diff --git a/isap/Implementations/crypto_aead/isapa128av20/opt_32/decrypt.c b/isap/Implementations/crypto_aead/isapa128av20/opt_32/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapa128av20/opt_32/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapa128av20/opt_32_armv67m/decrypt.c b/isap/Implementations/crypto_aead/isapa128av20/opt_32_armv67m/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapa128av20/opt_32_armv67m/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapa128av20/opt_64/decrypt.c b/isap/Implementations/crypto_aead/isapa128av20/opt_64/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapa128av20/opt_64/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapa128v20/opt_32/decrypt.c b/isap/Implementations/crypto_aead/isapa128v20/opt_32/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapa128v20/opt_32/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapa128v20/opt_32_armv67m/decrypt.c b/isap/Implementations/crypto_aead/isapa128v20/opt_32_armv67m/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapa128v20/opt_32_armv67m/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapa128v20/opt_64/decrypt.c b/isap/Implementations/crypto_aead/isapa128v20/opt_64/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapa128v20/opt_64/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapk128av20/opt_32_armv6m/decrypt.c b/isap/Implementations/crypto_aead/isapk128av20/opt_32_armv6m/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapk128av20/opt_32_armv6m/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapk128av20/opt_32_armv7m/decrypt.c b/isap/Implementations/crypto_aead/isapk128av20/opt_32_armv7m/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapk128av20/opt_32_armv7m/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapk128v20/opt_32_armv6m/decrypt.c b/isap/Implementations/crypto_aead/isapk128v20/opt_32_armv6m/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapk128v20/opt_32_armv6m/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+
diff --git a/isap/Implementations/crypto_aead/isapk128v20/opt_32_armv7m/decrypt.c b/isap/Implementations/crypto_aead/isapk128v20/opt_32_armv7m/decrypt.c
new file mode 100644
index 0000000..1fbbdeb
--- /dev/null
+++ b/isap/Implementations/crypto_aead/isapk128v20/opt_32_armv7m/decrypt.c
@@ -0,0 +1,39 @@
+#include <stdio.h>
+#include <string.h>
+#include "api.h"
+#include "isap.h"
+
+int crypto_aead_decrypt(
+	unsigned char *m, unsigned long long *mlen,
+	unsigned char *nsec,
+	const unsigned char *c, unsigned long long clen,
+	const unsigned char *ad, unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+){
+    (void)nsec;
+
+	// Plaintext length is clen - tag length
+	*mlen = clen-ISAP_TAG_SZ;
+
+	// Generate tag
+	unsigned char tag[ISAP_TAG_SZ];
+	isap_mac(k,npub,ad,adlen,c,*mlen,tag);
+
+	// Compare tag
+	unsigned long eq_cnt = 0;
+	for(unsigned int i = 0; i < ISAP_TAG_SZ; i++) {
+		eq_cnt += (tag[i] == c[(*mlen)+i]);
+	}
+
+	// Perform decryption if tag is correct
+	if(eq_cnt == (unsigned long)ISAP_TAG_SZ){
+		if (*mlen > 0) {
+			isap_enc(k,npub,c,*mlen,m);
+		}
+		return 0;
+	} else {
+		return -1;
+	}
+}
+