List of free rfc3161 servers.

rfc3161.txt

https://rfc3161.ai.moda
https://rfc3161.ai.moda/adobe
https://rfc3161.ai.moda/microsoft
https://rfc3161.ai.moda/apple
https://rfc3161.ai.moda/any
http://rfc3161.ai.moda
http://timestamp.digicert.com
http://timestamp.globalsign.com/tsa/r6advanced1
http://rfc3161timestamp.globalsign.com/advanced
http://timestamp.sectigo.com
http://timestamp.apple.com/ts01
http://tsa.mesign.com
http://time.certum.pl
https://freetsa.org
http://tsa.startssl.com/rfc3161
http://dse200.ncipher.com/TSS/HttpTspServer
http://zeitstempel.dfn.de
https://ca.signfiles.com/tsa/get.aspx
http://services.globaltrustfinder.com/adss/tsa
https://tsp.iaik.tugraz.at/tsp/TspRequest
http://timestamp.entrust.net/TSS/RFC3161sha2TS
http://timestamp.acs.microsoft.com

@chimmmpie I have made a script that extracts the .cer / .crt from a timestamping service

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

# Check that we have the name of the TSA service as a first arg and the URL as a second arg
if [ "$#" -ne 2 ]; then
    echo "Illegal number of parameters"
    echo "Usage: $0 <TSA_URL> <TSA_NAME>"
    exit 1
fi

TSA_URL=$1
TSA_NAME=$2

echo "==> We are trying to get the TSA certificate from the following service : $TSA_NAME ($TSA_URL)"

echo "==> Sending a signature request..."
openssl rand 256 | openssl ts -query -data - -cert -sha256 | curl -s -S --data-binary @- "$TSA_URL" --header "Content-Type: application/timestamp-query" -o - -v > "$TSA_NAME.reply.tsr"

echo "==> Verifying the response..."
openssl ts -reply -text -in "$TSA_NAME.reply.tsr" || (echo "==> Verification failed :" && cat "$TSA_NAME.reply.tsr" && rm "$TSA_NAME.reply.tsr" && exit 1)

echo "==> Extracting the token..."
openssl ts -reply -in "$TSA_NAME.reply.tsr" -token_out -out "$TSA_NAME.token.tk"

echo "==> Extracting the TSA certificate..."
openssl pkcs7 -inform DER -in "$TSA_NAME.token.tk" -print_certs -outform PEM -out "$TSA_NAME.cer"

echo "==> Extracting the TSA certificate as a .crt..."
openssl x509 -inform PEM -in "$TSA_NAME.cer" -out "$TSA_NAME.crt"

rm "$TSA_NAME.reply.tsr" "$TSA_NAME.token.tk"

Call it like ./request_crt.sh http://timestamp.acs.microsoft.com/ microsoft to get everything in microsoft.crt

I have made a script that extracts the .cer / .crt from a timestamping service

Thanks, that is great!

Would it be possible to make version of the script that downloads all certs for servers provided by https://rfc3161.ai.moda/servers.json?

@chimmmpie I have made a script that extracts the .cer / .crt from a timestamping service

That looks interesting. But it would suggest to me that the cert is already in the response? Or does anyone think that some of the openssl commands will fetch it in the background?

The -certpart in openssl ts -query -data - -cert -sha256 asks the TSA to return its cert as well

@Pique7 You can use them for anything, many folks are using https://rfc3161.ai.moda in production. We serve a few million requests per month now I think, with higher uptime than the majority of any single RFC3161 server (since we have automatic failovers).

Thanks for your reply. Now I have another question:
The TSA certificate of my current test response has a validity of 10 years. I thinks that's a lot. But what can I do when the TSA certificate expires? Sorry if this question is too stupid or off-topic/misplaced.

The signature should still be considered valid (in my opinion), since it was signed within the original lifetime of the CA. It just can’t (or rather shouldn’t) be used for new signatures.

You shouldn’t have to do anything. All of the upstream servers for rfc3161.ai.moda should rollover to using a new certificates long before the current ones expire.

I you want to see the CA that was used in the response for your request, you can use asn1parse. Example:

openssl rand 512 | openssl ts -query -data - -cert -sha512 | curl -s -S --data-binary @- https://rfc3161.ai.moda -o - -v | openssl asn1parse -in /dev/stdin -inform DER -dump

Thanks for tip.

But once again: we are not able to generate a time stamp unless we have CA root certificate in the local "trusted" list.
Would it be possible to provide a list (URLs) of all available timestamping CA root certificates?

@vasekkral Sure. Note, these certificates do change over time.

#!/usr/bin/env bash

# Available cryptographic hash algorithms for timestamp requests
# These algorithms are tried sequentially until a successful response is received
hash_algorithms=(
    "sha512" "blake2b512" "blake2s256" "md4" "md5" "md5-sha1" "mdc2" "ripemd"
    "ripemd160" "rmd160" "sha1" "sha224" "sha256" "sha3-224" "sha3-256"
    "sha3-384" "sha3-512" "sha384" "sha512-224" "sha512-256" "shake128"
    "shake256" "sm3" "ssl3-md5" "ssl3-sha1" "whirlpool"
)

# Attempts to obtain a timestamp token from a TSA server using specified parameters
# Returns 0 on success, 1 on failure
try_timestamp_request() {
    local url="$1"          # TSA server endpoint
    local hash_algo="$2"    # Cryptographic hash algorithm
    local tmp_query="$3"    # Path to store the timestamp request
    local tmp_reply="$4"    # Path to store the server's response
    local tmp_token="$5"    # Path to store the extracted timestamp token

    # Process flow:
    # 1. Generate random data as input
    # 2. Create a timestamp query using the specified hash algorithm
    # 3. Send the query to the TSA server
    # 4. Extract the timestamp token from the response
    if openssl rand 512 | \
       openssl ts -query -data - -cert -"$hash_algo" > "$tmp_query" 2>/dev/null && \
       curl -H "Content-Type: application/timestamp-query" \
            -H "Accept: application/timestamp-reply" \
            -s -S --data-binary @"$tmp_query" "$url" -o "$tmp_reply" && \
       openssl ts -reply -in "$tmp_reply" -token_out -out "$tmp_token" 2>/dev/null; then
        return 0    # All operations completed successfully
    else
        return 1    # One or more operations failed
    fi
}

# Main processing loop: Retrieve and process TSA server information
curl -s https://rfc3161.ai.moda/servers.json | \
jq -r '.[] | {name: .name, url: .url} | @json' | \
while read -r line; do
    # Extract server details from JSON response
    name=$(echo "$line" | jq -r '.name')   # Server's friendly name
    url=$(echo "$line" | jq -r '.url')     # Server's API endpoint

    # Create filesystem-safe server name by removing special characters
    safe_name=$(echo "$name" | tr -c '[:alnum:]' '_' | tr -s '_' | sed 's/^_//;s/_$//')

    # Create temporary storage for request/response data
    tmp_query=$(mktemp)
    tmp_reply=$(mktemp)
    tmp_token=$(mktemp)

    success=false           # Tracks if any attempt succeeded
    successful_hash=""      # Records which hash algorithm worked

    # Try each hash algorithm until successful
    for hash_algo in "${hash_algorithms[@]}"; do
        echo "Trying $hash_algo for $name..."
        if try_timestamp_request "$url" "$hash_algo" "$tmp_query" "$tmp_reply" "$tmp_token"; then
            success=true
            successful_hash="$hash_algo"
            break
        fi
    done

    if [ "$success" = true ]; then
        # Extract and save the CA certificate from the successful response
        if openssl pkcs7 -inform DER -in "$tmp_token" -print_certs -outform PEM -out "${safe_name}.pem" 2>/dev/null; then
            echo "Successfully extracted CA certificate for: $name (using $successful_hash)"
            echo "$name,$url,$successful_hash" >> successful_servers.log
        else
            echo "$url" >> failed_ca_certs.log
            echo "Failed to extract CA certificate for: $name"
        fi
    else
        echo "$url" >> failed_ca_certs.log
        echo "Failed to get timestamp response from: $name (tried all hash algorithms)"
    fi

    # Cleanup temporary files to prevent disk space issues
    rm -f "$tmp_query" "$tmp_reply" "$tmp_token"
done

This will dump the full certificate chain for all of the CAs. e.g. this is what my folder looks like after running the script:

APED.pem					Entrust.pem					QuoVadis_China.pem
Adacom.pem					FreeTSA.pem					QuoVadis_EU.pem
Aloaha.pem					GlobalSign.pem					SDA_GOV_GE.pem
Apple.pem					IdenTrust.pem					SEP_Bulgaria.pem
Azure.pem					Instituto_dos_Registos_e_do_Notariado_I_P.pem	SSL_com.pem
BalTstamp.pem					Izenpe.pem					Sectigo.pem
Belgium_Federal_Goverment.pem			Lex_Persona.pem					SwissSign.pem
CNBS.pem					Mahidol_University.pem				Swiss_Goverment.pem
CatCert.pem					MeSign.pem					TSA_SINPE.pem
Certum.pem					Netlock.pem					successful_servers.log
Digicert.pem					QuoVadis.pem

@Manouchehri great, thanks a lot, works perfectly. Now we can call our "time stamper" util with your load balancer.