1 // This file was extracted from the TCG Published
2 // Trusted Platform Module Library
3 // Part 3: Commands
4 // Family "2.0"
5 // Level 00 Revision 01.16
6 // October 30, 2014
7
8 #include "InternalRoutines.h"
9 #include "ECDH_KeyGen_fp.h"
10 #ifdef TPM_ALG_ECC
11 //
12 //
13 // Error Returns Meaning
14 //
15 // TPM_RC_ATTRIBUTES If the key is restricted or the key is not a decryption key
16 // TPM_RC_KEY keyHandle does not reference a non-restricted decryption ECC key
17 //
18 TPM_RC
TPM2_ECDH_KeyGen(ECDH_KeyGen_In * in,ECDH_KeyGen_Out * out)19 TPM2_ECDH_KeyGen(
20 ECDH_KeyGen_In *in, // IN: input parameter list
21 ECDH_KeyGen_Out *out // OUT: output parameter list
22 )
23 {
24 OBJECT *eccKey;
25 TPM2B_ECC_PARAMETER sensitive;
26 TPM_RC result;
27
28 // Input Validation
29
30 eccKey = ObjectGet(in->keyHandle);
31
32 // Input key must be a non-restricted, decrypt ECC key
33 if( eccKey->publicArea.type != TPM_ALG_ECC)
34 return TPM_RC_KEY + RC_ECDH_KeyGen_keyHandle;
35
36 if( eccKey->publicArea.objectAttributes.restricted == SET
37 || eccKey->publicArea.objectAttributes.decrypt != SET
38 )
39 return TPM_RC_ATTRIBUTES + RC_ECDH_KeyGen_keyHandle;
40
41 // Command Output
42 do
43 {
44 // Create ephemeral ECC key
45 CryptNewEccKey(eccKey->publicArea.parameters.eccDetail.curveID,
46 &out->pubPoint.t.point, &sensitive);
47
48 out->pubPoint.t.size = TPMS_ECC_POINT_Marshal(&out->pubPoint.t.point,
49 NULL, NULL);
50
51 // Compute Z
52 result = CryptEccPointMultiply(&out->zPoint.t.point,
53 eccKey->publicArea.parameters.eccDetail.curveID,
54 &sensitive, &eccKey->publicArea.unique.ecc);
55 // The point in the key is not on the curve. Indicate that the key is bad.
56 if(result == TPM_RC_ECC_POINT)
57 return TPM_RC_KEY + RC_ECDH_KeyGen_keyHandle;
58 // The other possible error is TPM_RC_NO_RESULT indicating that the
59 // multiplication resulted in the point at infinity, so get a new
60 // random key and start over (hardly ever happens).
61 }
62 while(result == TPM_RC_NO_RESULT);
63
64 if(result == TPM_RC_SUCCESS)
65 // Marshal the values to generate the point.
66 out->zPoint.t.size = TPMS_ECC_POINT_Marshal(&out->zPoint.t.point,
67 NULL, NULL);
68
69 return result;
70 }
71 #endif
72