factoring out AES-specific stuff

4 files changed, 171 insertions, 219 deletions

diff --git a/src/data.c b/src/aes.c
index ef2d7f3..98cc9cd 100644
--- a/src/data.c
+++ b/src/aes.c
@@ -8,13 +8,14 @@
 
 #include <aesni/all.h>
 
-#include <intrin.h>
-
 #include <assert.h>
 #include <stdio.h>
 #include <string.h>
 
-AesNI_StatusCode aesni_format_block128(AesNI_BlockString128* str, const AesNI_Block128* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes_format_block(
+    AesNI_Aes_BlockString* str,
+    const AesNI_Aes_Block* block,
+    AesNI_ErrorDetails* err_details)
 {
     assert(str);
     assert(block);
@@ -33,10 +34,13 @@ AesNI_StatusCode aesni_format_block128(AesNI_BlockString128* str, const AesNI_Bl
         sprintf(cursor, "%02x", bytes[i]);
 
     *cursor = '\0';
-    return aesni_initialize_error_details(err_details);
+    return AESNI_SUCCESS;
 }
 
-AesNI_StatusCode aesni_format_block192(AesNI_BlockString192* str, const AesNI_Block192* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes_format_block_as_matrix(
+    AesNI_Aes_BlockMatrixString* str,
+    const AesNI_Aes_Block* block,
+    AesNI_ErrorDetails* err_details)
 {
     assert(str);
     assert(block);
@@ -48,272 +52,220 @@ AesNI_StatusCode aesni_format_block192(AesNI_BlockString192* str, const AesNI_Bl
 
     char* cursor = str->str;
 
-    {
-        __declspec(align(16)) unsigned char bytes[16];
-        aesni_store_block128_aligned(bytes, block->lo);
-
-        for (int i = 0; i < 16; ++i, cursor += 2)
-            sprintf(cursor, "%02x", bytes[i]);
-    }
+    __declspec(align(16)) unsigned char bytes[4][4];
+    aesni_store_block128_aligned(bytes, *block);
 
+    for (int i = 0; i < 4; ++i, cursor += 3)
     {
-        __declspec(align(16)) unsigned char bytes[16];
-        aesni_store_block128_aligned(bytes, block->hi);
-
-        for (int i = 0; i < 8; ++i, cursor += 2)
-            sprintf(cursor, "%02x", bytes[i]);
+        for (int j = 0; j < 3; ++j, cursor += 3)
+            sprintf(cursor, "%02x ", bytes[j][i]);
+        sprintf(cursor, "%02x\n", bytes[3][i]);
     }
 
     *cursor = '\0';
-    return aesni_initialize_error_details(err_details);
+    return AESNI_SUCCESS;
 }
 
-AesNI_StatusCode aesni_format_block256(AesNI_BlockString256* str, const AesNI_Block256* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes_print_block(
+    const AesNI_Aes_Block* block,
+    AesNI_ErrorDetails* err_details)
 {
-    assert(str);
     assert(block);
 
-    if (str == NULL)
-        return aesni_make_null_argument_error(err_details, "str");
     if (block == NULL)
         return aesni_make_null_argument_error(err_details, "block");
 
-    char* cursor = str->str;
+    AesNI_StatusCode ec = AESNI_SUCCESS;
+    AesNI_Aes_BlockString str;
 
-    {
-        __declspec(align(16)) unsigned char bytes[16];
-        aesni_store_block128_aligned(bytes, block->lo);
-
-        for (int i = 0; i < 16; ++i, cursor += 2)
-            sprintf(cursor, "%02x", bytes[i]);
-    }
-
-    {
-        __declspec(align(16)) unsigned char bytes[16];
-        aesni_store_block128_aligned(bytes, block->hi);
-
-        for (int i = 0; i < 16; ++i, cursor += 2)
-            sprintf(cursor, "%02x", bytes[i]);
-    }
+    if (aesni_is_error(ec = aesni_aes_format_block(&str, block, err_details)))
+        return ec;
 
-    *cursor = '\0';
-    return aesni_initialize_error_details(err_details);
+    printf("%s\n", str.str);
+    return ec;
 }
 
-AesNI_StatusCode aesni_format_block128_as_matrix(AesNI_BlockMatrixString128* str, const AesNI_Block128* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes_print_block_as_matrix(
+    const AesNI_Aes_Block* block,
+    AesNI_ErrorDetails* err_details)
 {
-    assert(str);
     assert(block);
 
-    if (str == NULL)
-        return aesni_make_null_argument_error(err_details, "str");
     if (block == NULL)
         return aesni_make_null_argument_error(err_details, "block");
 
-    char* cursor = str->str;
+    AesNI_StatusCode ec = AESNI_SUCCESS;
+    AesNI_Aes_BlockMatrixString str;
 
-    __declspec(align(16)) unsigned char bytes[4][4];
-    aesni_store_block128_aligned(bytes, *block);
+    if (aesni_is_error(ec = aesni_aes_format_block_as_matrix(&str, block, err_details)))
+        return ec;
 
-    for (int i = 0; i < 4; ++i, cursor += 3)
+    printf("%s", str.str);
+    return ec;
+}
+
+AesNI_StatusCode aesni_aes_parse_block(
+    AesNI_Aes_Block* dest,
+    const char* src,
+    AesNI_ErrorDetails* err_details)
+{
+    assert(dest);
+    assert(src);
+
+    if (dest == NULL)
+        return aesni_make_null_argument_error(err_details, "dest");
+    if (src == NULL)
+        return aesni_make_null_argument_error(err_details, "src");
+
+    __declspec(align(16)) unsigned char bytes[16];
+
+    for (int i = 0; i < 16; ++i)
     {
-        for (int j = 0; j < 3; ++j, cursor += 3)
-            sprintf(cursor, "%02x ", bytes[j][i]);
-        sprintf(cursor, "%02x\n", bytes[3][i]);
+        int n;
+        unsigned int byte;
+        if (sscanf(src, "%2x%n", &byte, &n) != 1)
+            return aesni_make_parse_error(err_details, src);
+        bytes[i] = (unsigned char) byte;
+        src += n;
     }
 
-    *cursor = '\0';
-    return aesni_initialize_error_details(err_details);
+    *dest = aesni_load_block128_aligned(bytes);
+    return AESNI_SUCCESS;
+}
+
+AesNI_StatusCode aesni_aes128_format_key(
+    AesNI_Aes128_KeyString* str,
+    const AesNI_Aes128_Key* key,
+    AesNI_ErrorDetails* err_details)
+{
+    return aesni_aes_format_block(str, &key->key, err_details);
 }
 
-AesNI_StatusCode aesni_format_block192_as_matrix(AesNI_BlockMatrixString192* str, const AesNI_Block192* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes192_format_key(
+    AesNI_Aes192_KeyString* str,
+    const AesNI_Aes192_Key* key,
+    AesNI_ErrorDetails* err_details)
 {
     assert(str);
-    assert(block);
+    assert(key);
 
     if (str == NULL)
         return aesni_make_null_argument_error(err_details, "str");
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
+    if (key == NULL)
+        return aesni_make_null_argument_error(err_details, "key");
 
     char* cursor = str->str;
 
-    __declspec(align(16)) unsigned char bytes[8][4];
-    aesni_store_block128_aligned(bytes, block->lo);
-    aesni_store_block128_aligned(bytes + 4, block->hi);
+    {
+        __declspec(align(16)) unsigned char bytes[16];
+        aesni_store_block128_aligned(bytes, key->lo);
+
+        for (int i = 0; i < 16; ++i, cursor += 2)
+            sprintf(cursor, "%02x", bytes[i]);
+    }
 
-    for (int i = 0; i < 4; ++i, cursor += 3)
     {
-        for (int j = 0; j < 5; ++j, cursor += 3)
-            sprintf(cursor, "%02x ", bytes[j][i]);
-        sprintf(cursor, "%02x\n", bytes[5][i]);
+        __declspec(align(16)) unsigned char bytes[16];
+        aesni_store_block128_aligned(bytes, key->hi);
+
+        for (int i = 0; i < 8; ++i, cursor += 2)
+            sprintf(cursor, "%02x", bytes[i]);
     }
 
     *cursor = '\0';
-    return aesni_initialize_error_details(err_details);
+    return AESNI_SUCCESS;
 }
 
-AesNI_StatusCode aesni_format_block256_as_matrix(AesNI_BlockMatrixString256* str, const AesNI_Block256* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes256_format_key(
+    AesNI_Aes256_KeyString* str,
+    const AesNI_Aes256_Key* key,
+    AesNI_ErrorDetails* err_details)
 {
     assert(str);
-    assert(block);
+    assert(key);
 
     if (str == NULL)
         return aesni_make_null_argument_error(err_details, "str");
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
+    if (key == NULL)
+        return aesni_make_null_argument_error(err_details, "key");
 
     char* cursor = str->str;
 
-    __declspec(align(16)) unsigned char bytes[8][4];
-    aesni_store_block128_aligned(bytes, block->lo);
-    aesni_store_block128_aligned(bytes + 4, block->hi);
+    {
+        __declspec(align(16)) unsigned char bytes[16];
+        aesni_store_block128_aligned(bytes, key->lo);
+
+        for (int i = 0; i < 16; ++i, cursor += 2)
+            sprintf(cursor, "%02x", bytes[i]);
+    }
 
-    for (int i = 0; i < 4; ++i, cursor += 3)
     {
-        for (int j = 0; j < 7; ++j, cursor += 3)
-            sprintf(cursor, "%02x ", bytes[j][i]);
-        sprintf(cursor, "%02x\n", bytes[7][i]);
+        __declspec(align(16)) unsigned char bytes[16];
+        aesni_store_block128_aligned(bytes, key->hi);
+
+        for (int i = 0; i < 16; ++i, cursor += 2)
+            sprintf(cursor, "%02x", bytes[i]);
     }
 
     *cursor = '\0';
-    return aesni_initialize_error_details(err_details);
+    return AESNI_SUCCESS;
 }
 
-AesNI_StatusCode aesni_print_block128(const AesNI_Block128* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes128_print_key(
+    const AesNI_Aes128_Key* key,
+    AesNI_ErrorDetails* err_details)
 {
-    assert(block);
-
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
-
-    AesNI_StatusCode ec = aesni_initialize_error_details(err_details);
-    AesNI_BlockString128 str;
-
-    if (aesni_is_error(ec = aesni_format_block128(&str, block, err_details)))
-        return ec;
-
-    printf("%s\n", str.str);
-    return ec;
+    return aesni_aes_print_block(&key->key, err_details);
 }
 
-AesNI_StatusCode aesni_print_block192(const AesNI_Block192* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes192_print_key(
+    const AesNI_Aes192_Key* key,
+    AesNI_ErrorDetails* err_details)
 {
-    assert(block);
+    assert(key);
 
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
+    if (key == NULL)
+        return aesni_make_null_argument_error(err_details, "key");
 
-    AesNI_StatusCode ec = aesni_initialize_error_details(err_details);
-    AesNI_BlockString192 str;
+    AesNI_StatusCode ec = AESNI_SUCCESS;
+    AesNI_Aes192_KeyString str;
 
-    if (aesni_is_error(ec = aesni_format_block192(&str, block, err_details)))
+    if (aesni_is_error(ec = aesni_aes192_format_key(&str, key, err_details)))
         return ec;
 
     printf("%s\n", str.str);
     return ec;
 }
 
-AesNI_StatusCode aesni_print_block256(const AesNI_Block256* block, AesNI_ErrorDetails* err_details)
+AesNI_StatusCode aesni_aes256_print_key(
+    const AesNI_Aes256_Key* key,
+    AesNI_ErrorDetails* err_details)
 {
-    assert(block);
+    assert(key);
 
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
+    if (key == NULL)
+        return aesni_make_null_argument_error(err_details, "key");
 
-    AesNI_StatusCode ec = aesni_initialize_error_details(err_details);
-    AesNI_BlockString256 str;
+    AesNI_StatusCode ec = AESNI_SUCCESS;
+    AesNI_Aes256_KeyString str;
 
-    if (aesni_is_error(ec = aesni_format_block256(&str, block, err_details)))
+    if (aesni_is_error(ec = aesni_aes256_format_key(&str, key, err_details)))
         return ec;
 
     printf("%s\n", str.str);
     return ec;
 }
 
-AesNI_StatusCode aesni_print_block128_as_matrix(const AesNI_Block128* block, AesNI_ErrorDetails* err_details)
-{
-    assert(block);
-
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
-
-    AesNI_StatusCode ec = aesni_initialize_error_details(err_details);
-    AesNI_BlockMatrixString128 str;
-
-    if (aesni_is_error(ec = aesni_format_block128_as_matrix(&str, block, err_details)))
-        return ec;
-
-    printf("%s", str.str);
-    return ec;
-}
-
-AesNI_StatusCode aesni_print_block192_as_matrix(const AesNI_Block192* block, AesNI_ErrorDetails* err_details)
-{
-    assert(block);
-
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
-
-    AesNI_StatusCode ec = aesni_initialize_error_details(err_details);
-    AesNI_BlockMatrixString192 str;
-
-    if (aesni_is_error(ec = aesni_format_block192_as_matrix(&str, block, err_details)))
-        return ec;
-
-    printf("%s", str.str);
-    return ec;
-}
-
-AesNI_StatusCode aesni_print_block256_as_matrix(const AesNI_Block256* block, AesNI_ErrorDetails* err_details)
-{
-    assert(block);
-
-    if (block == NULL)
-        return aesni_make_null_argument_error(err_details, "block");
-
-    AesNI_StatusCode ec = aesni_initialize_error_details(err_details);
-    AesNI_BlockMatrixString256 str;
-
-    if (aesni_is_error(ec = aesni_format_block256_as_matrix(&str, block, err_details)))
-        return ec;
-
-    printf("%s", str.str);
-    return ec;
-}
-
-AesNI_StatusCode aesni_parse_block128(
-    AesNI_Block128* dest,
+AesNI_StatusCode aesni_aes128_parse_key(
+    AesNI_Aes128_Key* dest,
     const char* src,
     AesNI_ErrorDetails* err_details)
 {
-    assert(dest);
-    assert(src);
-
-    if (dest == NULL)
-        return aesni_make_null_argument_error(err_details, "dest");
-    if (src == NULL)
-        return aesni_make_null_argument_error(err_details, "src");
-
-    __declspec(align(16)) unsigned char bytes[16];
-
-    for (int i = 0; i < 16; ++i)
-    {
-        int n;
-        unsigned int byte;
-        if (sscanf(src, "%2x%n", &byte, &n) != 1)
-            return aesni_make_parse_error(err_details, src);
-        bytes[i] = (unsigned char) byte;
-        src += n;
-    }
-
-    *dest = aesni_load_block128_aligned(bytes);
-
-    return aesni_initialize_error_details(err_details);
+    return aesni_aes_parse_block(&dest->key, src, err_details);
 }
 
-AesNI_StatusCode aesni_parse_block192(
-    AesNI_Block192* dest,
+AesNI_StatusCode aesni_aes192_parse_key(
+    AesNI_Aes192_Key* dest,
     const char* src,
     AesNI_ErrorDetails* err_details)
 {
@@ -358,11 +310,11 @@ AesNI_StatusCode aesni_parse_block192(
         dest->hi = aesni_load_block128_aligned(bytes);
     }
 
-    return aesni_initialize_error_details(err_details);
+    return AESNI_SUCCESS;
 }
 
-AesNI_StatusCode aesni_parse_block256(
-    AesNI_Block256* dest,
+AesNI_StatusCode aesni_aes256_parse_key(
+    AesNI_Aes256_Key* dest,
     const char* src,
     AesNI_ErrorDetails* err_details)
 {
@@ -406,5 +358,5 @@ AesNI_StatusCode aesni_parse_block256(
         dest->hi = aesni_load_block128_aligned(bytes);
     }
 
-    return aesni_initialize_error_details(err_details);
+    return AESNI_SUCCESS;
 }
diff --git a/src/c/aes128.c b/src/c/aes128.c
index 8f2da44..b2e37ba 100644
--- a/src/c/aes128.c
+++ b/src/c/aes128.c
@@ -11,8 +11,8 @@
 #include <emmintrin.h>
 #include <wmmintrin.h>
 
-AesNI_Block128 __fastcall aesni_aes128_encrypt_block_(
-    AesNI_Block128 plaintext,
+AesNI_Aes_Block __fastcall aesni_aes128_encrypt_block_(
+    AesNI_Aes_Block plaintext,
     const AesNI_Aes128_RoundKeys* encryption_keys)
 {
     plaintext = _mm_xor_si128(plaintext, encryption_keys->keys[0]);
@@ -28,8 +28,8 @@ AesNI_Block128 __fastcall aesni_aes128_encrypt_block_(
     return _mm_aesenclast_si128(plaintext, encryption_keys->keys[10]);
 }
 
-AesNI_Block128 __fastcall aesni_aes128_decrypt_block_(
-    AesNI_Block128 ciphertext,
+AesNI_Aes_Block __fastcall aesni_aes128_decrypt_block_(
+    AesNI_Aes_Block ciphertext,
     const AesNI_Aes128_RoundKeys* decryption_keys)
 {
     ciphertext = _mm_xor_si128(ciphertext, decryption_keys->keys[0]);
@@ -45,11 +45,11 @@ AesNI_Block128 __fastcall aesni_aes128_decrypt_block_(
     return _mm_aesdeclast_si128(ciphertext, decryption_keys->keys[10]);
 }
 
-static AesNI_Block128 __fastcall aesni_aes128_expand_key_assist(
-    AesNI_Block128 prev,
-    AesNI_Block128 hwgen)
+static AesNI_Aes_Block __fastcall aesni_aes128_expand_key_assist(
+    AesNI_Aes_Block prev,
+    AesNI_Aes_Block hwgen)
 {
-    AesNI_Block128 tmp = prev;
+    AesNI_Aes_Block tmp = prev;
 
     tmp = _mm_slli_si128(tmp, 4);
     prev = _mm_xor_si128(prev, tmp);
@@ -65,7 +65,7 @@ static AesNI_Block128 __fastcall aesni_aes128_expand_key_assist(
 }
 
 void __fastcall aesni_aes128_expand_key_(
-    AesNI_Block128 key,
+    AesNI_Aes_Block key,
     AesNI_Aes128_RoundKeys* encryption_keys)
 {
     AesNI_Block128 prev = encryption_keys->keys[0] = key;
diff --git a/src/c/aes192.c b/src/c/aes192.c
index 6e97637..702ee5e 100644
--- a/src/c/aes192.c
+++ b/src/c/aes192.c
@@ -11,8 +11,8 @@
 #include <emmintrin.h>
 #include <wmmintrin.h>
 
-AesNI_Block128 __fastcall aesni_aes192_encrypt_block_(
-    AesNI_Block128 plaintext,
+AesNI_Aes_Block __fastcall aesni_aes192_encrypt_block_(
+    AesNI_Aes_Block plaintext,
     const AesNI_Aes192_RoundKeys* encryption_keys)
 {
     plaintext = _mm_xor_si128(plaintext, encryption_keys->keys[0]);
@@ -30,8 +30,8 @@ AesNI_Block128 __fastcall aesni_aes192_encrypt_block_(
     return _mm_aesenclast_si128(plaintext, encryption_keys->keys[12]);
 }
 
-AesNI_Block128 __fastcall aesni_aes192_decrypt_block_(
-    AesNI_Block128 ciphertext,
+AesNI_Aes_Block __fastcall aesni_aes192_decrypt_block_(
+    AesNI_Aes_Block ciphertext,
     const AesNI_Aes192_RoundKeys* decryption_keys)
 {
     ciphertext = _mm_xor_si128(ciphertext, decryption_keys->keys[0]);
@@ -50,11 +50,11 @@ AesNI_Block128 __fastcall aesni_aes192_decrypt_block_(
 }
 
 static void __fastcall aesni_aes192_expand_key_assist(
-    AesNI_Block128* prev_lo,
-    AesNI_Block128* prev_hi,
-    AesNI_Block128 hwgen)
+    AesNI_Aes_Block* prev_lo,
+    AesNI_Aes_Block* prev_hi,
+    AesNI_Aes_Block hwgen)
 {
-    AesNI_Block128 tmp = *prev_lo;
+    AesNI_Aes_Block tmp = *prev_lo;
 
     tmp = _mm_slli_si128(tmp, 4);
     *prev_lo = _mm_xor_si128(*prev_lo, tmp);
@@ -75,8 +75,8 @@ static void __fastcall aesni_aes192_expand_key_assist(
 }
 
 void __fastcall aesni_aes192_expand_key_(
-    AesNI_Block128 key_lo,
-    AesNI_Block128 key_hi,
+    AesNI_Aes_Block key_lo,
+    AesNI_Aes_Block key_hi,
     AesNI_Aes192_RoundKeys* encryption_keys)
 {
     encryption_keys->keys[0] = key_lo;
diff --git a/src/c/aes256.c b/src/c/aes256.c
index 820010d..243ec03 100644
--- a/src/c/aes256.c
+++ b/src/c/aes256.c
@@ -11,8 +11,8 @@
 #include <emmintrin.h>
 #include <wmmintrin.h>
 
-AesNI_Block128 __fastcall aesni_aes256_encrypt_block_(
-    AesNI_Block128 plaintext,
+AesNI_Aes_Block __fastcall aesni_aes256_encrypt_block_(
+    AesNI_Aes_Block plaintext,
     const AesNI_Aes256_RoundKeys* encryption_keys)
 {
     plaintext = _mm_xor_si128(plaintext, encryption_keys->keys[0]);
@@ -32,8 +32,8 @@ AesNI_Block128 __fastcall aesni_aes256_encrypt_block_(
     return _mm_aesenclast_si128(plaintext, encryption_keys->keys[14]);
 }
 
-AesNI_Block128 __fastcall aesni_aes256_decrypt_block_(
-    AesNI_Block128 ciphertext,
+AesNI_Aes_Block __fastcall aesni_aes256_decrypt_block_(
+    AesNI_Aes_Block ciphertext,
     const AesNI_Aes256_RoundKeys* decryption_keys)
 {
     ciphertext = _mm_xor_si128(ciphertext, decryption_keys->keys[0]);
@@ -53,12 +53,12 @@ AesNI_Block128 __fastcall aesni_aes256_decrypt_block_(
     return _mm_aesdeclast_si128(ciphertext, decryption_keys->keys[14]);
 }
 
-static AesNI_Block128 __fastcall aesni_aes256_expand_key_assist(
-    AesNI_Block128* prev_lo,
-    AesNI_Block128* prev_hi,
-    AesNI_Block128 hwgen)
+static AesNI_Aes_Block __fastcall aesni_aes256_expand_key_assist(
+    AesNI_Aes_Block* prev_lo,
+    AesNI_Aes_Block* prev_hi,
+    AesNI_Aes_Block hwgen)
 {
-    AesNI_Block128 tmp = *prev_lo;
+    AesNI_Aes_Block tmp = *prev_lo;
 
     tmp = _mm_slli_si128(tmp, 4);
     *prev_lo = _mm_xor_si128(*prev_lo, tmp);
@@ -77,12 +77,12 @@ static AesNI_Block128 __fastcall aesni_aes256_expand_key_assist(
 }
 
 void __fastcall aesni_aes256_expand_key_(
-    AesNI_Block128 key_lo,
-    AesNI_Block128 key_hi,
+    AesNI_Aes_Block key_lo,
+    AesNI_Aes_Block key_hi,
     AesNI_Aes256_RoundKeys* encryption_keys)
 {
-    AesNI_Block128 prev_lo, prev_hi;
-    AesNI_Block128 hwgen;
+    AesNI_Aes_Block prev_lo, prev_hi;
+    AesNI_Aes_Block hwgen;
 
     prev_lo = encryption_keys->keys[0] = key_lo;
     prev_hi = encryption_keys->keys[1] = key_hi;