Added support for aes 128 encryption

Author: DavyLandman

aeslib.c

@@ -18,10 +18,64 @@
 #include "aeslib.h"
 #include <stdint.h>
 #include "aes.h"
+#include "blockcipher_descriptor.h"
 #include "bcal_aes128.h"
 #include "bcal-cbc.h"
+#include <avr/pgmspace.h>
 
+// encrypt multiple blocks of 128bit data, data_len but be mod 16
+// key and iv are assumed to be both 128bit thus 16 uint8_t's
+void aes128_cbc_enc(uint8_t* key, uint8_t* iv, void* data, uint16_t data_len){
+	if (data_len % 16 != 0) {
+		return;
+	}
+	bcal_cbc_ctx_t ctx;
+	uint8_t r;
+	r = bcal_cbc_init(&aes128_desc, key, 128, &ctx);
+	if (r) {
+		return;
+	}
+	bcal_cbc_encMsg(iv, data, data_len / 16, &ctx);
+	bcal_cbc_free(&ctx);
+}
+
+// encrypt single 128bit block. data is assumed to be 16 uint8_t's
+// key and iv are assumed to be both 128bit thus 16 uint8_t's
+void aes128_enc_single(uint8_t* key, void* data){
+	aes128_ctx_t ctx;
+	aes128_init(key, &ctx);
+	aes128_enc(data, &ctx);
+}
 
-void aes128_encrypt(uint8_t* key, uint8_t* iv, uint8_t* data, uint32_t data_len) {
+// prepare an encrypted to use for encrypting multiple blocks lateron.
+// key and iv are assumed to be both 128bit thus 16 uint8_t's
+aes_context aes128_cbc_enc_start(uint8_t* key, void* iv){
+	bcal_cbc_ctx_t* ctx = (bcal_cbc_ctx_t*)malloc(sizeof(bcal_cbc_ctx_t));
+	uint8_t r = bcal_cbc_init(&aes128_desc, key, 128, ctx);
+	if (r) {
+		free(ctx);
+		return NULL;
+	}
+	bcal_cbc_loadIV(iv, ctx);
+	return (aes_context)ctx;
+}
+
+// encrypt one or more blocks of 128bit data
+// data_len should be mod 16
+void aes128_cbc_enc_continue(aes_context ctx, void* data, uint16_t data_len){
+	if (data_len % 16 != 0) {
+		return;
+	}
+	bcal_cbc_ctx_t* _ctx = (bcal_cbc_ctx_t*)ctx;
+	uint16_t msg_blocks = data_len / 16;
+	while(msg_blocks--){
+		bcal_cbc_encNext(data, _ctx);
+		data = (uint8_t*)data + _ctx->blocksize_B;
+	}
+}
 
+// cleanup encryption context
+void aes128_cbc_enc_finish(aes_context ctx){
+	bcal_cbc_free((bcal_cbc_ctx_t*)ctx);
+	free(ctx);
 }

aeslib.h

@@ -18,6 +18,25 @@
 #ifndef AESLIB_H
 #define AESLIB_H
 #include <stdint.h>
-void aes128_encrypt(uint8_t* key, uint8_t* iv, uint8_t* data, uint32_t data_len);
+// encrypt multiple blocks of 128bit data, data_len but be mod 16
+// key and iv are assumed to be both 128bit thus 16 uint8_t's
+void aes128_cbc_enc(uint8_t* key, uint8_t* iv, void* data, uint16_t data_len);
+
+// encrypt single 128bit block. data is assumed to be 16 uint8_t's
+// key and iv are assumed to be both 128bit thus 16 uint8_t's
+void aes128_enc_single(uint8_t* key, void* data);
+
+typedef void* aes_context;
+
+// prepare an encrypted to use for encrypting multiple blocks lateron.
+// key and iv are assumed to be both 128bit thus 16 uint8_t's
+aes_context aes128_cbc_enc_start(uint8_t* key, void* iv);
+
+// encrypt one or more blocks of 128bit data
+// data_len should be mod 16
+void aes128_cbc_enc_continue(aes_context ctx, void* data, uint16_t data_len);
+
+// cleanup encryption context
+void aes128_cbc_enc_finish(aes_context ctx);
 
 #endif