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+/********************************************************************************/
+/* */
+/* Ephemeral EC Keys */
+/* Written by Ken Goldman */
+/* IBM Thomas J. Watson Research Center */
+/* $Id: EphemeralCommands.c 1490 2019-07-26 21:13:22Z kgoldman $ */
+/* */
+/* Licenses and Notices */
+/* */
+/* 1. Copyright Licenses: */
+/* */
+/* - Trusted Computing Group (TCG) grants to the user of the source code in */
+/* this specification (the "Source Code") a worldwide, irrevocable, */
+/* nonexclusive, royalty free, copyright license to reproduce, create */
+/* derivative works, distribute, display and perform the Source Code and */
+/* derivative works thereof, and to grant others the rights granted herein. */
+/* */
+/* - The TCG grants to the user of the other parts of the specification */
+/* (other than the Source Code) the rights to reproduce, distribute, */
+/* display, and perform the specification solely for the purpose of */
+/* developing products based on such documents. */
+/* */
+/* 2. Source Code Distribution Conditions: */
+/* */
+/* - Redistributions of Source Code must retain the above copyright licenses, */
+/* this list of conditions and the following disclaimers. */
+/* */
+/* - Redistributions in binary form must reproduce the above copyright */
+/* licenses, this list of conditions and the following disclaimers in the */
+/* documentation and/or other materials provided with the distribution. */
+/* */
+/* 3. Disclaimers: */
+/* */
+/* - THE COPYRIGHT LICENSES SET FORTH ABOVE DO NOT REPRESENT ANY FORM OF */
+/* LICENSE OR WAIVER, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, WITH */
+/* RESPECT TO PATENT RIGHTS HELD BY TCG MEMBERS (OR OTHER THIRD PARTIES) */
+/* THAT MAY BE NECESSARY TO IMPLEMENT THIS SPECIFICATION OR OTHERWISE. */
+/* Contact TCG Administration (admin@trustedcomputinggroup.org) for */
+/* information on specification licensing rights available through TCG */
+/* membership agreements. */
+/* */
+/* - THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO EXPRESS OR IMPLIED */
+/* WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR */
+/* FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, COMPLETENESS, OR */
+/* NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, OR ANY WARRANTY */
+/* OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. */
+/* */
+/* - Without limitation, TCG and its members and licensors disclaim all */
+/* liability, including liability for infringement of any proprietary */
+/* rights, relating to use of information in this specification and to the */
+/* implementation of this specification, and TCG disclaims all liability for */
+/* cost of procurement of substitute goods or services, lost profits, loss */
+/* of use, loss of data or any incidental, consequential, direct, indirect, */
+/* or special damages, whether under contract, tort, warranty or otherwise, */
+/* arising in any way out of use or reliance upon this specification or any */
+/* information herein. */
+/* */
+/* (c) Copyright IBM Corp. and others, 2016 - 2019 */
+/* */
+/********************************************************************************/
+
+#include "Tpm.h"
+#include "Commit_fp.h"
+#if CC_Commit // Conditional expansion of this file
+TPM_RC
+TPM2_Commit(
+ Commit_In *in, // IN: input parameter list
+ Commit_Out *out // OUT: output parameter list
+ )
+{
+ OBJECT *eccKey;
+ TPMS_ECC_POINT P2;
+ TPMS_ECC_POINT *pP2 = NULL;
+ TPMS_ECC_POINT *pP1 = NULL;
+ TPM2B_ECC_PARAMETER r;
+ TPM2B_ECC_PARAMETER p;
+ TPM_RC result;
+ TPMS_ECC_PARMS *parms;
+ // Input Validation
+ eccKey = HandleToObject(in->signHandle);
+ parms = &eccKey->publicArea.parameters.eccDetail;
+ // Input key must be an ECC key
+ if(eccKey->publicArea.type != TPM_ALG_ECC)
+ return TPM_RCS_KEY + RC_Commit_signHandle;
+ // This command may only be used with a sign-only key using an anonymous
+ // scheme.
+ // NOTE: a sign + decrypt key has no scheme so it will not be an anonymous one
+ // and an unrestricted sign key might no have a signing scheme but it can't
+ // be use in Commit()
+ if(!CryptIsSchemeAnonymous(parms->scheme.scheme))
+ return TPM_RCS_SCHEME + RC_Commit_signHandle;
+ // Make sure that both parts of P2 are present if either is present
+ if((in->s2.t.size == 0) != (in->y2.t.size == 0))
+ return TPM_RCS_SIZE + RC_Commit_y2;
+ // Get prime modulus for the curve. This is needed later but getting this now
+ // allows confirmation that the curve exists.
+ if(!CryptEccGetParameter(&p, 'p', parms->curveID))
+ return TPM_RCS_KEY + RC_Commit_signHandle;
+ // Get the random value that will be used in the point multiplications
+ // Note: this does not commit the count.
+ if(!CryptGenerateR(&r, NULL, parms->curveID, &eccKey->name))
+ return TPM_RC_NO_RESULT;
+ // Set up P2 if s2 and Y2 are provided
+ if(in->s2.t.size != 0)
+ {
+ TPM2B_DIGEST x2;
+ pP2 = &P2;
+ // copy y2 for P2
+ P2.y = in->y2;
+ // Compute x2 HnameAlg(s2) mod p
+ // do the hash operation on s2 with the size of curve 'p'
+ x2.t.size = CryptHashBlock(eccKey->publicArea.nameAlg,
+ in->s2.t.size,
+ in->s2.t.buffer,
+ sizeof(x2.t.buffer),
+ x2.t.buffer);
+ // If there were error returns in the hash routine, indicate a problem
+ // with the hash algorithm selection
+ if(x2.t.size == 0)
+ return TPM_RCS_HASH + RC_Commit_signHandle;
+ // The size of the remainder will be same as the size of p. DivideB() will
+ // pad the results (leading zeros) if necessary to make the size the same
+ P2.x.t.size = p.t.size;
+ // set p2.x = hash(s2) mod p
+ if(DivideB(&x2.b, &p.b, NULL, &P2.x.b) != TPM_RC_SUCCESS)
+ return TPM_RC_NO_RESULT;
+ if(!CryptEccIsPointOnCurve(parms->curveID, pP2))
+ return TPM_RCS_ECC_POINT + RC_Commit_s2;
+ if(eccKey->attributes.publicOnly == SET)
+ return TPM_RCS_KEY + RC_Commit_signHandle;
+ }
+ // If there is a P1, make sure that it is on the curve
+ // NOTE: an "empty" point has two UINT16 values which are the size values
+ // for each of the coordinates.
+ if(in->P1.size > 4)
+ {
+ pP1 = &in->P1.point;
+ if(!CryptEccIsPointOnCurve(parms->curveID, pP1))
+ return TPM_RCS_ECC_POINT + RC_Commit_P1;
+ }
+ // Pass the parameters to CryptCommit.
+ // The work is not done in-line because it does several point multiplies
+ // with the same curve. It saves work by not having to reload the curve
+ // parameters multiple times.
+ result = CryptEccCommitCompute(&out->K.point,
+ &out->L.point,
+ &out->E.point,
+ parms->curveID,
+ pP1,
+ pP2,
+ &eccKey->sensitive.sensitive.ecc,
+ &r);
+ if(result != TPM_RC_SUCCESS)
+ return result;
+ // The commit computation was successful so complete the commit by setting
+ // the bit
+ out->counter = CryptCommit();
+ return TPM_RC_SUCCESS;
+}
+#endif // CC_Commit
+#include "Tpm.h"
+#include "EC_Ephemeral_fp.h"
+#if CC_EC_Ephemeral // Conditional expansion of this file
+TPM_RC
+TPM2_EC_Ephemeral(
+ EC_Ephemeral_In *in, // IN: input parameter list
+ EC_Ephemeral_Out *out // OUT: output parameter list
+ )
+{
+ TPM2B_ECC_PARAMETER r;
+ TPM_RC result;
+ //
+ do
+ {
+ // Get the random value that will be used in the point multiplications
+ // Note: this does not commit the count.
+ if(!CryptGenerateR(&r, NULL, in->curveID, NULL))
+ return TPM_RC_NO_RESULT;
+ // do a point multiply
+ result = CryptEccPointMultiply(&out->Q.point, in->curveID, NULL, &r,
+ NULL, NULL);
+ // commit the count value if either the r value results in the point at
+ // infinity or if the value is good. The commit on the r value for infinity
+ // is so that the r value will be skipped.
+ if((result == TPM_RC_SUCCESS) || (result == TPM_RC_NO_RESULT))
+ out->counter = CryptCommit();
+ } while(result == TPM_RC_NO_RESULT);
+ return TPM_RC_SUCCESS;
+}
+#endif // CC_EC_Ephemeral
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