Squashed commit of the following:

commit 942aed8a4e7c173a2c9423829c2b38087cbd49e4
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Aug 6 20:54:03 2024 -0400

    chore: update changelog and mbedtls headers

commit 3b97f84fd0477eafcd6567eb8597b213e4136664
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Aug 6 19:57:10 2024 -0400

    update libsecp256k1 to v0.5.1

commit 7989a2660997b909e0b99fc1dfb3bcfbb0528df3
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Aug 6 19:42:25 2024 -0400

    update openssl to 3.3.1

commit e949ae5aa1fd25d4d11fe31e30b7d82ae7778dc2
Author: vnugent <public@vaughnnugent.com>
Date:   Mon Aug 5 18:01:03 2024 -0400

    fix: Find and fix openssl encryption bug

commit a60a3e1ca1d99d655c0cfc96e3952c371e8a8677
Author: vnugent <public@vaughnnugent.com>
Date:   Sun Aug 4 15:27:06 2024 -0400

    cleanup comments + return codes

commit 2aa7f4b6cdb2e0e8990e7177476f4104fd2e2b17
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Jul 27 22:20:53 2024 -0400

    fix codeberg url

commit 1640f79776c6b291b49a39a6128c05888fc4153e
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Jul 27 00:05:07 2024 -0400

    fix: Potential overflow in nip44 padding calculation

commit 07de078a3b5b7b0043d9f81bb5a9e750a3a0c7c1
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Jul 26 23:37:15 2024 -0400

    refactor: Span invasion, checks and fix some evp api

commit 54f520e4bfc0fe23e2719d44b09739aa8709451c
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Jul 23 19:55:13 2024 -0400

    latest changes

commit 12feb33dba2061415d6f39fa59dec16fafcda2a0
Author: vnugent <public@vaughnnugent.com>
Date:   Sun Jul 21 17:51:04 2024 -0400

    Push latest changes, patches, and internal upgrades

commit ffe42b6858f112a00405be4f0605ab1163063749
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Jul 13 22:13:13 2024 -0400

    test: Add decryption test cases and fixes

commit 5dfafbc5a9214587533ec8b1dae2a962118d3650
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Jul 12 22:14:00 2024 -0400

    feat: add decryption functionality to public api

commit 8df8c5aed4ac626171b451b5422c3b207e88000b
Author: vnugent <public@vaughnnugent.com>
Date:   Thu Jul 11 21:39:39 2024 -0400

    feat: Update sidecar utils library

commit 23fe6e8c8596333c2183f0f4389817087442c551
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Jul 5 00:03:48 2024 -0400

    push latest utils and changes

commit dc71f861df8929deee300368b88ef47d45560695
Author: vnugent <public@vaughnnugent.com>
Date:   Mon Jul 1 15:05:34 2024 -0400

    fix: #7 fix confusing inline functions

commit 90166048046d2511f0bb74f8880180e82466d4c0
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Jun 18 21:22:37 2024 -0400

    push pending changes

commit 461dd71069d0c0250752ac1256160605c33a6243
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Jun 11 15:44:28 2024 -0400

    feat!: #4 Close #4. Add public nip04 support to api

commit a74f96251bcc81fb2c94fe75dd6f8043fd35fe0b
Merge: 1c26ef8 51d0aff
Author: vnugent <public@vaughnnugent.com>
Date:   Wed May 29 13:37:00 2024 -0400

    Merge branch 'master' into develop

commit 1c26ef86a04690120f4f752c7c5018a570ec5880
Author: vnugent <public@vaughnnugent.com>
Date:   Wed May 29 13:34:20 2024 -0400

    missed extra argument

commit 88c9095743a12cf8fc1793c607ba3a1e4fa86483
Author: vnugent <public@vaughnnugent.com>
Date:   Wed May 29 13:25:51 2024 -0400

    refactor!: return NC_SUCCESS when validating secret key

commit 718be80a4810b9352de7eb0707da54020aa6b649
Author: vnugent <public@vaughnnugent.com>
Date:   Mon May 27 14:52:41 2024 -0400

    fix: Properly build mbedtls & cmake fixes

commit a8a6efb2319f739e5faae550561dc27d9dd1e88d
Author: vnugent <public@vaughnnugent.com>
Date:   Sun May 26 17:39:40 2024 -0400

    chore: Update libs, reorder files, internalize private headers

commit 72e1b7be4031e2fd4d258fcf434ad049c0029201
Author: vnugent <public@vaughnnugent.com>
Date:   Sun May 26 13:39:08 2024 -0400

    fix: Add c++ extern prototypes in noscrypt.h

commit aeaac8d328b75911541be64d6f09d58fca294a08
Author: vnugent <public@vaughnnugent.com>
Date:   Sun May 26 11:47:17 2024 -0400

    refactor: Dep update, openssl chacha20 added

commit 86b02540cce6015cfe4a2a56499a9a2f45d4e368
Author: vnugent <public@vaughnnugent.com>
Date:   Sat May 18 12:24:17 2024 -0400

    refactor: Remove NCContext structure definition

commit d09d9330415d463ca19be9394b02ce11b3366f7e
Author: vnugent <public@vaughnnugent.com>
Date:   Mon May 13 22:33:50 2024 -0400

    fix: update mbedtls inline issue includes

commit 7838cb4bb15d4f453f92f56ece75e2b03986fe42
Author: vnugent <public@vaughnnugent.com>
Date:   Mon May 13 22:29:16 2024 -0400

    fix: force fPIC for secp256k1 targets

commit d76f7708bc6ae81a638ca708230ac9153ac754e2
Merge: aa8033d a526139
Author: vnugent <public@vaughnnugent.com>
Date:   Sun May 12 00:37:01 2024 -0400

    Merge branch 'master' into develop

commit aa8033d4dbfebeb72b6fd7a0cd218ebde0eb54dd
Author: vnugent <public@vaughnnugent.com>
Date:   Sun May 12 00:34:20 2024 -0400

    Final overview and test before tag

commit 4e3ead2cf1d3068e77f0959dfdc17e20e9102a0f
Merge: 2cee801 872c49d
Author: vnugent <public@vaughnnugent.com>
Date:   Mon May 6 22:08:09 2024 -0400

    Merge branch 'master' into develop

commit 2cee801979bfbcb3b0e53f592ce8c779b57cb679
Author: vnugent <public@vaughnnugent.com>
Date:   Mon May 6 22:02:39 2024 -0400

    Ensure static and dynamic libs get same args

commit f533694023133552d0d42933d779c95a5854343f
Author: vnugent <public@vaughnnugent.com>
Date:   Mon May 6 21:50:29 2024 -0400

    feat: CMake install & fetch-content test & updates

commit 940ff20348b13d0bc30d9e9f4289dd6de20b16ba
Author: vnugent <public@vaughnnugent.com>
Date:   Sun May 5 14:07:28 2024 -0400

    codeberg readonly push

commit b34ed055c0b7d143561ce8798e0a95313b9224bd
Merge: 0a40e20 e737556
Author: vnugent <public@vaughnnugent.com>
Date:   Sat May 4 14:06:45 2024 -0400

    Merge branch 'master' into develop

commit 0a40e209d03e8ff9b6f81cd5969d3e845c633bfc
Author: vnugent <public@vaughnnugent.com>
Date:   Sat May 4 13:55:19 2024 -0400

    ci: Force disable testing for win ci builds

commit 55fae189fffc86f07a3448370f0a746670819712
Author: vnugent <public@vaughnnugent.com>
Date:   Thu May 2 21:54:35 2024 -0400

    feat: Working and tested openssl impl & defaults

commit 6ff8bb11774c51fd341b7699a3938fd894995fbf
Author: vnugent <public@vaughnnugent.com>
Date:   Thu Apr 25 17:45:42 2024 -0400

    refactor: Finish support and testing for mbedtls

commit 7cb7a93de4f6f5e741bc5129e3d928e44f050930
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Apr 23 18:19:31 2024 -0400

    refactor!: MbedTLS on Windows, switch to uint32

commit 30e8dda6cbea86bdee6d5dfe48514385d3b9f81b
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Apr 23 14:48:05 2024 -0400

    refactor: Crypto dep redesign working on Windows

commit d09c6c1bd5da3e2d79351daeba304ca99976a726
Author: vnugent <public@vaughnnugent.com>
Date:   Thu Apr 18 00:28:51 2024 -0400

    refactor!: Pushing what I have to dev

commit 54e06ada7d624ed0d28c6a6db04a149708841bf8
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Apr 13 01:24:00 2024 -0400

    fix: convert constants to hex, inline macro, ParseErrorCode

commit 4215e3100d9a0d23119080d09638fa5b60d0c6d4
Merge: d3328f4 7485aa5
Author: vnugent <public@vaughnnugent.com>
Date:   Wed Apr 3 18:26:30 2024 -0400

    Merge branch 'master' into develop

commit d3328f4152b22b28f24c43dda62464287f1efff5
Author: vnugent <public@vaughnnugent.com>
Date:   Wed Apr 3 18:22:56 2024 -0400

    build: Included dependency and versions in client builds

commit b11bc0bac955fd5c6db65f0da48456bf5e748805
Author: vnugent <public@vaughnnugent.com>
Date:   Wed Apr 3 18:10:08 2024 -0400

    fix: Fix c89 compatabilty comments and struct assignment

commit 9915bd41799a72413e6b400e150aa9f5fa797e25
Merge: 8e3d6ea 5184d7d
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Mar 30 09:57:30 2024 -0400

    Merge branch 'master' into develop

commit 8e3d6ea5e3c83fe42cb904b6ccc4fe2b73f76aae
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Mar 30 09:52:55 2024 -0400

    refactor!: Some api (struct) changes and updated tests

commit e88e8420520204e20802516f01d4488bb0b1d6ea
Merge: 490dfee 21f6c0a
Author: vnugent <public@vaughnnugent.com>
Date:   Sun Mar 3 15:02:34 2024 -0500

    Merge branch 'master' into develop

commit 490dfee4ef22479009627435c6ad728c3cbbab54
Author: vnugent <public@vaughnnugent.com>
Date:   Sun Mar 3 14:59:25 2024 -0500

    test: #3 tests for encryption/description and Macs

commit efa97490b7ed47f4e2f05bee52e2b33e14e439e6
Merge: 1b84e3c 120022a
Author: vnugent <public@vaughnnugent.com>
Date:   Sun Mar 3 14:55:48 2024 -0500

    merge master

commit 1b84e3c7c2e55b1ff9ffdd09b66873e11c131441
Author: vnugent <public@vaughnnugent.com>
Date:   Sat Mar 2 22:57:36 2024 -0500

    fix: #2 constent usage of sizeof() operator on struct types

commit 9de5a214c66adea0ef2d0bac63c59449de202a88
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Mar 1 14:30:36 2024 -0500

    perf: avoid nc_key struct copy, cast and verify instead

commit b917b761120ed684af28d0707673ffadcf14b8fe
Author: vnugent <public@vaughnnugent.com>
Date:   Mon Feb 12 22:06:50 2024 -0500

    fix: found the constant time memcompare function

commit 9f85fff3b9f25da7410569ea94f994b88feb3910
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Feb 9 22:48:35 2024 -0500

    feat: added/update MAC functions to sign or verify nip44 payload

commit aa5113741bb419b02d6ea416bba571fa3d65db46
Author: vnugent <public@vaughnnugent.com>
Date:   Wed Feb 7 01:37:53 2024 -0500

    add missing hmac-key output buffer

commit 55f47d22cc9ce4d1e22b70814d608c7ef3b1bbc9
Author: vnugent <public@vaughnnugent.com>
Date:   Sun Feb 4 21:08:13 2024 -0500

    simple bug fixes, and public api argument validation tests

commit 73c5a713fb164ae8b4ac8a891a8020e08eae0a3b
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Feb 2 23:05:48 2024 -0500

    update api to return secpvalidate return code instead of internal return codes

commit 06c73004e1a39a7ea4ea3a89c22dee0f66adb236
Author: vnugent <public@vaughnnugent.com>
Date:   Fri Feb 2 19:25:17 2024 -0500

    change to lgpl license

commit 6e79fdb3b6b6739fc7797d47e55a7691306cf736
Author: vnugent <public@vaughnnugent.com>
Date:   Wed Jan 31 21:30:49 2024 -0500

    move validation macros, and optionally disable them

commit ac1e58837f1ba687939f78b5c03cadd346c10ddd
Author: vnugent <public@vaughnnugent.com>
Date:   Tue Jan 30 12:25:05 2024 -0500

    couple more tests, renable range checks, set flags for all projects

4 files changed, 270 insertions, 90 deletions

diff --git a/src/providers/bcrypt.c b/src/providers/bcrypt.c
index d1b9aa5..b9c370b 100644
--- a/src/providers/bcrypt.c
+++ b/src/providers/bcrypt.c
@@ -2,7 +2,7 @@
 * Copyright (c) 2024 Vaughn Nugent
 *
 * Package: noscrypt
-* File: impl/bcrypt.c
+* File: providers/bcrypt.c
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
@@ -63,7 +63,7 @@ _IMPLSTB NTSTATUS _bcInitSha256(struct _bcrypt_ctx* ctx, DWORD flags)
 	return result;
 }
 
-_IMPLSTB NTSTATUS _bcCreateHmac(struct _bcrypt_ctx* ctx, const cspan_t* key)
+_IMPLSTB NTSTATUS _bcCreateHmac(struct _bcrypt_ctx* ctx, cspan_t key)
 {
 	/*
 	 * NOTE: 
@@ -79,8 +79,8 @@ _IMPLSTB NTSTATUS _bcCreateHmac(struct _bcrypt_ctx* ctx, const cspan_t* key)
 		&ctx->hHash, 
 		NULL, 
 		0, 
-		(uint8_t*)key->data, 
-		key->size, 
+		(uint8_t*)ncSpanGetOffsetC(key, 0), 
+		ncSpanGetSizeC(key),
 		BCRYPT_HASH_REUSABLE_FLAG	/* Enable reusable for expand function */
 	);
 }
@@ -92,7 +92,7 @@ _IMPLSTB NTSTATUS _bcCreate(struct _bcrypt_ctx* ctx)
 	/* Zero out key span for 0 size and NULL data ptr */
 	SecureZeroMemory(&key, sizeof(cspan_t));
 
-	return _bcCreateHmac(ctx, &key);
+	return _bcCreateHmac(ctx, key);
 }
 
 _IMPLSTB NTSTATUS _bcHashDataRaw(const struct _bcrypt_ctx* ctx, const uint8_t* data, uint32_t len)
@@ -100,9 +100,13 @@ _IMPLSTB NTSTATUS _bcHashDataRaw(const struct _bcrypt_ctx* ctx, const uint8_t* d
 	return BCryptHashData(ctx->hHash, (uint8_t*)data, len, 0);
 }
 
-_IMPLSTB NTSTATUS _bcHashData(const struct _bcrypt_ctx* ctx, const cspan_t* data)
+_IMPLSTB NTSTATUS _bcHashData(const struct _bcrypt_ctx* ctx, cspan_t data)
 {
-	return _bcHashDataRaw(ctx, data->data, data->size);
+	return _bcHashDataRaw(
+		ctx, 
+		ncSpanGetOffsetC(data, 0),
+		ncSpanGetSizeC(data)
+	);
 }
 
 _IMPLSTB NTSTATUS _bcFinishHash(const struct _bcrypt_ctx* ctx, sha256_t digestOut32)
@@ -118,8 +122,8 @@ _IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
 	/* Close the algorithm provider */
 	if (ctx->hAlg) BCryptCloseAlgorithmProvider(ctx->hAlg, 0);
 
-	ctx->hAlg = NULL;
 	ctx->hHash = NULL;
+	ctx->hAlg = NULL;	
 }
 
 #ifndef _IMPL_SECURE_ZERO_MEMSET
@@ -146,7 +150,7 @@ _IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
 	/* Export function fallack */
 	#define _IMPL_CRYPTO_SHA256_DIGEST			_bcrypt_sha256_digest	
 
-	_IMPLSTB cstatus_t _bcrypt_sha256_digest(const cspan_t* data, sha256_t digestOut32)
+	_IMPLSTB cstatus_t _bcrypt_sha256_digest(cspan_t data, sha256_t digestOut32)
 	{
 		cstatus_t result;
 		struct _bcrypt_ctx ctx;
@@ -177,7 +181,7 @@ _IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
 	/* Export function */
 	#define _IMPL_CRYPTO_SHA256_HMAC				_bcrypt_hmac_sha256	
 	
-	_IMPLSTB cstatus_t _bcrypt_hmac_sha256(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+	_IMPLSTB cstatus_t _bcrypt_hmac_sha256(cspan_t key, cspan_t data, sha256_t hmacOut32)
 	{
 		cstatus_t result;
 		struct _bcrypt_ctx ctx;
@@ -213,7 +217,7 @@ _IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
 
 	#define _IMPL_CRYPTO_SHA256_HKDF_EXPAND		_bcrypt_fallback_hkdf_expand
 
-	cstatus_t _bcrypt_hkdf_update(void* ctx, const cspan_t* data)
+	static cstatus_t _bcrypt_hkdf_update(void* ctx, cspan_t data)
 	{
 		DEBUG_ASSERT(ctx != NULL)
 
@@ -221,15 +225,16 @@ _IMPLSTB void _bcDestroyCtx(struct _bcrypt_ctx* ctx)
 		return CSTATUS_OK;
 	}
 
-	cstatus_t _bcrypt_hkdf_finish(void* ctx, sha256_t hmacOut32)
+	static cstatus_t _bcrypt_hkdf_finish(void* ctx, sha256_t hmacOut32)
 	{
-		DEBUG_ASSERT(ctx != NULL)
+		DEBUG_ASSERT(ctx != NULL);
+		DEBUG_ASSERT(hmacOut32 != NULL);
 
 		BC_FAIL(_bcFinishHash((struct _bcrypt_ctx*)ctx, hmacOut32))
 		return CSTATUS_OK;
 	}
 
-	_IMPLSTB cstatus_t _bcrypt_fallback_hkdf_expand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+	_IMPLSTB cstatus_t _bcrypt_fallback_hkdf_expand(cspan_t prk, cspan_t info, span_t okm)
 	{
 		cstatus_t result;
 		struct _bcrypt_ctx ctx;
diff --git a/src/providers/mbedtls.c b/src/providers/mbedtls.c
index df5201f..ead3279 100644
--- a/src/providers/mbedtls.c
+++ b/src/providers/mbedtls.c
@@ -2,7 +2,7 @@
 * Copyright (c) 2024 Vaughn Nugent
 *
 * Package: noscrypt
-* File: mbedtls.c
+* File: providers/mbedtls.c
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
@@ -95,13 +95,13 @@ _IMPLSTB const mbedtls_md_info_t* _mbed_sha256_alg(void)
 	
 	#define _IMPL_CRYPTO_SHA256_DIGEST			_mbed_sha256_digest	
 
-	_IMPLSTB cstatus_t _mbed_sha256_digest(const cspan_t* data, sha256_t digestOut32)
+	_IMPLSTB cstatus_t _mbed_sha256_digest(cspan_t data, sha256_t digestOut32)
 	{
-		_overflow_check(data->size)
+		_overflow_check(data.size)
 
 		return mbedtls_sha256(
-			data->data, 
-			data->size, 
+			data.data, 
+			data.size, 
 			digestOut32, 
 			0				/* Set 0 for sha256 mode */
 		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
@@ -114,19 +114,19 @@ _IMPLSTB const mbedtls_md_info_t* _mbed_sha256_alg(void)
 
 	#define _IMPL_CRYPTO_SHA256_HMAC			_mbed_sha256_hmac
 
-	_IMPLSTB cstatus_t _mbed_sha256_hmac(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+	_IMPLSTB cstatus_t _mbed_sha256_hmac(cspan_t key, cspan_t data, sha256_t hmacOut32)
 	{
-		_overflow_check(data->size)
+		_overflow_check(data.size)
 
 		/* Keys should never be large enough for this to matter, but sanity check. */
-		DEBUG_ASSERT2(key->size < SIZE_MAX, "Expected key size to be less than SIZE_MAX")
+		DEBUG_ASSERT2(key.size < SIZE_MAX, "Expected key size to be less than SIZE_MAX")
 
 		return mbedtls_md_hmac(
 			_mbed_sha256_alg(),
-			key->data, 
-			key->size,
-			data->data, 
-			data->size,
+			key.data, 
+			key.size,
+			data.data, 
+			data.size,
 			hmacOut32
 		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
 	}
@@ -137,21 +137,21 @@ _IMPLSTB const mbedtls_md_info_t* _mbed_sha256_alg(void)
 
 	#define _IMPL_CRYPTO_SHA256_HKDF_EXPAND		_mbed_sha256_hkdf_expand
 
-	_IMPLSTB cstatus_t _mbed_sha256_hkdf_expand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+	_IMPLSTB cstatus_t _mbed_sha256_hkdf_expand(cspan_t prk, cspan_t info, span_t okm)
 	{
 		/* These sizes should never be large enough to overflow on <64bit platforms, but sanity check */
-		DEBUG_ASSERT(okm->size < SIZE_MAX)
-		DEBUG_ASSERT(prk->size < SIZE_MAX)
-		DEBUG_ASSERT(info->size < SIZE_MAX)
+		DEBUG_ASSERT(okm.size < SIZE_MAX)
+		DEBUG_ASSERT(prk.size < SIZE_MAX)
+		DEBUG_ASSERT(info.size < SIZE_MAX)
 
 		return mbedtls_hkdf_expand(
 			_mbed_sha256_alg(),
-			prk->data, 
-			prk->size,
-			info->data, 
-			info->size,
-			okm->data, 
-			okm->size
+			prk.data, 
+			prk.size,
+			info.data, 
+			info.size,
+			okm.data, 
+			okm.size
 		) == 0 ? CSTATUS_OK : CSTATUS_FAIL;
 	}
 
diff --git a/src/providers/monocypher.c b/src/providers/monocypher.c
index 8ffe048..c35f63e 100644
--- a/src/providers/monocypher.c
+++ b/src/providers/monocypher.c
@@ -2,7 +2,7 @@
 * Copyright (c) 2024 Vaughn Nugent
 *
 * Package: noscrypt
-* File: impl/monocypher.c
+* File: providers/monocypher.c
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
diff --git a/src/providers/openssl.c b/src/providers/openssl.c
index 1f31796..c2933fb 100644
--- a/src/providers/openssl.c
+++ b/src/providers/openssl.c
@@ -2,7 +2,7 @@
 * Copyright (c) 2024 Vaughn Nugent
 *
 * Package: noscrypt
-* File: impl/openssl.c
+* File: providers/openssl.c
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
@@ -26,6 +26,10 @@
 
 #define _OSSL_FAIL(x) if(!(x)) return CSTATUS_FAIL;
 
+#define ossl_md_sha256() EVP_MD_fetch(NULL, "SHA2-256", NULL)
+#define ossl_evp_fetch_chacha20() EVP_CIPHER_fetch(NULL, "ChaCha20", NULL)
+#define ossl_mac_fetch_hmac() EVP_MAC_fetch(NULL, "hmac", NULL)
+
 #ifndef _IMPL_SECURE_ZERO_MEMSET
 
 	#define _IMPL_SECURE_ZERO_MEMSET			_ossl_secure_zero_memset
@@ -63,11 +67,20 @@
 
 	#define _IMPL_CRYPTO_SHA256_DIGEST			_ossl_sha256_digest	
 
-	_IMPLSTB cstatus_t _ossl_sha256_digest(const cspan_t* data, sha256_t digestOut32)
+	_IMPLSTB cstatus_t _ossl_sha256_digest(cspan_t data, sha256_t digestOut32)
 	{
-		_overflow_check(data->size)
+		_overflow_check(data.size);
+
+		DEBUG_ASSERT(digestOut32 != NULL);
+		DEBUG_ASSERT(ncSpanIsValidC(data));
 
-		_OSSL_FAIL(SHA256(data->data, data->size, digestOut32))
+		_OSSL_FAIL(
+			SHA256(
+				ncSpanGetOffsetC(data, 0),
+				ncSpanGetSizeC(data),
+				digestOut32
+			)
+		);
 
 		return CSTATUS_OK;
 	}
@@ -81,29 +94,29 @@
 	/* Export function */
 	#define _IMPL_CRYPTO_SHA256_HMAC			_ossl_hmac_sha256	
 	
-	_IMPLSTB cstatus_t _ossl_hmac_sha256(const cspan_t* key, const cspan_t* data, sha256_t hmacOut32)
+	_IMPLSTB cstatus_t _ossl_hmac_sha256(cspan_t key, cspan_t data, sha256_t hmacOut32)
 	{
 		unsigned int hmacLen;
 
-		_overflow_check(key->size)
-		_overflow_check(data->size)
+		_overflow_check(key.size)
+		_overflow_check(data.size)
 
 		hmacLen = sizeof(sha256_t);
 
 		_OSSL_FAIL(
 			HMAC(
-				EVP_sha256(),
-				key->data,
-				key->size,
-				data->data,
-				data->size,
+				ossl_md_sha256(),
+				ncSpanGetOffsetC(key, 0),
+				ncSpanGetSizeC(key),
+				ncSpanGetOffsetC(data, 0),
+				ncSpanGetSizeC(data),
 				hmacOut32,
 				&hmacLen
 			)
-		)
+		);
 		
 		/* digest length should match the actual digest size */
-		DEBUG_ASSERT(hmacLen == sizeof(sha256_t))
+		DEBUG_ASSERT(hmacLen == sizeof(sha256_t));
 
 		return CSTATUS_OK;
 	}
@@ -112,73 +125,144 @@
 
 #ifndef _IMPL_CRYPTO_SHA256_HKDF_EXPAND
 	
-	#include <openssl/hmac.h>
+	#include <openssl/evp.h>
 
 	#define _IMPL_CRYPTO_SHA256_HKDF_EXPAND		_ossl_sha256_hkdf_expand
 
-	cstatus_t _ossl_hkdf_update(void* ctx, const cspan_t* data)
+	struct ossl_hmac_state {
+		EVP_MAC_CTX* libCtx;
+		OSSL_PARAM params[2];
+		cspan_t prk; 
+	};
+
+	static cstatus_t _ossl_hmac_init(const struct ossl_hmac_state* osslCtx)
 	{
-		DEBUG_ASSERT(ctx != NULL)
+		DEBUG_ASSERT(ncSpanIsValidC(osslCtx->prk));
+		DEBUG_ASSERT(osslCtx->params != NULL);
 
-		_overflow_check(data->size)
+		_OSSL_FAIL(
+			EVP_MAC_init(
+				osslCtx->libCtx,
+				ncSpanGetOffsetC(osslCtx->prk, 0),
+				ncSpanGetSizeC(osslCtx->prk),
+				osslCtx->params
+			)
+		);
 
-		_OSSL_FAIL(EVP_DigestUpdate((EVP_MD_CTX*)ctx, data->data, data->size))
-		
 		return CSTATUS_OK;
 	}
 
-	cstatus_t _ossl_hkdf_finish(void* ctx, sha256_t hmacOut32)
+	static cstatus_t _ossl_hkdf_update(void* ctx, cspan_t data)
 	{
-		unsigned int hmacSize;
+		const struct ossl_hmac_state* osslCtx;
 
-		DEBUG_ASSERT(ctx != NULL)
+		DEBUG_ASSERT(ctx != NULL);
+		_overflow_check(data.size);
 
-		hmacSize = sizeof(sha256_t);
+		osslCtx = (const struct ossl_hmac_state*)ctx;
 
-		_OSSL_FAIL(EVP_DigestFinal_ex((EVP_MD_CTX*)ctx, hmacOut32, &hmacSize))
+		DEBUG_ASSERT(osslCtx->libCtx != NULL);
 
-		/* When configured for sha256, should always be the same size in/out */
-		DEBUG_ASSERT(hmacSize == sizeof(sha256_t))
+		_OSSL_FAIL(
+			EVP_MAC_update(
+				osslCtx->libCtx,
+				ncSpanGetOffsetC(data, 0),
+				ncSpanGetSizeC(data)
+			)
+		);
 		
 		return CSTATUS_OK;
 	}
 
-	_IMPLSTB cstatus_t _ossl_sha256_hkdf_expand(const cspan_t* prk, const cspan_t* info, span_t* okm)
+	static cstatus_t _ossl_hkdf_finish(void* ctx, sha256_t hmacOut32)
 	{
-		EVP_MD_CTX* ctx;
+		const struct ossl_hmac_state* osslCtx;
+		size_t hmacSize;
+
+		DEBUG_ASSERT(ctx != NULL);
+		DEBUG_ASSERT(hmacOut32 != NULL);
+
+		osslCtx = (const struct ossl_hmac_state*)ctx;
+		hmacSize = 0;
+
+		DEBUG_ASSERT(osslCtx->libCtx != NULL);
+
+		_OSSL_FAIL(
+			EVP_MAC_final(
+				osslCtx->libCtx,
+				hmacOut32,
+				&hmacSize,
+				sizeof(sha256_t)
+			)
+		);
+
+		/* When configured for sha256, should always be the same size in/out */
+		DEBUG_ASSERT(hmacSize == sizeof(sha256_t));		
+
+		/* 
+		* Context must be re-initalized after finalize
+		* See lifecycle https://docs.openssl.org/3.0/man7/life_cycle-mac/#copyright
+		*/
+
+		return _ossl_hmac_init(osslCtx);
+	}
+	
+
+	_IMPLSTB cstatus_t _ossl_sha256_hkdf_expand(cspan_t prk, cspan_t info, span_t okm)
+	{
+		EVP_MAC* mac;
 		cstatus_t result;
-		struct nc_hkdf_fn_cb_struct handler;
+		struct ossl_hmac_state hkdfState;
+		struct nc_hkdf_fn_cb_struct handler;		
 
 		result = CSTATUS_FAIL;
+
+		handler.update = _ossl_hkdf_update;
+		handler.finish = _ossl_hkdf_finish;
 	
+		_overflow_check(prk.size);
+		_overflow_check(info.size);
+		_overflow_check(okm.size);
+
+		hkdfState.params[0] = OSSL_PARAM_construct_utf8_string("digest", "sha256", 0);
+		hkdfState.params[1] = OSSL_PARAM_construct_end();
+
+		hkdfState.prk = prk;
+
 		/*
-		* NOTE! Hmac reusable flag must be set to allow for multiple
-		* calls to the finish function without losing the context.
+		* Silly openssl stuff. Enable hmac with sha256 using the system default
+		* security provider. The one-shot flag must also be disabled (0) because
+		* we need to call update multiple times.
 		*/
 
-		if ((ctx = EVP_MD_CTX_create()) == NULL)
+		mac = ossl_mac_fetch_hmac();
+
+		if (mac == NULL)
 		{
-			return CSTATUS_FAIL;
+			goto Cleanup;
 		}
 
-		if (!EVP_DigestInit_ex2(ctx, EVP_sha256(), NULL))
+		hkdfState.libCtx = EVP_MAC_CTX_new(mac);
+
+		if (hkdfState.libCtx == NULL)
 		{
 			goto Cleanup;
 		}
 
-		if (!EVP_DigestUpdate(ctx, prk->data, prk->size)) 
+		if (_ossl_hmac_init(&hkdfState) != CSTATUS_OK)
 		{
 			goto Cleanup;
 		}
-		
-		handler.update = _ossl_hkdf_update;
-		handler.finish = _ossl_hkdf_finish;
 
-		result = hkdfExpandProcess(&handler, ctx, info, okm);
+		DEBUG_ASSERT(EVP_MAC_CTX_get_mac_size(hkdfState.libCtx) == sizeof(sha256_t));
 
-	Cleanup:
+		/* Pass the library  */
+		result = hkdfExpandProcess(&handler, &hkdfState, info, okm);
 
-		EVP_MD_CTX_destroy(ctx);
+	Cleanup:
+		
+		if (hkdfState.libCtx) EVP_MAC_CTX_free(hkdfState.libCtx);
+		if (mac) EVP_MAC_free(mac);
 
 		return result;
 	}
@@ -191,39 +275,130 @@
 
 	#define _IMPL_CHACHA20_CRYPT _ossl_chacha20_crypt
 
-	_IMPLSTB cstatus_t _ossl_chacha20_crypt(
-		const uint8_t* key,
-		const uint8_t* nonce,
-		const uint8_t* input,
-		uint8_t* output,
-		uint32_t dataLen
+	_IMPLSTB cstatus_t _ossl_cipher_core(
+		const EVP_CIPHER* cipher,
+		cspan_t key,
+		cspan_t iv,
+		cspan_t input,
+		span_t output
 	)
 	{
 		cstatus_t result;
 		EVP_CIPHER_CTX* ctx;
+		int tempLen, osslResult;
+
+		DEBUG_ASSERT2(ncSpanGetSize(output) <= ncSpanGetSizeC(input), "Output buffer must be equal or larger than the input buffer");
+		DEBUG_ASSERT(cipher != NULL);
+
+		DEBUG_ASSERT((uint32_t)EVP_CIPHER_get_key_length(cipher) == ncSpanGetSizeC(key));
+		DEBUG_ASSERT((uint32_t)EVP_CIPHER_iv_length(cipher) == ncSpanGetSizeC(iv));
 
 		result = CSTATUS_FAIL;
 
-		if ((ctx = EVP_CIPHER_CTX_new()) == NULL)
+		ctx = EVP_CIPHER_CTX_new();
+
+		if (ctx == NULL)
 		{
-			return CSTATUS_FAIL;
+			goto Cleanup;
 		}
 
-		if (!EVP_EncryptInit_ex(ctx, EVP_chacha20(), NULL, key, nonce))
+		osslResult = EVP_EncryptInit_ex2(
+			ctx, 
+			cipher, 
+			ncSpanGetOffsetC(key, 0),
+			ncSpanGetOffsetC(iv, 0),
+			NULL
+		);
+
+		if (!osslResult)
 		{
 			goto Cleanup;
 		}
 
-		if (!EVP_EncryptUpdate(ctx, output, (int*)&dataLen, input, dataLen))
+		osslResult = EVP_EncryptUpdate(
+			ctx,
+			ncSpanGetOffset(output, 0),
+			&tempLen,
+			ncSpanGetOffsetC(input, 0),
+			ncSpanGetSizeC(input)
+		);
+
+		if (!osslResult)
 		{
 			goto Cleanup;
 		}
 
+		/*
+		* We can't get a pointer outside the range of the 
+		* output buffer
+		*/
+		if (((uint32_t)tempLen) < ncSpanGetSize(output))
+		{
+			if (!EVP_EncryptFinal_ex(ctx, ncSpanGetOffset(output, tempLen), &tempLen))
+			{
+				goto Cleanup;
+			}
+		}
+
 		result = CSTATUS_OK;
 
 	Cleanup:
 
-		EVP_CIPHER_CTX_free(ctx);
+		if (ctx) EVP_CIPHER_CTX_free(ctx);
+
+		return result;
+	}
+
+	_IMPLSTB cstatus_t _ossl_chacha20_crypt(
+		const uint8_t* key,
+		const uint8_t* nonce,
+		const uint8_t* input,
+		uint8_t* output,
+		uint32_t dataLen
+	)
+	{
+		cstatus_t result;
+		EVP_CIPHER* cipher;
+		uint8_t chaChaIv[CHACHA_NONCE_SIZE + 4];
+		cspan_t keySpan, nonceSpan, inputSpan;
+		span_t outputSpan;
+
+		result = CSTATUS_FAIL;
+
+		/*
+		* RFC 7539 ChaCha20 requires a 16 byte initialization vector. A 
+		* counter value is preprended to the nonce to make up the 16 byte 
+		* size.
+		*
+		* The counter is always set to 0 for the nonce.
+		*/
+
+		ncCryptoSecureZero(chaChaIv, sizeof(chaChaIv));
+		MEMMOV(chaChaIv + 4, nonce, CHACHA_NONCE_SIZE);
+
+		ncSpanInitC(&keySpan, key, CHACHA_KEY_SIZE);
+		ncSpanInitC(&nonceSpan, chaChaIv, sizeof(chaChaIv));
+		ncSpanInitC(&inputSpan, input, dataLen);
+		ncSpanInit(&outputSpan, output, dataLen);
+
+		cipher = ossl_evp_fetch_chacha20();
+
+		if (cipher == NULL)
+		{
+			goto Cleanup;
+		}
+
+		result = _ossl_cipher_core(
+			cipher, 
+			keySpan, 
+			nonceSpan, 
+			inputSpan, 
+			outputSpan
+		);
+
+	Cleanup:
+		
+		if (cipher) EVP_CIPHER_free(cipher);
 
 		return result;
 	}