diff --git a/common/nistkatrng.c b/common/nistkatrng.c
index 746b0dc3..368d0db3 100644
--- a/common/nistkatrng.c
+++ b/common/nistkatrng.c
@@ -19,7 +19,7 @@ typedef struct {
 } AES256_CTR_DRBG_struct;
 
 static AES256_CTR_DRBG_struct DRBG_ctx;
-static void AES256_CTR_DRBG_Update(uint8_t *provided_data, uint8_t *Key, uint8_t *V);
+static void AES256_CTR_DRBG_Update(const uint8_t *provided_data, uint8_t *Key, uint8_t *V);
 
 // Use whatever AES implementation you have. This uses AES from openSSL library
 //    key - 256-bit AES key
@@ -31,23 +31,24 @@ static void AES256_ECB(uint8_t *key, uint8_t *ctr, uint8_t *buffer) {
     aes256_ecb(buffer, ctr, 1, &ctx);
 }
 
-void nist_kat_init(uint8_t *entropy_input, uint8_t *personalization_string, int security_strength);
-void nist_kat_init(uint8_t *entropy_input, uint8_t *personalization_string, int security_strength) {
+void nist_kat_init(uint8_t *entropy_input, const uint8_t *personalization_string, int security_strength);
+void nist_kat_init(uint8_t *entropy_input, const uint8_t *personalization_string, int security_strength) {
     uint8_t seed_material[48];
 
     assert(security_strength == 256);
     memcpy(seed_material, entropy_input, 48);
-    if (personalization_string)
+    if (personalization_string) {
         for (int i = 0; i < 48; i++) {
             seed_material[i] ^= personalization_string[i];
         }
+    }
     memset(DRBG_ctx.Key, 0x00, 32);
     memset(DRBG_ctx.V, 0x00, 16);
     AES256_CTR_DRBG_Update(seed_material, DRBG_ctx.Key, DRBG_ctx.V);
     DRBG_ctx.reseed_counter = 1;
 }
 
-int randombytes(uint8_t *x, size_t xlen) {
+int randombytes(uint8_t *buf, size_t xlen) {
     uint8_t block[16];
     int i = 0;
 
@@ -63,11 +64,11 @@ int randombytes(uint8_t *x, size_t xlen) {
         }
         AES256_ECB(DRBG_ctx.Key, DRBG_ctx.V, block);
         if (xlen > 15) {
-            memcpy(x + i, block, 16);
+            memcpy(buf + i, block, 16);
             i += 16;
             xlen -= 16;
         } else {
-            memcpy(x + i, block, xlen);
+            memcpy(buf + i, block, xlen);
             xlen = 0;
         }
     }
@@ -76,7 +77,7 @@ int randombytes(uint8_t *x, size_t xlen) {
     return 0;
 }
 
-static void AES256_CTR_DRBG_Update(uint8_t *provided_data, uint8_t *Key, uint8_t *V) {
+static void AES256_CTR_DRBG_Update(const uint8_t *provided_data, uint8_t *Key, uint8_t *V) {
     uint8_t temp[48];
 
     for (int i = 0; i < 3; i++) {
@@ -92,10 +93,11 @@ static void AES256_CTR_DRBG_Update(uint8_t *provided_data, uint8_t *Key, uint8_t
 
         AES256_ECB(Key, V, temp + 16 * i);
     }
-    if (provided_data != NULL)
+    if (provided_data != NULL) {
         for (int i = 0; i < 48; i++) {
             temp[i] ^= provided_data[i];
         }
+    }
     memcpy(Key, temp, 32);
     memcpy(V, temp + 32, 16);
 }
diff --git a/crypto_kem/frodokem1344aes/clean/noise.c b/crypto_kem/frodokem1344aes/clean/noise.c
index d83162bc..04f5c48e 100644
--- a/crypto_kem/frodokem1344aes/clean/noise.c
+++ b/crypto_kem/frodokem1344aes/clean/noise.c
@@ -16,7 +16,7 @@ void PQCLEAN_FRODOKEM1344AES_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i, j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem1344shake/clean/noise.c b/crypto_kem/frodokem1344shake/clean/noise.c
index decce08a..611a6527 100644
--- a/crypto_kem/frodokem1344shake/clean/noise.c
+++ b/crypto_kem/frodokem1344shake/clean/noise.c
@@ -16,7 +16,7 @@ void PQCLEAN_FRODOKEM1344SHAKE_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i, j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem640aes/clean/noise.c b/crypto_kem/frodokem640aes/clean/noise.c
index 2221219e..437ea69d 100644
--- a/crypto_kem/frodokem640aes/clean/noise.c
+++ b/crypto_kem/frodokem640aes/clean/noise.c
@@ -16,7 +16,7 @@ void PQCLEAN_FRODOKEM640AES_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i, j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem640shake/clean/noise.c b/crypto_kem/frodokem640shake/clean/noise.c
index 08c975d5..d64e6f1c 100644
--- a/crypto_kem/frodokem640shake/clean/noise.c
+++ b/crypto_kem/frodokem640shake/clean/noise.c
@@ -16,7 +16,7 @@ void PQCLEAN_FRODOKEM640SHAKE_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i, j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem976aes/clean/noise.c b/crypto_kem/frodokem976aes/clean/noise.c
index 45d868ed..f830f71e 100644
--- a/crypto_kem/frodokem976aes/clean/noise.c
+++ b/crypto_kem/frodokem976aes/clean/noise.c
@@ -16,7 +16,7 @@ void PQCLEAN_FRODOKEM976AES_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i, j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;
diff --git a/crypto_kem/frodokem976shake/clean/noise.c b/crypto_kem/frodokem976shake/clean/noise.c
index b2b4f2dc..3ef673f5 100644
--- a/crypto_kem/frodokem976shake/clean/noise.c
+++ b/crypto_kem/frodokem976shake/clean/noise.c
@@ -16,7 +16,7 @@ void PQCLEAN_FRODOKEM976SHAKE_CLEAN_sample_n(uint16_t *s, size_t n) {
     // Fills vector s with n samples from the noise distribution which requires 16 bits to sample.
     // The distribution is specified by its CDF.
     // Input: pseudo-random values (2*n bytes) passed in s. The input is overwritten by the output.
-    unsigned int i, j;
+    size_t i, j;
 
     for (i = 0; i < n; ++i) {
         uint8_t sample = 0;