diff --git a/libavformat/crypto.c b/libavformat/crypto.c
index 346c7061b4..9a48f2e6f5 100644
--- a/libavformat/crypto.c
+++ b/libavformat/crypto.c
@@ -54,10 +54,10 @@ typedef struct CryptoContext {
     int encrypt_ivlen;
     struct AVAES *aes_decrypt;
     struct AVAES *aes_encrypt;
-
+    uint8_t *write_buf;
+    unsigned int write_buf_size;
     uint8_t pad[BLOCKSIZE];
     int pad_len;
-
 } CryptoContext;
 
 #define OFFSET(x) offsetof(CryptoContext, x)
@@ -80,16 +80,16 @@ static const AVClass crypto_class = {
     .version        = LIBAVUTIL_VERSION_INT,
 };
 
-static int set_aes_arg(CryptoContext *c, uint8_t **buf, int *buf_len,
+static int set_aes_arg(URLContext *h, uint8_t **buf, int *buf_len,
                        uint8_t *default_buf, int default_buf_len,
                        const char *desc)
 {
     if (!*buf_len) {
         if (!default_buf_len) {
-            av_log(c, AV_LOG_ERROR, "%s not set\n", desc);
+            av_log(h, AV_LOG_ERROR, "%s not set\n", desc);
             return AVERROR(EINVAL);
         } else if (default_buf_len != BLOCKSIZE) {
-            av_log(c, AV_LOG_ERROR,
+            av_log(h, AV_LOG_ERROR,
                    "invalid %s size (%d bytes, block size is %d)\n",
                    desc, default_buf_len, BLOCKSIZE);
             return AVERROR(EINVAL);
@@ -99,7 +99,7 @@ static int set_aes_arg(CryptoContext *c, uint8_t **buf, int *buf_len,
             return AVERROR(ENOMEM);
         *buf_len = default_buf_len;
     } else if (*buf_len != BLOCKSIZE) {
-        av_log(c, AV_LOG_ERROR,
+        av_log(h, AV_LOG_ERROR,
                "invalid %s size (%d bytes, block size is %d)\n",
                desc, *buf_len, BLOCKSIZE);
         return AVERROR(EINVAL);
@@ -121,23 +121,21 @@ static int crypto_open2(URLContext *h, const char *uri, int flags, AVDictionary
         goto err;
     }
 
-    c->position = 0;
-
     if (flags & AVIO_FLAG_READ) {
-        if ((ret = set_aes_arg(c, &c->decrypt_key, &c->decrypt_keylen,
+        if ((ret = set_aes_arg(h, &c->decrypt_key, &c->decrypt_keylen,
                                c->key, c->keylen, "decryption key")) < 0)
             goto err;
-        if ((ret = set_aes_arg(c, &c->decrypt_iv, &c->decrypt_ivlen,
+        if ((ret = set_aes_arg(h, &c->decrypt_iv, &c->decrypt_ivlen,
                                c->iv, c->ivlen, "decryption IV")) < 0)
             goto err;
     }
 
     if (flags & AVIO_FLAG_WRITE) {
-        if ((ret = set_aes_arg(c, &c->encrypt_key, &c->encrypt_keylen,
+        if ((ret = set_aes_arg(h, &c->encrypt_key, &c->encrypt_keylen,
                                c->key, c->keylen, "encryption key")) < 0)
         if (ret < 0)
             goto err;
-        if ((ret = set_aes_arg(c, &c->encrypt_iv, &c->encrypt_ivlen,
+        if ((ret = set_aes_arg(h, &c->encrypt_iv, &c->encrypt_ivlen,
                                c->iv, c->ivlen, "encryption IV")) < 0)
             goto err;
     }
@@ -155,7 +153,7 @@ static int crypto_open2(URLContext *h, const char *uri, int flags, AVDictionary
             ret = AVERROR(ENOMEM);
             goto err;
         }
-        ret = av_aes_init(c->aes_decrypt, c->decrypt_key, BLOCKSIZE*8, 1);
+        ret = av_aes_init(c->aes_decrypt, c->decrypt_key, BLOCKSIZE * 8, 1);
         if (ret < 0)
             goto err;
 
@@ -170,7 +168,7 @@ static int crypto_open2(URLContext *h, const char *uri, int flags, AVDictionary
             ret = AVERROR(ENOMEM);
             goto err;
         }
-        ret = av_aes_init(c->aes_encrypt, c->encrypt_key, BLOCKSIZE*8, 0);
+        ret = av_aes_init(c->aes_encrypt, c->encrypt_key, BLOCKSIZE * 8, 0);
         if (ret < 0)
             goto err;
         // for write, we must be streamed
@@ -178,8 +176,6 @@ static int crypto_open2(URLContext *h, const char *uri, int flags, AVDictionary
         h->is_streamed = 1;
     }
 
-    c->pad_len = 0;
-
 err:
     return ret;
 }
@@ -338,7 +334,6 @@ static int crypto_write(URLContext *h, const unsigned char *buf, int size)
 {
     CryptoContext *c = h->priv_data;
     int total_size, blocks, pad_len, out_size;
-    uint8_t *out_buf;
     int ret = 0;
 
     total_size = size + c->pad_len;
@@ -347,22 +342,23 @@ static int crypto_write(URLContext *h, const unsigned char *buf, int size)
     blocks = out_size / BLOCKSIZE;
 
     if (out_size) {
-        out_buf = av_malloc(out_size);
-        if (!out_buf)
+        av_fast_malloc(&c->write_buf, &c->write_buf_size, out_size);
+
+        if (!c->write_buf)
             return AVERROR(ENOMEM);
 
         if (c->pad_len) {
             memcpy(&c->pad[c->pad_len], buf, BLOCKSIZE - c->pad_len);
-            av_aes_crypt(c->aes_encrypt, out_buf, c->pad, 1, c->encrypt_iv, 0);
+            av_aes_crypt(c->aes_encrypt, c->write_buf, c->pad, 1, c->encrypt_iv, 0);
             blocks--;
         }
 
-        av_aes_crypt(c->aes_encrypt, &out_buf[c->pad_len ? BLOCKSIZE : 0],
-                             &buf[c->pad_len ? BLOCKSIZE - c->pad_len: 0],
-                             blocks, c->encrypt_iv, 0);
+        av_aes_crypt(c->aes_encrypt,
+                     &c->write_buf[c->pad_len ? BLOCKSIZE : 0],
+                     &buf[c->pad_len ? BLOCKSIZE - c->pad_len : 0],
+                     blocks, c->encrypt_iv, 0);
 
-        ret = ffurl_write(c->hd, out_buf, out_size);
-        av_free(out_buf);
+        ret = ffurl_write(c->hd, c->write_buf, out_size);
         if (ret < 0)
             return ret;
 
@@ -378,22 +374,23 @@ static int crypto_write(URLContext *h, const unsigned char *buf, int size)
 static int crypto_close(URLContext *h)
 {
     CryptoContext *c = h->priv_data;
-    uint8_t out_buf[BLOCKSIZE];
-    int ret, pad;
+    int ret = 0;
 
     if (c->aes_encrypt) {
-        pad = BLOCKSIZE - c->pad_len;
+        uint8_t out_buf[BLOCKSIZE];
+        int pad = BLOCKSIZE - c->pad_len;
+
         memset(&c->pad[c->pad_len], pad, pad);
         av_aes_crypt(c->aes_encrypt, out_buf, c->pad, 1, c->encrypt_iv, 0);
-        if ((ret =  ffurl_write(c->hd, out_buf, BLOCKSIZE)) < 0)
-            return ret;
+        ret = ffurl_write(c->hd, out_buf, BLOCKSIZE);
     }
 
     if (c->hd)
         ffurl_close(c->hd);
     av_freep(&c->aes_decrypt);
     av_freep(&c->aes_encrypt);
-    return 0;
+    av_freep(&c->write_buf);
+    return ret;
 }
 
 const URLProtocol ff_crypto_protocol = {