vszakats · Sep 11, 2026 · Sep 11, 2026 · Sep 11, 2026 · Sep 11, 2026 · Sep 11, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -514,9 +514,6 @@ jobs:
             cflags+=' -DLIBSSH2_KEX_SHA1_ENABLE -DLIBSSH2_MD5_ENABLE -DLIBSSH2_MD5_PEM_ENABLE -DLIBSSH2_HMAC_SHA1_ENABLE -DLIBSSH2_HMAC_RIPEMD_ENABLE'
             cflags+=' -DLIBSSH2_RSA_SHA1_ENABLE -DLIBSSH2_BLOWFISH_ENABLE -DLIBSSH2_RC4_ENABLE -DLIBSSH2_CAST_ENABLE -DLIBSSH2_3DES_ENABLE'
           fi
-          if [ "${MATRIX_TARGET}" = 'distcheck' ]; then
-            cflags+=' -DLIBSSH2_DSA_ENABLE'  # build test only, it cannot pass test in CI
-          fi
           if [ "${MATRIX_BUILD}" = 'CM' ]; then
             if [ "${MATRIX_CRYPTO}" = 'AWS-LC' ] || \
                [ "${MATRIX_CRYPTO}" = 'BoringSSL' ] || \
@@ -890,7 +887,6 @@ jobs:
           if [ "${MATRIX_TEST}" = 'legacy-options' ]; then
             cflags+=' -DLIBSSH2_KEX_SHA1_ENABLE -DLIBSSH2_MD5_ENABLE -DLIBSSH2_MD5_PEM_ENABLE -DLIBSSH2_HMAC_SHA1_ENABLE -DLIBSSH2_HMAC_RIPEMD_ENABLE'
             cflags+=' -DLIBSSH2_RSA_SHA1_ENABLE -DLIBSSH2_BLOWFISH_ENABLE -DLIBSSH2_RC4_ENABLE -DLIBSSH2_CAST_ENABLE -DLIBSSH2_3DES_ENABLE'
-            cflags+=' -DLIBSSH2_DSA_ENABLE'
           fi
           if [ "${MATRIX_BUILD}" = 'CM' ]; then
             if [[ "${MATRIX_ENV}" = 'clang'* ]]; then
@@ -1028,7 +1024,6 @@ jobs:
             options+=" -DENABLE_ECDSA_WINCNG=${MATRIX_WINCND_ECDSA}"
             cflags+=' -DLIBSSH2_KEX_SHA1_ENABLE -DLIBSSH2_MD5_ENABLE -DLIBSSH2_MD5_PEM_ENABLE -DLIBSSH2_HMAC_SHA1_ENABLE'
             cflags+=' -DLIBSSH2_RSA_SHA1_ENABLE -DLIBSSH2_BLOWFISH_ENABLE -DLIBSSH2_RC4_ENABLE -DLIBSSH2_3DES_ENABLE'
-            cflags+=' -DLIBSSH2_DSA_ENABLE'
           fi
           cmake -B bld ${options} \
             -DCMAKE_C_FLAGS="${cflags}" \
@@ -1377,7 +1372,6 @@ jobs:
             options+=" -DENABLE_ECDSA_WINCNG=${MATRIX_WINCND_ECDSA}"
             cflags+=' -DLIBSSH2_KEX_SHA1_ENABLE -DLIBSSH2_MD5_ENABLE -DLIBSSH2_MD5_PEM_ENABLE -DLIBSSH2_HMAC_SHA1_ENABLE'
             cflags+=' -DLIBSSH2_RSA_SHA1_ENABLE -DLIBSSH2_BLOWFISH_ENABLE -DLIBSSH2_RC4_ENABLE -DLIBSSH2_3DES_ENABLE'
-            cflags+=' -DLIBSSH2_DSA_ENABLE'
           fi
           cmake -B bld ${options} \
             -DCMAKE_INSTALL_PREFIX="$HOME"/libssh2-install \

diff --git a/RELEASE-NOTES b/RELEASE-NOTES
@@ -2,6 +2,10 @@ libssh2 1.11.2_DEV
 
 Deprecation notices:
 
+- This release drops this feature:
+
+  - DSA: `ssh-dss` host keys and public-key authentication.
+
 - This release disables these options by default:
 
   - SHA1-based host key methods and signatures: `ssh-rsa`,
@@ -14,9 +18,6 @@ Deprecation notices:
     - `diffie-hellman-group-exchange-sha1`
     You can enable them with `-DLIBSSH2_KEX_SHA1_ENABLE`.
 
-  - DSA: `ssh-dss` host keys.
-    You can enable it with `-DLIBSSH2_DSA_ENABLE`.
-
   - SHA1-based MACs: `hmac-sha1`, `hmac-sha1-etm@openssh.com`, `hmac-sha1-96`
     You can enable them with `-DLIBSSH2_HMAC_SHA1_ENABLE`.
 

diff --git a/docs/libssh2_knownhost_add.md b/docs/libssh2_knownhost_add.md
@@ -63,9 +63,8 @@ LIBSSH2_KNOWNHOST_KEYENC_RAW or LIBSSH2_KNOWNHOST_KEYENC_BASE64.
 
 The key is using one of these algorithms:
 LIBSSH2_KNOWNHOST_KEY_RSA1, LIBSSH2_KNOWNHOST_KEY_SSHRSA,
-LIBSSH2_KNOWNHOST_KEY_SSHDSS (deprecated), LIBSSH2_KNOWNHOST_KEY_ECDSA_256,
-LIBSSH2_KNOWNHOST_KEY_ECDSA_384, LIBSSH2_KNOWNHOST_KEY_ECDSA_521 or
-LIBSSH2_KNOWNHOST_KEY_ED25519.
+LIBSSH2_KNOWNHOST_KEY_ECDSA_256, LIBSSH2_KNOWNHOST_KEY_ECDSA_384,
+LIBSSH2_KNOWNHOST_KEY_ECDSA_521 or LIBSSH2_KNOWNHOST_KEY_ED25519.
 
 *store* should point to a pointer that gets filled in to point to the
 known host data after the addition. NULL can be passed if you do not care about

diff --git a/docs/libssh2_knownhost_addc.md b/docs/libssh2_knownhost_addc.md
@@ -67,9 +67,8 @@ LIBSSH2_KNOWNHOST_KEYENC_RAW or LIBSSH2_KNOWNHOST_KEYENC_BASE64.
 
 The key is using one of these algorithms:
 LIBSSH2_KNOWNHOST_KEY_RSA1, LIBSSH2_KNOWNHOST_KEY_SSHRSA,
-LIBSSH2_KNOWNHOST_KEY_SSHDSS (deprecated), LIBSSH2_KNOWNHOST_KEY_ECDSA_256,
-LIBSSH2_KNOWNHOST_KEY_ECDSA_384, LIBSSH2_KNOWNHOST_KEY_ECDSA_521 or
-LIBSSH2_KNOWNHOST_KEY_ED25519.
+LIBSSH2_KNOWNHOST_KEY_ECDSA_256, LIBSSH2_KNOWNHOST_KEY_ECDSA_384,
+LIBSSH2_KNOWNHOST_KEY_ECDSA_521 or LIBSSH2_KNOWNHOST_KEY_ED25519.
 
 *store* should point to a pointer that gets filled in to point to the
 known host data after the addition. NULL can be passed if you do not care about

diff --git a/docs/libssh2_session_hostkey.md b/docs/libssh2_session_hostkey.md
@@ -28,10 +28,9 @@ Returns a pointer to the current host key, the value *len* points to
 gets the length of the key.
 
 The value *type* points to the type of host key which is one of:
-LIBSSH2_HOSTKEY_TYPE_RSA, LIBSSH2_HOSTKEY_TYPE_DSS (deprecated),
-LIBSSH2_HOSTKEY_TYPE_ECDSA_256, LIBSSH2_HOSTKEY_TYPE_ECDSA_384,
-LIBSSH2_HOSTKEY_TYPE_ECDSA_521, LIBSSH2_HOSTKEY_TYPE_ED25519 or
-LIBSSH2_HOSTKEY_TYPE_UNKNOWN.
+LIBSSH2_HOSTKEY_TYPE_RSA, LIBSSH2_HOSTKEY_TYPE_ECDSA_256,
+LIBSSH2_HOSTKEY_TYPE_ECDSA_384, LIBSSH2_HOSTKEY_TYPE_ECDSA_521,
+LIBSSH2_HOSTKEY_TYPE_ED25519 or LIBSSH2_HOSTKEY_TYPE_UNKNOWN.
 
 # RETURN VALUE
 

diff --git a/include/libssh2.h b/include/libssh2.h
@@ -438,7 +438,7 @@ typedef struct _LIBSSH2_POLLFD {
 #define LIBSSH2_HOSTKEY_TYPE_UNKNOWN            0
 #define LIBSSH2_HOSTKEY_TYPE_RSA                1
 #ifndef LIBSSH2_NO_DEPRECATED
-#define LIBSSH2_HOSTKEY_TYPE_DSS                2  /* deprecated */
+#define LIBSSH2_HOSTKEY_TYPE_DSS                2  /* obsolete, unused */
 #endif
 #define LIBSSH2_HOSTKEY_TYPE_ECDSA_256          3
 #define LIBSSH2_HOSTKEY_TYPE_ECDSA_384          4

diff --git a/os400/README400 b/os400/README400
@@ -17,8 +17,7 @@ additional procedures are provided for string transcoding (see below). No
 wrappers to standard procedures are provided: however, nested calls to
 transcoding procedures may be used.
 
-Crypto API is provided by the IBM QC3 API library. It supports RSA and EC,
-but not DSA.
+Crypto API is provided by the IBM QC3 API library. It supports RSA and EC.
 
   Standard compilation environment does support neither autotools nor make;
 in fact, few common utilities are available. As a consequence, the

diff --git a/src/HACKING-CRYPTO.md b/src/HACKING-CRYPTO.md
@@ -378,16 +378,6 @@ Format of an RSA public key:
 
 Each item is preceded by its 32-bit byte length, MSB first.
 
-Format of a DSA public key:
-
-1. "ssh-dss".
-2. p, MSB first, with high order bit = 0.
-3. q, MSB first, with high order bit = 0.
-4. g, MSB first, with high order bit = 0.
-5. pub_key, MSB first, with high order bit = 0.
-
-Each item is preceded by its 32-bit byte length, MSB first.
-
 Format of an ECDSA public key:
 
 1. `ecdsa-sha2-nistp256` or `ecdsa-sha2-nistp384` or `ecdsa-sha2-nistp521`.
@@ -557,71 +547,7 @@ based on hash length and the RSA context.
 Return 0 if OK, else -1.
 This procedure is already prototyped in `crypto.h`.
 
-### 7.2) DSA
-
-`LIBSSH2_DSA`: define as 1 if the crypto library supports DSA, else 0. If
-defined as 0, the rest of this section can be omitted.
-
-`ssh2_dsa_ctx`: Type of a DSA computation context. Generally a struct.
-
-```c
-int ssh2_dsa_new(ssh2_dsa_ctx **dsa, LIBSSH2_SESSION *session,
-                 const unsigned char *pdata, size_t plen,
-                 const unsigned char *qdata, size_t qlen,
-                 const unsigned char *gdata, size_t glen,
-                 const unsigned char *ydata, size_t ylen,
-                 const unsigned char *x, size_t x_len);
-```
-
-Creates a new context for DSA computations from source key values:
-
-- `pdata`, `plen` Prime number p. Only used if private key known (`ddata`).
-- `qdata`, `qlen` Prime number q. Only used if private key known (`ddata`).
-- `gdata`, `glen` G number.
-- `ydata`, `ylen` Public key.
-- `xdata`, `xlen` Private key. Only taken if xlen non-zero.
-
-Returns 0 if OK.
-This procedure is already prototyped in `crypto.h`.
-
-```c
-int ssh2_dsa_new_priv(ssh2_dsa_ctx **dsa,
-                      LIBSSH2_SESSION *session,
-                      const char *filename,
-                      const char *blob, size_t blob_len,
-                      const char *passphrase);
-```
-Reads a DSA private key from file `filename`, or `blob` into a new DSA
-context.
-Must call `ssh2_init_if_needed()`.
-Returns 0 if OK, else -1.
-This procedure is already prototyped in `crypto.h`.
-
-```c
-int ssh2_dsa_sha1_verify(ssh2_dsa_ctx *dsa, LIBSSH2_SESSION *session,
-                         const unsigned char *sig,
-                         const unsigned char *m, size_t m_len);
-```
-Verify (`sig`, `siglen`) signature of (`m`, `m_len`) using an SHA-1 hash and
-the DSA context.
-Returns 0 if OK, else -1.
-This procedure is already prototyped in `crypto.h`.
-
-```c
-int ssh2_dsa_sha1_sign(ssh2_dsa_ctx *dsa, LIBSSH2_SESSION *session,
-                       const unsigned char *hash,
-                       size_t hash_len, unsigned char *sig);
-```
-DSA signs the (`hash`, `hash_len`) data using SHA-1 and store the signature at
-`sig`. Returns 0 if OK, else -1.
-This procedure is already prototyped in `crypto.h`.
-
-```c
-void ssh2_dsa_free(ssh2_dsa_ctx *dsa, LIBSSH2_SESSION *session);
-```
-Releases the DSA computation context at `dsa`.
-
-### 7.3) ECDSA
+### 7.2) ECDSA
 
 `LIBSSH2_ECDSA`: define as 1 if the crypto library supports ECDSA, else 0. If
 defined as 0, `ssh2_ec_key` should be defined as void and the rest of this
@@ -723,7 +649,7 @@ void ssh2_ecdsa_free(ssh2_ecdsa_ctx *ec_ctx, LIBSSH2_SESSION *session);
 ```
 Releases the ECDSA computation context at `ec_ctx`.
 
-### 7.4) ED25519
+### 7.3) ED25519
 
 `LIBSSH2_ED25519`: define as 1 if the crypto library supports ED25519, else 0.
 If defined as 0, the rest of this section can be omitted.

diff --git a/src/crypto.h b/src/crypto.h
@@ -160,29 +160,6 @@ void ssh2_rsa_free(ssh2_rsa_ctx *rsa, LIBSSH2_SESSION *session);
 #endif
 #endif /* LIBSSH2_RSA */
 
-#if LIBSSH2_DSA
-int ssh2_dsa_new(ssh2_dsa_ctx **dsa, LIBSSH2_SESSION *session,
-                 const unsigned char *pdata, size_t plen,
-                 const unsigned char *qdata, size_t qlen,
-                 const unsigned char *gdata, size_t glen,
-                 const unsigned char *ydata, size_t ylen,
-                 const unsigned char *xdata, size_t xlen);
-int ssh2_dsa_new_priv(ssh2_dsa_ctx **dsa,
-                      LIBSSH2_SESSION *session,
-                      const char *filename,
-                      const char *blob, size_t blob_len,
-                      const char *passphrase);
-int ssh2_dsa_sha1_sign(ssh2_dsa_ctx *dsa, LIBSSH2_SESSION *session,
-                       const unsigned char *hash, size_t hash_len,
-                       unsigned char *signature);
-int ssh2_dsa_sha1_verify(ssh2_dsa_ctx *dsa, LIBSSH2_SESSION *session,
-                         const unsigned char *sig,
-                         const unsigned char *m, size_t m_len);
-#ifndef ssh2_dsa_free
-void ssh2_dsa_free(ssh2_dsa_ctx *dsa, LIBSSH2_SESSION *session);
-#endif
-#endif /* LIBSSH2_DSA */
-
 #if LIBSSH2_ECDSA
 /* Maximum uncompressed EC point length for NIST P-521:
  * two 521-bit coordinates rounded up to bytes, plus 1-byte format prefix.
@@ -323,10 +300,6 @@ void ssh2_dh_dtor(ssh2_dh_ctx *dhctx);
 #define PEM_RSA_HEADER          "-----BEGIN RSA PRIVATE KEY-----"
 #define PEM_RSA_FOOTER          "-----END RSA PRIVATE KEY-----"
 #endif
-#if LIBSSH2_DSA
-#define PEM_DSA_HEADER          "-----BEGIN DSA PRIVATE KEY-----"
-#define PEM_DSA_FOOTER          "-----END DSA PRIVATE KEY-----"
-#endif
 #if LIBSSH2_ECDSA
 #define PEM_ECDSA_HEADER        "-----BEGIN EC PRIVATE KEY-----"
 #define PEM_ECDSA_FOOTER        "-----END EC PRIVATE KEY-----"

diff --git a/src/crypto_config.h b/src/crypto_config.h
@@ -20,11 +20,6 @@
 #define LIBSSH2_HMAC_RIPEMD 0
 #endif
 
-#ifndef LIBSSH2_DSA_ENABLE
-#undef LIBSSH2_DSA
-#define LIBSSH2_DSA 0
-#endif
-
 #ifdef LIBSSH2_NO_RSA
 #undef LIBSSH2_RSA
 #define LIBSSH2_RSA 0