)9, // SEQUENCE in 9 bytes (byte)6, (byte)5, // OBJECT IDENTIFIER in 5 bytes (byte)(40*1+3), // iso(1) member-body(3) (byte)14, // ??(14) (byte)3, // ??(3) (byte)2, // digestAlgorithm(2) (byte)26, // sha1(26), end of OBJECT IDENTIFIER (byte)0x05, (byte)0, // NULL parameter, end of SEQUENCE (byte)0x40, (byte)20 // OCTET STRING in 20 bytes (SHA1 length) }; // // mlen should be key length in bytes // public static final byte[] pkcs1_encode(String ha, byte[] hash, int mlen) throws CryptoError { // apply hash function to message byte[] prefix; if(ha.equals("md5")) prefix = pkcs1_md5_pfx; else if(ha.equals("sha") || ha.equals("sha1")) prefix = pkcs1_sha1_pfx; else throw new CryptoError("invalid hash algorithm: "+ha); int tlen = prefix.length + hash.length; if(mlen < tlen + 11) throw new CryptoError("intended encoded message length too short"); // add the wizard ASN.1 crud and the pad int pslen = mlen - tlen - 3; byte[] out = new byte[mlen]; out[0] = (byte)0; out[1] = (byte)1; Arrays.fill(out, 2, 2+pslen, (byte)0xFF); out[2+pslen] = (byte)0; System.arraycopy(prefix, 0, out, 2+pslen+1, prefix.length); System.arraycopy(hash, 0, out, 2+pslen+1+prefix.length, hash.length); return out; }}
package plan9.auth;
//
// apply PKCS#1 encoding to a hash value before an RSA public-key operation
//
// adapted from spki.b
import java.util.Arrays;
public class Pkcs1 {
//
// pkcs1 asn.1 DER encodings
//
static final byte[] pkcs1_md5_pfx = {
(byte)0x30, (byte)32, // SEQUENCE in 32 bytes
(byte)0x30, (byte)12, // SEQUENCE in 12 bytes
(byte)6, (byte)8, // OBJECT IDENTIFIER in 8 bytes
(byte)(40*1+2), // iso(1) member-body(2)
(byte)(0x80 + 6), (byte)72, // US(840)
(byte)(0x80 + 6), (byte)(0x80 + 119), (byte)13, // rsadsi(113549)
(byte)2, // digestAlgorithm(2)
(byte)5, // md5(5), end of OBJECT IDENTIFIER
(byte)0x05, (byte)0, // NULL parameter, end of SEQUENCE
(byte)0x04, (byte)16 //OCTET STRING in 16 bytes (MD5 length)
} ;
static final byte[] pkcs1_sha1_pfx = {
(byte)0x30, (byte)33, // SEQUENCE in 33 bytes
(byte)0x30, (byte)9, // SEQUENCE in 9 bytes
(byte)6, (byte)5, // OBJECT IDENTIFIER in 5 bytes
(byte)(40*1+3), // iso(1) member-body(3)
(byte)14, // ??(14)
(byte)3, // ??(3)
(byte)2, // digestAlgorithm(2)
(byte)26, // sha1(26), end of OBJECT IDENTIFIER
(byte)0x05, (byte)0, // NULL parameter, end of SEQUENCE
(byte)0x40, (byte)20 // OCTET STRING in 20 bytes (SHA1 length)
};
//
// mlen should be key length in bytes
//
public static final byte[] pkcs1_encode(String ha, byte[] hash, int mlen) throws CryptoError {
// apply hash function to message
byte[] prefix;
if(ha.equals("md5"))
prefix = pkcs1_md5_pfx;
else if(ha.equals("sha") || ha.equals("sha1"))
prefix = pkcs1_sha1_pfx;
else
throw new CryptoError("invalid hash algorithm: "+ha);
int tlen = prefix.length + hash.length;
if(mlen < tlen + 11)
throw new CryptoError("intended encoded message length too short");
// add the wizard ASN.1 crud and the pad
int pslen = mlen - tlen - 3;
byte[] out = new byte[mlen];
out[0] = (byte)0;
out[1] = (byte)1;
Arrays.fill(out, 2, 2+pslen, (byte)0xFF);
out[2+pslen] = (byte)0;
System.arraycopy(prefix, 0, out, 2+pslen+1, prefix.length);
System.arraycopy(hash, 0, out, 2+pslen+1+prefix.length, hash.length);
return out;
}
}